/* RRviewer custom styles: palette, motion, interactions */
/* Brand logo size */
.brand-logo{ height:85px; width:auto; display:block; }
@media (max-width: 640px){ .brand-logo{ height:60px; } }

:root {
  --bg: #f8fafc; /* slate-50 */
  --text: #0f172a; /* slate-900 */
  --card-bg: #ffffff;
  --primary: #059669; /* emerald-600 */
  --primary-600: #047857; /* emerald-700 */
  --secondary: #2563eb; /* blue-600 */
  --danger: #ef4444; /* red-500 */
  --muted: #475569; /* slate-600 — better contrast */
  --ring: #34d399; /* emerald-400 */
  --border: rgba(2, 6, 23, 0.1);
  --shadow-color: rgba(2, 6, 23, 0.06);
  --ease-smooth: cubic-bezier(.2,.8,.2,1);
  --transition-fast: 160ms;
  --transition-normal: 260ms;
  --transition-slow: 360ms;
}

/* Dark theme vars */
:root[data-theme="dark"] {
  --bg: #0b1220;
  --text: #e5e7eb;
  --card-bg: #111827;
  --muted: #94a3b8;
  --border: rgba(148,163,184,0.15);
  --shadow-color: rgba(0,0,0,0.35);
}

html, body {
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Dark mode text color overrides for Tailwind utility classes */
:root[data-theme="dark"] .text-slate-900,
:root[data-theme="dark"] .text-slate-800,
:root[data-theme="dark"] .text-slate-700,
:root[data-theme="dark"] .text-slate-600 {
  color: var(--text) !important;
}
:root[data-theme="dark"] .text-slate-500,
:root[data-theme="dark"] .text-slate-400,
:root[data-theme="dark"] .text-slate-300,
:root[data-theme="dark"] .text-slate-200,
:root[data-theme="dark"] .text-slate-100 {
  color: var(--muted) !important;
}
:root[data-theme="dark"] .text-emerald-600 {
  color: #34d399 !important;
}
:root[data-theme="dark"] .text-emerald-700 {
  color: #10b981 !important;
}
:root[data-theme="dark"] .text-sky-700 {
  color: #38bdf8 !important;
}
:root[data-theme="dark"] .text-sky-600 {
  color: #0ea5e9 !important;
}
:root[data-theme="dark"] .text-slate-50 {
  color: #e5e7eb !important;
}

/* Dark mode background overrides for common Tailwind bg helpers */
:root[data-theme="dark"] .bg-slate-50 { background-color: var(--bg) !important; }
:root[data-theme="dark"] .bg-white { background-color: var(--card-bg) !important; }
:root[data-theme="dark"] .bg-slate-100 { background-color: color-mix(in srgb, var(--bg) 85%, #000) !important; }
:root[data-theme="dark"] .bg-emerald-50 { background-color: rgba(16,185,129,0.12) !important; }

/* Form controls base styling (inside cards) */
.rr-card textarea,
.rr-card input[type="text"],
.rr-card input[type="url"],
.rr-card input[type="email"],
.rr-card input[type="password"],
.rr-card select {
  background: var(--card-bg);
  color: var(--text);
  border: 1px solid var(--border);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}
:root[data-theme="dark"] .rr-card textarea,
:root[data-theme="dark"] .rr-card input[type="text"],
:root[data-theme="dark"] .rr-card input[type="url"],
:root[data-theme="dark"] .rr-card input[type="email"],
:root[data-theme="dark"] .rr-card input[type="password"],
:root[data-theme="dark"] .rr-card select {
  border-color: rgba(148,163,184,0.18);
}
.rr-card textarea::placeholder,
.rr-card input[type="text"]::placeholder,
.rr-card input[type="email"]::placeholder,
.rr-card input[type="password"]::placeholder { color: var(--muted); opacity: 1; }
/* Topbar and chip */
.topbar {
  /* distinct tinted background */
  background: linear-gradient(
    180deg,
    color-mix(in srgb, var(--card-bg) 85%, var(--primary) 15%) 0%,
    color-mix(in srgb, var(--card-bg) 94%, var(--primary) 6%) 100%
  );
  backdrop-filter: blur(6px);
  border-bottom: 1px solid rgba(2,6,23,0.08);
  box-shadow: 0 8px 20px rgba(2, 6, 23, 0.06);
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 40;
  transform: translateY(0);
  will-change: transform;
  transition: transform 180ms var(--ease-smooth), box-shadow 160ms var(--ease-smooth), background 160ms var(--ease-smooth);
}
.topbar--hidden { transform: translateY(-100%); }
.topbar-spacer { height: 68px; }
:root[data-theme="dark"] .topbar {
  background: linear-gradient(
    180deg,
    color-mix(in srgb, var(--card-bg) 88%, var(--primary-600) 12%) 0%,
    color-mix(in srgb, var(--card-bg) 95%, var(--primary-600) 5%) 100%
  );
  border-bottom-color: rgba(148,163,184,0.18);
}
.topbar::after {
  content: "";
  position: absolute; left: 0; right: 0; bottom: -1px; height: 2px;
  background: linear-gradient(90deg, #34d399 0%, #60a5fa 50%, #f59e0b 100%);
  opacity: 0.35;
  pointer-events: none;
}
.topbar--elevated {
  box-shadow: 0 12px 28px rgba(2, 6, 23, 0.08);
  border-bottom-color: rgba(2,6,23,0.14);
}
.chip { background: color-mix(in srgb, var(--bg) 40%, var(--card-bg)); border: 1px solid rgba(2,6,23,0.08); }
.topbar button, .topbar a { transition: background 160ms ease, color 160ms ease; }


body { animation: fadeIn 260ms var(--ease-smooth) both; }

.rr-card {
  background: var(--card-bg);
  box-shadow: 0 10px 25px var(--shadow-color);
  border: 1px solid var(--border);
  animation: floatIn var(--transition-slow) cubic-bezier(.2,.8,.2,1) both;
}

.rr-card:hover { 
  transition: transform var(--transition-normal) var(--ease-smooth), box-shadow var(--transition-normal) var(--ease-smooth);
  transform: translateY(-2px);
  box-shadow: 0 16px 32px var(--shadow-color);
}

@media (max-width: 768px) {
  .rr-card:hover { transform: none; box-shadow: 0 10px 25px var(--shadow-color); }
}

