:root {
  --primary: #4f46e5;
  --primary-dark: #4338ca;
  --nav-bg: #1e1b4b;
  --bg: #f4f5f7;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --border: #e5e7eb;
  --success: #16a34a;
  --error: #dc2626;
  --warning: #d97706;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, Roboto, Arial, sans-serif;
  background: #eef2ff;
  background: linear-gradient(160deg, #e0e7ff 0%, #fae8ff 45%, #cffafe 100%) fixed;
  color: var(--text);
  line-height: 1.5;
}

/* Background themes (selectable in Settings) */
body.theme-ocean { background: linear-gradient(160deg, #dbeafe 0%, #bae6fd 50%, #a5f3fc 100%) fixed; }
body.theme-sunset { background: linear-gradient(160deg, #fef3c7 0%, #fed7aa 45%, #fecaca 100%) fixed; }
body.theme-forest { background: linear-gradient(160deg, #d1fae5 0%, #bbf7d0 50%, #99f6e4 100%) fixed; }
body.theme-rose { background: linear-gradient(160deg, #fce7f3 0%, #fbcfe8 50%, #f9a8d4 100%) fixed; }
body.theme-midnight { background: linear-gradient(160deg, #1e293b 0%, #334155 50%, #475569 100%) fixed; }
body.theme-school3d { background: linear-gradient(rgba(255,255,255,0.86), rgba(255,255,255,0.86)), url('/static/bg-school.svg') center / cover fixed no-repeat; }
body.theme-classroom3d { background: linear-gradient(rgba(255,255,255,0.86), rgba(255,255,255,0.86)), url('/static/bg-classroom.svg') center / cover fixed no-repeat; }
body.theme-books3d { background: linear-gradient(rgba(255,255,255,0.86), rgba(255,255,255,0.86)), url('/static/bg-books.svg') center / cover fixed no-repeat; }
body.has-bg { background-size: cover; background-position: center; background-attachment: fixed; }

/* Navbar */
.navbar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  background: linear-gradient(90deg, #1e1b4b, #3730a3 50%, #1e1b4b);
  color: #fff;
  padding: 0.75rem 1.25rem;
  position: sticky;
  top: 0;
  z-index: 1000;
}
.navbar .brand { font-weight: 700; font-size: 1.15rem; margin-right: 1rem; }
.nav-links { display: flex; flex-wrap: wrap; gap: 0.15rem; }
.nav-links a {
  color: #e0e2ff;
  text-decoration: none;
  padding: 0.4rem 0.7rem;
  border-radius: 6px;
  font-size: 0.92rem;
}
.nav-links a:hover { background: rgba(255,255,255,0.12); }
.nav-links a.active { background: rgba(255,255,255,0.2); color: #fff; }
.nav-right { margin-left: auto; display: flex; align-items: center; gap: 0.7rem; }
.nav-right .user { color: #c7d2fe; font-size: 0.9rem; }
.nav-right a { color: #e0e2ff; text-decoration: none; font-size: 0.9rem; }
.nav-right a.lang-toggle {
  border: 1px solid rgba(255,255,255,0.4);
  padding: 0.2rem 0.55rem;
  border-radius: 6px;
  font-weight: 600;
}
.nav-right a.logout { color: #fca5a5; }

/* Layout */
.container { max-width: 1080px; margin: 1.5rem auto; padding: 0 1.25rem; }

h1 { font-size: 1.6rem; margin: 0 0 0.5rem; }
h2 { font-size: 1.2rem; margin: 1.75rem 0 0.75rem; }
h3 { font-size: 1.05rem; margin: 1.25rem 0 0.5rem; }
.muted { color: var(--muted); }

/* Cards & stats */
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 1rem; margin: 1rem 0; }
.stat {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.1rem;
  text-align: center;
  box-shadow: 0 1px 2px rgba(0,0,0,0.04);
}
.stat .num { font-size: 1.9rem; font-weight: 700; color: var(--primary); }
.stat .label { color: var(--muted); font-size: 0.9rem; }