/* Output area should not be height-capped; allow page to scroll */
#gen-out-plain, #gen-out-pretty {
  max-height: none !important;
}

.rr-card button,
.rr-card a,
.rr-card select,
.rr-card textarea,
.rr-card input[type="file"] {
  transition: all 180ms var(--ease-smooth);
}

.rr-card button:hover,
.rr-card a:hover {
  transform: translateY(-1px);
}

/* Button primary/secondary states */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 0.375rem; font-weight: 600; border-radius: 0.5rem; }
.btn-primary { background: var(--primary); color: #fff; box-shadow: 0 6px 14px rgba(5,150,105,0.25); }
.btn-primary:hover { background: color-mix(in srgb, var(--primary) 92%, black); box-shadow: 0 10px 24px rgba(5,150,105,0.28); transform: translateY(-1px); }
.btn-primary:active { background: color-mix(in srgb, var(--primary) 88%, black); transform: translateY(0); box-shadow: 0 4px 10px rgba(5,150,105,0.22); }
.btn-secondary { background: color-mix(in srgb, var(--secondary) 92%, white); color: #fff; }
.btn-secondary:hover { background: color-mix(in srgb, var(--secondary) 96%, white); color: #fff; transform: translateY(-1px); }
.btn-secondary:active { color: #fff; transform: translateY(0); }

/* Back-to-top floating button */
.back-to-top {
  position: fixed; right: 20px; bottom: 24px; z-index: 50;
  width: 44px; height: 44px; border-radius: 9999px;
  background: color-mix(in srgb, var(--card-bg) 85%, var(--primary) 15%);
  border: 1px solid var(--border);
  box-shadow: 0 10px 24px var(--shadow-color);
  color: var(--text);
  font-size: 1.1rem;
  display: none; align-items: center; justify-content: center;
  transition: transform var(--transition-normal) var(--ease-smooth), opacity var(--transition-fast) var(--ease-smooth);
  cursor: pointer;
}
.back-to-top:hover { transform: translateY(-3px); box-shadow: 0 14px 32px var(--shadow-color); }
.back-to-top:active { transform: translateY(0); }
.back-to-top.show { display: flex; opacity: 1; }
@media (max-width: 640px) { .back-to-top { right: 12px; bottom: 16px; } }

.rr-card textarea,
.rr-card input[type="text"],
.rr-card select {
  outline: none !important;
  box-shadow: 0 0 0 0 rgba(0,0,0,0);
}

.rr-card textarea:focus,
.rr-card input[type="text"]:focus,
.rr-card input[type="email"]:focus,
.rr-card input[type="password"]:focus,
.rr-card select:focus {
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--ring) 35%, transparent);
  border-color: color-mix(in srgb, var(--ring) 60%, transparent);
}

/* Dark mode tweak for divider lines inside cards */
:root[data-theme="dark"] .rr-card .border-t { border-top-color: rgba(148,163,184,0.18) !important; }

a { text-underline-offset: 2px; }
a:hover { text-underline-offset: 3px; }

/* Brand-like link colors (respect themes) */
a { color: var(--secondary); }
a:hover { color: color-mix(in srgb, var(--secondary) 84%, black); }
:root[data-theme="dark"] a { color: #93c5fd; }
:root[data-theme="dark"] a:hover { color: #60a5fa; }

/* Better text selection */
::selection { background: color-mix(in srgb, var(--primary) 25%, transparent); color: var(--text); }

/* Accessible focus styles */
:where(button, a, input, textarea, select):focus-visible {
  outline: 3px solid color-mix(in srgb, var(--ring) 55%, transparent);
  outline-offset: 2px;
  border-radius: 6px;
}

/* Dark mode card refinements */
:root[data-theme="dark"] .rr-card {
  box-shadow: 0 10px 25px rgba(0,0,0,0.35);
  border-color: rgba(148,163,184,0.14);
}

/* Prose (Markdown view) dark theme tweaks */
:root[data-theme="dark"] .prose { color: #e5e7eb; }
:root[data-theme="dark"] .prose h1,
:root[data-theme="dark"] .prose h2,
:root[data-theme="dark"] .prose h3,
:root[data-theme="dark"] .prose h4 { color: #f3f4f6; }
:root[data-theme="dark"] .prose a { color: #93c5fd; }
:root[data-theme="dark"] .prose strong { color: #f3f4f6; }
:root[data-theme="dark"] .prose code {
  background: rgba(148,163,184,0.15);
  color: #f8fafc;
  border-radius: 4px;
  padding: 0.1em 0.3em;
}
:root[data-theme="dark"] .prose pre {
  background: #0b1220;
  color: #e5e7eb;
  border: 1px solid rgba(148,163,184,0.18);
  border-radius: 8px;
}

/* Markdown extras */
.prose pre { position: relative; overflow: auto; padding: 0.9em 1em; border: 1px solid rgba(2,6,23,0.08); border-radius: 8px; background:#f8fafc; }
:root[data-theme="dark"] .prose pre { background:#0b1220; }
.prose pre code { background: transparent !important; padding: 0 !important; }
.md-copy-btn { position:absolute; top:6px; right:8px; font-size:11px; background: rgba(0,0,0,0.55); color:#fff; padding:3px 8px; border-radius:6px; opacity:0; transition:opacity 140ms var(--ease-smooth); }
:root[data-theme="dark"] .md-copy-btn { background: rgba(255,255,255,0.18); }
.prose pre:hover .md-copy-btn, .prose pre:focus-within .md-copy-btn { opacity:1; }
.prose table { width:100%; border-collapse: collapse; font-size: 0.85rem; margin: 1em 0; }
.prose table th, .prose table td { border:1px solid rgba(2,6,23,0.15); padding:6px 10px; text-align:left; }
:root[data-theme="dark"] .prose table th, :root[data-theme="dark"] .prose table td { border-color: rgba(148,163,184,0.25); }
.prose blockquote { border-left:4px solid var(--primary); margin:1em 0; padding:0.5em 1em; background: rgba(5,150,105,0.05); border-radius:4px; }
:root[data-theme="dark"] .prose blockquote { background: rgba(5,150,105,0.12); }
.prose img { max-width:100%; height:auto; border-radius:6px; box-shadow:0 4px 14px rgba(0,0,0,0.08); }
.prose hr { border:0; height:1px; background: linear-gradient(90deg, rgba(2,6,23,0.08), rgba(2,6,23,0)); margin:2em 0; }
:root[data-theme="dark"] .prose hr { background: linear-gradient(90deg, rgba(148,163,184,0.25), rgba(148,163,184,0)); }

/* Markdown heading hierarchy */
.prose h1, .prose h2, .prose h3, .prose h4, .prose h5, .prose h6 { font-weight:600; line-height:1.25; scroll-margin-top:72px; position:relative; }
.prose h1 { font-size:1.9rem; margin:1.6em 0 .7em; padding-bottom:.25em; border-bottom:2px solid rgba(2,6,23,0.12); }
.prose h2 { font-size:1.55rem; margin:1.4em 0 .65em; padding-bottom:.2em; border-bottom:1px solid rgba(2,6,23,0.12); }
.prose h3 { font-size:1.25rem; margin:1.2em 0 .55em; }
.prose h1,.prose h2,.prose h3,.prose h4,.prose h5,.prose h6{position:relative}
.prose .heading-num{color:var(--c-text-dim);font-weight:600;margin-right:.4em}
.toc-title{font-size:.8rem;letter-spacing:.5px;text-transform:uppercase;opacity:.75}
.toc-list{list-style:none;padding-left:0;margin:0 0 .75rem 0}
.toc-list ul{list-style:none;margin:.25rem 0 .25rem .9rem;padding-left:.6rem;border-left:1px solid rgba(0,0,0,0.08)}
.dark .toc-list ul{border-color:rgba(255,255,255,0.15)}
.toc-list a{text-decoration:none;color:var(--c-text-secondary)}
.toc-list a:hover{color:var(--c-accent,#2563eb)}
/* Chat */
.chat-messages{font-family:system-ui,Segoe UI,Arial,sans-serif}
.chat-msg{margin-bottom:12px;display:flex;gap:8px;align-items:flex-start}
.chat-avatar{width:28px;height:28px;border-radius:50%;flex-shrink:0;display:flex;align-items:center;justify-content:center;font-size:.7rem;font-weight:600;background:#e2e8f0;color:#334155}
.dark .chat-avatar{background:#334155;color:#e2e8f0}
.chat-bubble{max-width:75%;padding:8px 10px;border-radius:10px;position:relative;white-space:pre-wrap;word-break:break-word;background:#f1f5f9;color:#0f172a;font-size:.8rem;line-height:1.25}
.dark .chat-bubble{background:#1e293b;color:#f1f5f9}
.chat-msg.user .chat-bubble{background:#dbeafe;color:#1e3a8a}
.dark .chat-msg.user .chat-bubble{background:#1e3a8a;color:#dbeafe}
.chat-msg.assistant .chat-bubble{background:#f0fdf4;color:#065f46}
.dark .chat-msg.assistant .chat-bubble{background:#064e3b;color:#d1fae5}
.chat-meta{font-size:.65rem;opacity:.6;margin-top:2px}
.chat-refs{margin-top:6px;padding:6px 8px;border-left:3px solid #3b82f6;background:#f1f5f9;font-size:.65rem;line-height:1.2}
.dark .chat-refs{background:#1e293b;border-color:#3b82f6}
.chat-refs h6{margin:0 0 4px;font-size:.6rem;letter-spacing:.5px;text-transform:uppercase;opacity:.7}
.chat-refs.collapsed{max-height:0;overflow:hidden;padding-top:0;padding-bottom:0;margin-top:0;border:none}
.chat-ref-toggle{cursor:pointer;font-size:.65rem;color:#2563eb;display:inline-block;margin-top:4px}
.chat-ref-toggle:hover{text-decoration:underline}
.chat-retry-btn{background:#ef4444;color:#fff;border:none;border-radius:4px;padding:2px 6px;font-size:.6rem;cursor:pointer;margin-left:6px}
.chat-retry-btn:hover{background:#dc2626}
.chat-mask{position:absolute;inset:0;background:rgba(255,255,255,0.85);backdrop-filter:blur(4px);border-radius:0.75rem;z-index:10;padding:1rem}
.dark .chat-mask{background:rgba(15,23,42,0.82)}
#sec-chat{position:relative}
.chat-locked #chat-messages,.chat-locked #q,.chat-locked #btn-ask,.chat-locked #btn-clear-chat{filter:blur(2px);pointer-events:none;user-select:none}
.chat-stream-cursor{display:inline-block;width:6px;background:#10b981;animation:blink .9s steps(2,start) infinite;height:1em;vertical-align:bottom;margin-left:2px}
@keyframes blink{0%,50%{opacity:1}50.01%,100%{opacity:0}}
.prose h4 { font-size:1.05rem; margin:1.1em 0 .45em; }
.prose h5 { font-size:.95rem; margin:1em 0 .4em; text-transform:uppercase; letter-spacing:.5px; opacity:.9; }
.prose h6 { font-size:.85rem; margin:.9em 0 .35em; text-transform:uppercase; letter-spacing:.5px; opacity:.75; }
.prose > h1:first-child, .prose > h2:first-child, .prose > h3:first-child { margin-top:0; }
:root[data-theme="dark"] .prose h1 { border-bottom-color: rgba(148,163,184,0.25); }
:root[data-theme="dark"] .prose h2 { border-bottom-color: rgba(148,163,184,0.18); }

/* KaTeX adjustments */
.prose .katex-display { overflow-x:auto; padding:0.4em 0.6em; }
.prose .katex-display > .katex { font-size: 1.05em; }
:root[data-theme="dark"] .katex { color: #f3f4f6; }
:root[data-theme="dark"] .katex .mord { color: #f3f4f6; }

/* Subtle scrollbar styling */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-thumb { background: rgba(100,116,139,0.35); border-radius: 8px; }
::-webkit-scrollbar-thumb:hover { background: rgba(100,116,139,0.55); }
::-webkit-scrollbar-track { background: transparent; }
:root[data-theme="dark"] ::-webkit-scrollbar-thumb { background: rgba(148,163,184,0.45); }
:root[data-theme="dark"] ::-webkit-scrollbar-thumb:hover { background: rgba(148,163,184,0.65); }

/* Subtle loading spinner utility */
.spinner {
  width: 16px; height: 16px; border-radius: 9999px;
  border: 2px solid rgba(0,0,0,0.1);
  border-top-color: var(--primary);
  animation: spin 900ms linear infinite;
}