.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 0.8rem; }
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem;
  text-decoration: none;
  color: var(--text);
  transition: transform 0.08s, box-shadow 0.08s;
}
.card:hover { transform: translateY(-2px); box-shadow: 0 6px 14px rgba(0,0,0,0.08); }
.card strong { display: block; margin-bottom: 0.25rem; color: var(--primary-dark); }
.card span { font-size: 0.85rem; color: var(--muted); }

/* Cards / panels */
.panel {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.25rem;
  margin: 1rem 0;
  box-shadow: 0 1px 2px rgba(0,0,0,0.04);
}

/* Forms */
label { display: block; font-size: 0.9rem; font-weight: 600; margin: 0.6rem 0 0.2rem; }
input, select, textarea {
  width: 100%;
  padding: 0.55rem 0.7rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.95rem;
  font-family: inherit;
  background: #fff;
  color: var(--text);
}
input:focus, select:focus, textarea:focus { outline: 2px solid var(--primary); border-color: transparent; }
textarea { min-height: 90px; resize: vertical; }
.form-row { display: flex; gap: 0.75rem; flex-wrap: wrap; align-items: flex-end; }
.form-row > div { flex: 1; min-width: 140px; }

button, .btn {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 0.55rem 1rem;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  margin-top: 0.75rem;
}
button:hover, .btn:hover { background: var(--primary-dark); }
button.secondary, .btn.secondary { background: #fff; color: var(--primary); border: 1px solid var(--primary); }
button.secondary:hover, .btn.secondary:hover { background: #eef2ff; }
button.danger, .btn.danger { background: #fff; color: var(--error); border: 1px solid var(--error); }
button.danger:hover { background: #fef2f2; }
.btn.small { padding: 0.3rem 0.6rem; font-size: 0.85rem; margin: 0 0.2rem; }

/* Tables */
table { width: 100%; border-collapse: collapse; background: #fff; border-radius: 8px; overflow: hidden; margin: 0.5rem 0 1rem; }
th, td { text-align: left; padding: 0.6rem 0.75rem; border-bottom: 1px solid var(--border); font-size: 0.93rem; }
th { background: #f9fafb; color: var(--muted); font-weight: 600; }
tr:last-child td { border-bottom: none; }

/* Flash */
.flash { padding: 0.7rem 1rem; border-radius: 8px; margin: 0.75rem 0; font-size: 0.95rem; }
.flash-success { background: #ecfdf5; color: var(--success); border: 1px solid #a7f3d0; }
.flash-error { background: #fef2f2; color: var(--error); border: 1px solid #fecaca; }

/* Content output (lesson plan, summary) */
.pre { white-space: pre-wrap; background: #fafafa; border: 1px solid var(--border); border-radius: 8px; padding: 1rem; }

/* Auth */
.auth-card { max-width: 400px; margin: 4rem auto; }
.auth-card a { color: var(--primary); }

/* Grid helpers */
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
@media (max-width: 760px) { .grid2 { grid-template-columns: 1fr; } }

/* Documents preview */
.preview-frame { width: 100%; height: 520px; border: 1px solid var(--border); border-radius: 8px; }
.preview-img { max-width: 100%; border: 1px solid var(--border); border-radius: 8px; }

/* Signature pad */
.signature-canvas {
  border: 2px dashed var(--border);
  border-radius: 8px;
  background: #fbfbfd;
  width: 100%;
  height: 200px;
  touch-action: none;
  cursor: crosshair;
}
.signature-thumb { height: 90px; border: 1px solid var(--border); border-radius: 6px; background: #fff; }

/* Docs list */
.doc-row { display: flex; justify-content: space-between; align-items: center; gap: 1rem; padding: 0.7rem 0; border-bottom: 1px solid var(--border); }
.doc-row:last-child { border-bottom: none; }
.doc-name { font-weight: 600; }
.doc-meta { color: var(--muted); font-size: 0.85rem; }
.folder-chip { display: inline-block; background: #eef2ff; color: var(--primary-dark); padding: 0.2rem 0.55rem; border-radius: 999px; font-size: 0.8rem; margin: 0 0.25rem 0.25rem 0; text-decoration: none; }
.folder-chip:hover { background: #e0e7ff; }

/* Utility */
.inline-form { display: inline; }
.mt { margin-top: 0.75rem; }
.right { float: right; }