/* Status dot */
.status-wrap { position: fixed; left: 16px; top: 12px; display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--muted) }
.status-dot { width: 12px; height: 12px; border-radius: 50%; box-shadow: 0 0 0 2px rgba(2,6,23,.04) inset }
.status-dot.ok { background: #10b981; }
.status-dot.warn { background: #f59e0b; }
.status-dot.err { background: #ef4444; }

@keyframes spin { to { transform: rotate(360deg) } }
@keyframes fadeIn { from { opacity: 0 } to { opacity: 1 } }
@keyframes floatIn {
  from { opacity: 0; transform: translateY(6px) }
  to   { opacity: 1; transform: translateY(0) }
}

/* Respect reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

@media (max-width: 640px) {
  .structure-unit-head {
    flex-direction: column;
  }

  .chapter-item {
    grid-template-columns: 1fr;
  }

  .chapter-checklist {
    grid-template-columns: 1fr;
  }
}

/* ── Modal system ── */
.modal-overlay {
  position: fixed; inset: 0; z-index: 100;
  background: rgba(0,0,0,0.45);
  backdrop-filter: blur(4px);
  display: flex; align-items: center; justify-content: center;
  animation: fadeIn var(--transition-fast) var(--ease-smooth);
}
.modal-overlay.hidden { display: none; }
.modal-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 1rem;
  padding: 1.5rem;
  width: 90%; max-width: 420px;
  box-shadow: 0 24px 48px rgba(0,0,0,0.18);
  animation: floatIn var(--transition-normal) var(--ease-smooth);
}
.modal-card input, .modal-card select {
  background: var(--bg); color: var(--text); border: 1px solid var(--border);
  border-radius: 0.375rem; padding: 0.5rem 0.75rem; width: 100%; font-size: 0.875rem;
}
.modal-card input:focus, .modal-card select:focus {
  outline: none;
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--ring) 35%, transparent);
  border-color: color-mix(in srgb, var(--ring) 60%, transparent);
}

/* ── Skeleton loading ── */
.skeleton {
  background: linear-gradient(90deg, var(--border) 25%, transparent 50%, var(--border) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: 6px;
}
.skeleton-line { height: 12px; margin-bottom: 8px; }
.skeleton-line:last-child { width: 60%; }
.skeleton-circle { width: 40px; height: 40px; border-radius: 50%; }

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ── Loading button state ── */
.btn-loading { position: relative; pointer-events: none; opacity: 0.75; }
.btn-loading::after {
  content: ''; position: absolute; right: 8px; top: 50%; transform: translateY(-50%);
  width: 14px; height: 14px; border-radius: 50%;
  border: 2px solid rgba(255,255,255,0.3);
  border-top-color: #fff;
  animation: spin 800ms linear infinite;
}

/* ── Theme transition (smooth dark/light switch) ── */
html { transition: background var(--transition-slow), color var(--transition-slow); }
.rr-card { transition: background var(--transition-slow), border-color var(--transition-slow), box-shadow var(--transition-normal) var(--ease-smooth); }

/* ── Responsive tables ── */
.table-responsive { overflow-x: auto; -webkit-overflow-scrolling: touch; }
.table-responsive table { min-width: 600px; }

/* ── Responsive helpers ── */
@media (max-width: 640px) {
  .status-wrap { left: 12px; top: 56px; }
  .topbar-spacer { height: 60px; }
  .topbar .brand-logo { height: 50px; }
}

/* ── Dark mode border for login-mask ── */
:root[data-theme="dark"] #login-mask {
  background: rgba(30,40,60,0.9);
  border-color: rgba(148,163,184,0.2);
  color: var(--text);
}

/* ── Improved empty state ── */
.empty {
  display: flex; align-items: center; gap: 10px; color: var(--muted);
  padding: 1rem 0;
}
.empty svg { width: 28px; height: 28px; opacity: 0.5; flex-shrink: 0; }
.empty.flex-col { flex-direction: column; gap: 6px; }

/* ── File bubble hover & interaction ── */
[data-file-id] {
  transition: transform var(--transition-fast) var(--ease-smooth),
              box-shadow var(--transition-fast) var(--ease-smooth),
              background var(--transition-fast);
}
[data-file-id]:hover {
  transform: scale(1.04);
  box-shadow: 0 4px 12px rgba(5,150,105,0.18);
}
[data-file-id]:active { transform: scale(0.98); }

/* ── Touch target minimum sizes ── */
.topbar button, .topbar .lang-btn {
  min-height: 36px; min-width: 36px;
  display: inline-flex; align-items: center; justify-content: center;
}
@media (max-width: 640px) {
  .topbar button { min-height: 40px; min-width: 40px; }
}

/* ── Draft saved indicator ── */
#draft-status {
  opacity: 0; transition: opacity var(--transition-fast);
  font-size: 0.7rem; color: var(--muted);
}
#draft-status.show { opacity: 1; }

/* ── History search loading ── */
#history-box.loading { opacity: 0.5; pointer-events: none; transition: opacity var(--transition-fast); }

/* ── Keyboard shortcut hint ── */
.shortcut-hint {
  font-size: 0.65rem; color: var(--muted); opacity: 0.7;
  display: inline-flex; align-items: center; gap: 3px;
}
.shortcut-hint kbd {
  background: var(--border); border-radius: 3px; padding: 1px 4px;
  font-family: inherit; font-size: 0.6rem; border: 1px solid var(--border);
}

body.page-surface {
  min-height: 100vh;
  background:
    radial-gradient(circle at top left, rgba(5,150,105,0.16), transparent 28%),
    radial-gradient(circle at top right, rgba(37,99,235,0.14), transparent 26%),
    linear-gradient(180deg, color-mix(in srgb, var(--bg) 85%, white 15%) 0%, var(--bg) 48%, color-mix(in srgb, var(--bg) 92%, var(--card-bg) 8%) 100%);
}

:root[data-theme="dark"] body.page-surface {
  background:
    radial-gradient(circle at top left, rgba(16,185,129,0.16), transparent 28%),
    radial-gradient(circle at top right, rgba(56,189,248,0.12), transparent 24%),
    linear-gradient(180deg, #08101d 0%, #0b1220 52%, #111827 100%);
}

.page-wrap {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 1rem 2rem;
}

.shell-topbar .page-wrap {
  padding-bottom: 0;
}

.shell-topbar__row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 64px;
}

.shell-brand {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  text-decoration: none;
  min-width: 0;
}

.shell-brand-logo {
  height: 44px;
  width: auto;
  flex-shrink: 0;
}

.shell-brand__text {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.shell-brand__name {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
}

.shell-brand__tag {
  font-size: 0.72rem;
  color: var(--muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 20rem;
}

.shell-counter {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 0.45rem 0.9rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: color-mix(in srgb, var(--card-bg) 84%, var(--primary) 16%);
  color: var(--text);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
  box-shadow: 0 8px 18px rgba(2, 6, 23, 0.08);
}

.shell-counter.is-loading {
  color: var(--muted);
}

.shell-counter--compact {
  min-height: 32px;
  padding: 0.3rem 0.72rem;
  font-size: 0.72rem;
  box-shadow: none;
}

:root[data-theme="dark"] .shell-counter {
  background: color-mix(in srgb, var(--card-bg) 88%, var(--primary-600) 12%);
  border-color: rgba(148, 163, 184, 0.2);
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.24);
}

.shell-utility {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.shell-inline-link {
  font-size: 0.82rem;
  color: var(--secondary);
  text-decoration: none;
  white-space: nowrap;
}

.shell-inline-link:hover {
  text-decoration: underline;
}

.shell-icon-btn {
  width: 38px;
  height: 38px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--card-bg);
  color: var(--text);
}

.shell-lang {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.2rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--card-bg);
}

.shell-lang button {
  min-width: 42px;
  padding: 0.35rem 0.65rem;
  border-radius: 999px;
  font-size: 0.78rem;
}

.shell-lang button.active {
  background: var(--text);
  color: var(--card-bg);
}

.shell-nav-strip {
  padding: 0.9rem 0 1.2rem;
}

.shell-nav-scroll {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  overflow-x: auto;
  padding-bottom: 0.1rem;
}

.shell-pill {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 0.55rem 1rem;
  border-radius: 999px;
  background: color-mix(in srgb, var(--card-bg) 82%, var(--bg));
  border: 1px solid var(--border);
  text-decoration: none;
  font-weight: 700;
  color: var(--muted);
  white-space: nowrap;
}

.shell-pill.is-active {
  background: var(--text);
  color: var(--card-bg);
  border-color: transparent;
}

.page-hero {
  display: flex;
  justify-content: space-between;
  gap: 1.25rem;
  align-items: flex-start;
  margin-bottom: 1.4rem;
  padding: 1.4rem 1.35rem;
  border-radius: 1.5rem;
  background: linear-gradient(135deg, color-mix(in srgb, var(--card-bg) 82%, var(--primary) 18%) 0%, color-mix(in srgb, var(--card-bg) 92%, var(--secondary) 8%) 100%);
  border: 1px solid var(--border);
  box-shadow: 0 18px 32px var(--shadow-color);
}

.page-hero__copy {
  max-width: 44rem;
}

.page-kicker {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--secondary);
  font-weight: 700;
}

.page-title {
  font-size: clamp(1.85rem, 2.6vw, 3rem);
  line-height: 1.05;
  font-weight: 800;
  letter-spacing: -0.03em;
}

.page-subtitle {
  margin-top: 0.65rem;
  max-width: 46rem;
  color: var(--muted);
  font-size: 0.97rem;
  line-height: 1.65;
}

.page-hero__actions {
  display: flex;
  gap: 0.7rem;
  flex-wrap: wrap;
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.9rem;
  margin-bottom: 1.4rem;
}

.stat-card {
  padding: 1rem 1rem 1.1rem;
  border-radius: 1.2rem;
  background: color-mix(in srgb, var(--card-bg) 92%, var(--bg));
  border: 1px solid var(--border);
  box-shadow: 0 18px 32px var(--shadow-color);
}

.stat-card__label {
  font-size: 0.76rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.stat-card__value {
  margin-top: 0.4rem;
  font-size: 1.55rem;
  font-weight: 750;
}

.workflow-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-bottom: 1.4rem;
}

.workflow-card {
  position: relative;
  padding: 1.25rem;
  border-radius: 1.35rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  box-shadow: 0 18px 32px var(--shadow-color);
  overflow: hidden;
}

.workflow-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--secondary), #f59e0b);
}

.workflow-card__step {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.workflow-card__title {
  margin-top: 0.4rem;
  font-size: 1.15rem;
  font-weight: 700;
}

.workflow-card__desc {
  margin-top: 0.45rem;
  color: var(--muted);
  line-height: 1.6;
  min-height: 3.2em;
}

.workflow-card__meta {
  margin-top: 0.85rem;
  font-size: 0.82rem;
  color: var(--secondary);
}

.workflow-card__cta {
  margin-top: 1rem;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.78rem 1rem;
  border-radius: 999px;
  background: var(--text);
  color: var(--card-bg);
  text-decoration: none;
  font-weight: 700;
}

.workflow-card__cta:hover {
  color: var(--card-bg);
  transform: translateY(-1px);
}

.panel {
  padding: 1.25rem;
  border-radius: 1.35rem;
  background: color-mix(in srgb, var(--card-bg) 94%, white 6%);
  border: 1px solid var(--border);
  box-shadow: 0 18px 32px var(--shadow-color);
}

.panel + .panel {
  margin-top: 1rem;
}

.panel-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

.panel-title {
  font-size: 1rem;
  font-weight: 700;
}

.panel-copy {
  color: var(--muted);
  line-height: 1.6;
  font-size: 0.92rem;
}

.page-grid {
  display: grid;
  gap: 1rem;
}

.page-grid--two {
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  align-items: start;
}

.page-grid--review {
  grid-template-columns: minmax(0, 0.95fr) minmax(0, 1.05fr);
  align-items: start;
}

.page-grid--chat {
  grid-template-columns: minmax(0, 0.78fr) minmax(0, 1.22fr);
  align-items: start;
}

.toolbar-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.context-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.85rem;
}

.context-grid--wide {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.field-stack {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  min-width: 0;
}

.field-label {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  font-weight: 700;
}

.context-summary {
  padding: 0.95rem 1rem;
  border-radius: 1rem;
  background: color-mix(in srgb, var(--card-bg) 88%, var(--bg));
  border: 1px solid var(--border);
}

.context-summary--wide {
  grid-column: span 2;
}

.context-summary__value {
  font-size: 0.98rem;
  font-weight: 700;
  line-height: 1.55;
}

.primary-btn,
.soft-btn,
.ghost-btn,
.danger-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  min-height: 42px;
  padding: 0.65rem 1rem;
  border-radius: 999px;
  font-size: 0.88rem;
  font-weight: 700;
  border: 1px solid transparent;
  text-decoration: none;
  cursor: pointer;
}

.primary-btn {
  background: linear-gradient(135deg, var(--primary), #10b981);
  color: #fff;
  box-shadow: 0 10px 18px rgba(5,150,105,0.24);
}

.primary-btn:hover {
  color: #fff;
}

.soft-btn {
  background: color-mix(in srgb, var(--secondary) 14%, var(--card-bg));
  color: var(--text);
  border-color: var(--border);
}

.ghost-btn {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}

.ghost-btn.is-active,
.soft-btn.is-active {
  color: var(--secondary);
  border-color: rgba(37,99,235,0.3);
  background: color-mix(in srgb, var(--secondary) 14%, var(--card-bg));
}

.danger-btn {
  background: rgba(239,68,68,0.12);
  color: #b91c1c;
  border-color: rgba(239,68,68,0.2);
}

.primary-btn:hover,
.soft-btn:hover,
.ghost-btn:hover,
.danger-btn:hover {
  transform: translateY(-1px);
}

.primary-btn:disabled,
.soft-btn:disabled,
.ghost-btn:disabled,
.danger-btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
  transform: none !important;
  box-shadow: none;
}

.input-field,
.text-area,
.search-input,
.select-field {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 1rem;
  background: var(--card-bg);
  color: var(--text);
  padding: 0.85rem 1rem;
}

.input-field:focus,
.text-area:focus,
.search-input:focus,
.select-field:focus {
  outline: none;
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--ring) 35%, transparent);
  border-color: color-mix(in srgb, var(--ring) 60%, transparent);
}

.text-area {
  min-height: 220px;
  resize: vertical;
}

.search-input,
.select-field {
  min-height: 42px;
}

.helper-text {
  font-size: 0.82rem;
  color: var(--muted);
  line-height: 1.6;
}

.note-box {
  padding: 0.85rem 1rem;
  border-radius: 1rem;
  background: color-mix(in srgb, var(--bg) 70%, var(--card-bg));
  border: 1px dashed var(--border);
  color: var(--muted);
}

.source-list {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.source-card {
  padding: 1rem;
  border-radius: 1.1rem;
  background: color-mix(in srgb, var(--card-bg) 90%, var(--bg));
  border: 1px solid var(--border);
}

.source-card--selected {
  border-color: rgba(5,150,105,0.45);
  box-shadow: 0 0 0 3px rgba(16,185,129,0.12);
}

.source-card__meta {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 0.6rem;
  font-size: 0.78rem;
  color: var(--muted);
}

.source-badge {
  display: inline-flex;
  align-items: center;
  padding: 0.22rem 0.55rem;
  border-radius: 999px;
  background: color-mix(in srgb, var(--secondary) 12%, var(--card-bg));
  color: var(--secondary);
  font-weight: 700;
}

.source-card__title {
  font-size: 0.98rem;
  font-weight: 700;
  line-height: 1.45;
}

.source-card__preview {
  margin-top: 0.5rem;
  color: var(--muted);
  font-size: 0.85rem;
  line-height: 1.55;
}

.source-card__actions {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin-top: 0.85rem;
}

.structure-unit-card {
  padding: 1rem;
  border-radius: 1rem;
  border: 1px solid var(--border);
  background: color-mix(in srgb, var(--card-bg) 90%, var(--bg));
}

.structure-unit-card + .structure-unit-card {
  margin-top: 0.85rem;
}

.structure-unit-head {
  display: flex;
  gap: 0.75rem;
  align-items: flex-start;
}

.chapter-list {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  margin: 0.85rem 0;
}

.chapter-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 0.65rem;
  align-items: center;
}

.mapping-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 0.35rem;
}

.mapping-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.38rem 0.65rem;
  border-radius: 999px;
  background: color-mix(in srgb, var(--primary) 8%, var(--card-bg));
  border: 1px solid color-mix(in srgb, var(--primary) 20%, var(--border));
  font-size: 0.78rem;
}

.mapping-chip__tag {
  color: var(--muted);
  font-size: 0.7rem;
}

.mapping-editor {
  margin-top: 0.85rem;
  padding: 0.9rem;
  border-radius: 1rem;
  background: color-mix(in srgb, var(--bg) 76%, var(--card-bg));
  border: 1px solid var(--border);
}

.chapter-group {
  padding: 0.95rem 1rem;
  border-radius: 1rem;
  border: 1px solid var(--border);
  background: color-mix(in srgb, var(--card-bg) 92%, var(--bg));
}

.chapter-group + .chapter-group {
  margin-top: 0.75rem;
}

.chapter-group__title {
  margin-bottom: 0.7rem;
  font-weight: 700;
  line-height: 1.4;
}

.chapter-checklist {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 0.65rem;
}

.chapter-option {
  display: flex;
  gap: 0.55rem;
  align-items: flex-start;
  padding: 0.7rem 0.8rem;
  border-radius: 0.9rem;
  border: 1px solid var(--border);
  background: color-mix(in srgb, var(--card-bg) 86%, var(--bg));
  cursor: pointer;
}

.chapter-option input {
  margin-top: 0.15rem;
}

.history-card__chips {
  margin-top: 0.75rem;
}

.chip-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.source-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.55rem 0.8rem;
  border-radius: 999px;
  background: color-mix(in srgb, var(--card-bg) 82%, var(--bg));
  border: 1px solid var(--border);
  font-size: 0.82rem;
}

.source-chip__tag {
  font-size: 0.72rem;
  color: var(--muted);
}

.segmented-group {
  display: inline-flex;
  gap: 0.35rem;
  padding: 0.3rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: color-mix(in srgb, var(--card-bg) 88%, var(--bg));
}

.segmented-btn {
  min-width: 72px;
  padding: 0.52rem 0.85rem;
  border-radius: 999px;
  font-size: 0.83rem;
  font-weight: 700;
  color: var(--muted);
}

.segmented-btn.is-active {
  background: var(--text);
  color: var(--card-bg);
}

.segmented-btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.progress-card {
  margin-top: 1rem;
  padding: 0.9rem 1rem;
  border-radius: 1rem;
  background: color-mix(in srgb, var(--bg) 78%, var(--card-bg));
  border: 1px solid var(--border);
}

.progress-track {
  width: 100%;
  height: 10px;
  border-radius: 999px;
  background: rgba(148,163,184,0.2);
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  transition: width 0.25s ease;
}

.result-frame {
  min-height: 420px;
  padding: 1.25rem;
  border-radius: 1.2rem;
  background: color-mix(in srgb, var(--card-bg) 94%, white 6%);
  border: 1px solid var(--border);
  overflow: auto;
}

.empty-state {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 140px;
  padding: 1.25rem;
  border-radius: 1rem;
  border: 1px dashed var(--border);
  color: var(--muted);
  text-align: center;
  line-height: 1.6;
}

.review-summary {
  padding: 1rem;
  border-radius: 1rem;
  background: color-mix(in srgb, var(--card-bg) 88%, var(--bg));
  border: 1px solid var(--border);
}

.review-summary__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  font-size: 0.8rem;
  color: var(--muted);
  margin-bottom: 0.55rem;
}

.review-summary__preview {
  color: var(--text);
  line-height: 1.7;
  display: -webkit-box;
  -webkit-line-clamp: 5;
  -webkit-box-orient: vertical;
  overflow: hidden;
  white-space: pre-wrap;
}

.flow-dock {
  position: sticky;
  top: 4.75rem;
  z-index: 8;
  margin-bottom: 1rem;
  padding: 1rem;
  border-radius: 1rem;
  border: 1px solid var(--border);
  background: color-mix(in srgb, var(--card-bg) 94%, var(--bg));
  box-shadow: 0 14px 28px var(--shadow-color);
}

.flow-dock.is-ready {
  border-color: color-mix(in srgb, var(--primary) 35%, var(--border));
}

.flow-dock__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.flow-pill {
  display: inline-flex;
  align-items: center;
  padding: 0.45rem 0.8rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: color-mix(in srgb, var(--bg) 78%, var(--card-bg));
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1.2;
}

.flow-dock__copy {
  margin-top: 0.72rem;
  color: var(--text);
  line-height: 1.6;
}

.flow-dock__preview {
  margin-top: 0.6rem;
  color: var(--muted);
  line-height: 1.55;
  white-space: pre-wrap;
  word-break: break-word;
}

.history-list {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.history-card {
  padding: 1rem;
  border-radius: 1.1rem;
  background: color-mix(in srgb, var(--card-bg) 92%, var(--bg));
  border: 1px solid var(--border);
}

.history-card__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  font-size: 0.78rem;
  color: var(--muted);
  margin-bottom: 0.5rem;
}

.history-card__title {
  font-size: 1rem;
  font-weight: 700;
}

.history-card__preview {
  margin-top: 0.45rem;
  color: var(--muted);
  line-height: 1.6;
}

.chat-log {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  min-height: 420px;
  max-height: 620px;
  overflow: auto;
  padding-right: 0.15rem;
}

.chat-entry {
  display: flex;
}

.chat-entry--user {
  justify-content: flex-end;
}

.chat-entry__bubble {
  max-width: 88%;
  padding: 0.9rem 1rem;
  border-radius: 1.15rem;
  background: color-mix(in srgb, var(--card-bg) 92%, var(--bg));
  border: 1px solid var(--border);
  box-shadow: 0 10px 20px var(--shadow-color);
}

.chat-entry--user .chat-entry__bubble {
  background: color-mix(in srgb, var(--secondary) 14%, var(--card-bg));
}

.chat-entry--assistant .chat-entry__bubble {
  background: color-mix(in srgb, var(--primary) 10%, var(--card-bg));
}

.chat-entry__refs {
  margin-top: 0.8rem;
  padding-top: 0.8rem;
  border-top: 1px solid var(--border);
  font-size: 0.82rem;
  color: var(--muted);
}

.chat-entry__refs summary {
  cursor: pointer;
  color: var(--secondary);
  font-weight: 600;
}

.chat-entry__refs ol {
  margin: 0.55rem 0 0 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.chat-entry__refs li {
  line-height: 1.55;
}

.app-footer {
  margin: 1.6rem auto 2rem;
  max-width: 1120px;
  padding: 0 1rem;
  color: var(--muted);
  font-size: 0.8rem;
  text-align: center;
}

.muted-inline {
  color: var(--muted);
  font-size: 0.84rem;
}

@media (max-width: 980px) {
  .page-grid--two,
  .page-grid--review,
  .page-grid--chat,
  .workflow-grid,
  .stat-grid,
  .context-grid,
  .context-grid--wide {
    grid-template-columns: 1fr;
  }

  .shell-topbar__row {
    flex-wrap: wrap;
  }

  .shell-utility {
    width: 100%;
    justify-content: space-between;
  }

  .shell-counter {
    margin-left: auto;
  }

  .page-hero {
    flex-direction: column;
  }

  .page-hero__actions {
    width: 100%;
  }

  .context-summary--wide {
    grid-column: span 1;
  }

  .flow-dock {
    position: static;
    top: auto;
  }
}

@media (max-width: 640px) {
  .shell-brand__tag {
    display: none;
  }

  .shell-utility {
    gap: 0.5rem;
  }

  .shell-counter {
    width: 100%;
    order: 3;
    margin-left: 0;
  }

  .shell-counter--compact {
    width: auto;
    order: 0;
  }

  .shell-inline-link {
    font-size: 0.76rem;
  }

  .page-wrap {
    padding: 0 0.85rem 2rem;
  }

  .page-hero {
    padding: 1.15rem;
    border-radius: 1.2rem;
  }

  .page-title {
    font-size: 1.8rem;
  }

  .panel {
    padding: 1rem;
  }

  .chat-log {
    min-height: 320px;
    max-height: none;
  }

  .chat-entry__bubble {
    max-width: 100%;
  }
}

/* ══════════════════════════════════════════════════════
   Course Gallery (workspace) & Course Header (inner pages)
   ══════════════════════════════════════════════════════ */

/* Course gallery grid */
.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.25rem;
  margin-top: 1.5rem;
}

/* Course card */
.course-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 0.875rem;
  overflow: hidden;
  box-shadow: 0 2px 8px var(--shadow-color);
  transition: transform var(--transition-fast) var(--ease-smooth),
              box-shadow var(--transition-fast) var(--ease-smooth);
  display: flex; flex-direction: column;
}
.course-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(2,6,23,0.12);
}
:root[data-theme="dark"] .course-card:hover {
  box-shadow: 0 8px 24px rgba(0,0,0,0.45);
}

.course-card__banner {
  height: 72px;
  display: flex; align-items: flex-end; padding: 0.625rem 0.875rem;
}

.course-card__body {
  padding: 0.875rem;
  flex: 1;
  display: flex; flex-direction: column; gap: 0.35rem;
}
.course-card__name {
  font-size: 1rem; font-weight: 600; color: var(--text); line-height: 1.3;
}
.course-card__meta {
  font-size: 0.75rem; color: var(--muted);
}

.course-card__footer {
  padding: 0.625rem 0.875rem;
  border-top: 1px solid var(--border);
  display: flex; gap: 0.5rem; justify-content: flex-end;
}

.course-card__action {
  flex: 1 1 0;
}

/* Subject banner colours */
.course-banner--math     { background: linear-gradient(135deg, #6366f1 0%, #4f46e5 100%); }
.course-banner--physics  { background: linear-gradient(135deg, #0ea5e9 0%, #0284c7 100%); }
.course-banner--chemistry{ background: linear-gradient(135deg, #10b981 0%, #059669 100%); }
.course-banner--biology  { background: linear-gradient(135deg, #22c55e 0%, #16a34a 100%); }
.course-banner--chinese  { background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%); }
.course-banner--english  { background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%); }
.course-banner--history  { background: linear-gradient(135deg, #e97316 0%, #c2410c 100%); }
.course-banner--geography{ background: linear-gradient(135deg, #14b8a6 0%, #0d9488 100%); }
.course-banner--politics { background: linear-gradient(135deg, #ef4444 0%, #b91c1c 100%); }
.course-banner--cs       { background: linear-gradient(135deg, #8b5cf6 0%, #7c3aed 100%); }
.course-banner--economics{ background: linear-gradient(135deg, #f97316 0%, #ea580c 100%); }
.course-banner--other    { background: linear-gradient(135deg, #94a3b8 0%, #64748b 100%); }

/* Subject badge in cards and course header */
.course-badge {
  display: inline-flex; align-items: center;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  font-size: 0.7rem; font-weight: 600;
  color: #fff; letter-spacing: 0.3px;
  white-space: nowrap;
}
.course-badge--math     { background: #4f46e5; }
.course-badge--physics  { background: #0284c7; }
.course-badge--chemistry{ background: #059669; }
.course-badge--biology  { background: #16a34a; }
.course-badge--chinese  { background: #d97706; }
.course-badge--english  { background: #2563eb; }
.course-badge--history  { background: #c2410c; }
.course-badge--geography{ background: #0d9488; }
.course-badge--politics { background: #b91c1c; }
.course-badge--cs       { background: #7c3aed; }
.course-badge--economics{ background: #ea580c; }
.course-badge--other    { background: #64748b; }

/* New course dialog */
.new-course-dialog {
  border: 1px solid var(--border);
  border-radius: 1rem;
  padding: 1.5rem;
  width: 90%; max-width: 420px;
  background: var(--card-bg);
  color: var(--text);
  box-shadow: 0 24px 48px rgba(0,0,0,0.18);
}
.new-course-dialog::backdrop {
  background: rgba(0,0,0,0.4);
  backdrop-filter: blur(4px);
}
.new-course-dialog input,
.new-course-dialog select {
  background: var(--bg); color: var(--text); border: 1px solid var(--border);
  border-radius: 0.375rem; padding: 0.5rem 0.75rem; width: 100%; font-size: 0.875rem;
}
.new-course-dialog input:focus,
.new-course-dialog select:focus {
  outline: none;
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--ring) 35%, transparent);
  border-color: color-mix(in srgb, var(--ring) 60%, transparent);
}

/* Course header (sticky bar on inner pages) */
.course-header {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 40;
  padding: 0 0;
}
.course-header__inner {
  max-width: 1200px; margin: 0 auto; padding: 0 1.5rem;
  display: flex; align-items: center; gap: 1rem;
}
.course-header__context {
  display: flex; align-items: center; gap: 0.625rem;
  flex: 0 0 auto;
  padding: 0.6rem 0;
}
.course-back-btn {
  font-size: 0.8rem; color: var(--muted); text-decoration: none;
  display: inline-flex; align-items: center; gap: 0.25rem;
  padding: 0.25rem 0.5rem;
  border-radius: 0.375rem;
  transition: background var(--transition-fast), color var(--transition-fast);
}
.course-back-btn:hover { background: color-mix(in srgb, var(--bg) 60%, var(--primary) 40%); color: var(--primary); }
.course-header__name {
  font-weight: 600; font-size: 0.9rem; color: var(--text);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 200px;
}
.course-context-divider { width: 1px; height: 18px; background: var(--border); flex-shrink: 0; }

/* Course tabs */
.course-tabs {
  display: flex; align-items: stretch; flex: 1; gap: 0;
  overflow-x: auto; scrollbar-width: none;
}
.course-tabs::-webkit-scrollbar { display: none; }
.course-tab {
  display: inline-flex; align-items: center; padding: 0 1.1rem;
  font-size: 0.85rem; color: var(--muted); text-decoration: none;
  border-bottom: 2px solid transparent; white-space: nowrap;
  height: 44px; transition: color var(--transition-fast), border-color var(--transition-fast);
}
.course-tab:hover { color: var(--text); }
.course-tab--active {
  color: var(--primary); border-bottom-color: var(--primary); font-weight: 600;
}
:root[data-theme="dark"] .course-tab--active { color: #34d399; border-bottom-color: #34d399; }

/* No-course banner on inner pages */
.no-course-banner {
  display: flex; align-items: center; gap: 0.75rem;
  background: color-mix(in srgb, var(--card-bg) 80%, #f59e0b 20%);
  border: 1px solid color-mix(in srgb, transparent 60%, #f59e0b 40%);
  border-radius: 0.75rem; padding: 1rem 1.25rem;
  margin-bottom: 1.25rem;
}
.no-course-banner__icon { font-size: 1.4rem; flex-shrink: 0; }
.no-course-banner__text { flex: 1; }
.no-course-banner__title { font-weight: 600; font-size: 0.9rem; color: var(--text); }
.no-course-banner__sub { font-size: 0.8rem; color: var(--muted); margin-top: 0.15rem; }

@media (max-width: 640px) {
  .course-grid { grid-template-columns: 1fr; }
  .course-header__inner { padding: 0 1rem; gap: 0.5rem; }
  .course-header__name { max-width: 120px; }
  .course-tab { padding: 0 0.75rem; font-size: 0.78rem; }
}