/* Language toggle options */
.nav-right a.lang-opt { color: #e0e2ff; text-decoration: none; font-size: 0.9rem; padding: 0.2rem 0.45rem; border-radius: 6px; }
.nav-right a.lang-opt.on { background: rgba(255,255,255,0.22); color: #fff; font-weight: 700; }

/* Quiz options */
.opts { margin: 0.35rem 0 0.35rem 1rem; }
.opts div { font-size: 0.95rem; }
.qz-section { font-size: 1rem; font-weight: 700; color: var(--primary-dark); margin: 1rem 0 0.4rem; }

/* Print: hide nav/buttons, keep the paper clean */
@media print {
  .navbar, button, .btn, .no-print { display: none !important; }
  body { background: #fff; }
  .container { max-width: 100%; margin: 0; padding: 0; }
  .panel { box-shadow: none; border: 1px solid #ccc; break-inside: avoid; }
}

/* Branding */
.logo { height: 40px; width: auto; vertical-align: middle; margin-right: 0.55rem; }
.brand { display: flex; align-items: center; }
.auth-logo { text-align: center; margin-bottom: 0.75rem; }
.auth-logo img { width: 100px; height: 100px; }

/* Chat widget */
.chat-toggle {
  position: fixed; bottom: 20px; right: 20px; width: 56px; height: 56px;
  border-radius: 50%; background: var(--primary); color: #fff;
  border: none; cursor: pointer; box-shadow: 0 4px 14px rgba(0,0,0,0.28); z-index: 9999; margin: 0;
  display: flex; align-items: center; justify-content: center; padding: 0;
}
.chat-panel {
  position: fixed; bottom: 88px; right: 20px; width: 340px; max-width: 92vw;
  background: #fff; border-radius: 14px; box-shadow: 0 10px 34px rgba(0,0,0,0.24);
  z-index: 9999; display: flex; flex-direction: column; overflow: hidden;
}
.chat-panel.hidden { display: none; }
.chat-header {
  background: var(--primary); color: #fff; padding: 0.7rem 1rem; font-weight: 700;
  display: flex; justify-content: space-between; align-items: center;
}
.chat-close { background: none; border: none; color: #fff; font-size: 1.4rem; cursor: pointer; margin: 0; padding: 0; }
.chat-messages {
  height: 300px; overflow-y: auto; padding: 0.75rem;
  display: flex; flex-direction: column; gap: 0.5rem; background: #f6f7fb;
}
.chat-msg { max-width: 85%; padding: 0.5rem 0.75rem; border-radius: 12px; font-size: 0.9rem; line-height: 1.4; white-space: pre-wrap; }
.chat-msg.user { align-self: flex-end; background: var(--primary); color: #fff; border-bottom-right-radius: 4px; }
.chat-msg.bot { align-self: flex-start; background: #fff; border: 1px solid var(--border); border-bottom-left-radius: 4px; display: flex; align-items: flex-start; gap: 0.4rem; }
.chat-input { display: flex; padding: 0.5rem; gap: 0.4rem; border-top: 1px solid var(--border); }
.chat-input input { flex: 1; margin: 0; }
.chat-input button { margin: 0; white-space: nowrap; }
.robot-icon { width: 30px; height: 30px; }
.robot-avatar { width: 26px; height: 26px; flex-shrink: 0; }
.chat-header-title { display: flex; align-items: center; gap: 0.5rem; }
.chat-bot-avatar { width: 18px; height: 18px; flex-shrink: 0; margin-top: 1px; }
.chat-attach { margin: 0; background: #fff; color: var(--primary); border: 1px solid var(--border); border-radius: 8px; padding: 0 0.6rem; font-size: 1rem; cursor: pointer; }
.chat-attach:hover { background: #eef2ff; }
.chat-link { display: block; margin-top: 6px; color: var(--primary); font-weight: 600; }
.chat-bot-body { display: flex; flex-direction: column; }

/* Tabs (Document Studio) */
.tabs { display: flex; gap: 0.5rem; margin: 1rem 0; flex-wrap: wrap; }
.tab { background: #fff; border: 1px solid var(--border); padding: 0.5rem 1rem; border-radius: 8px; cursor: pointer; font-weight: 600; margin: 0; color: var(--text); }
.tab.active { background: var(--primary); color: #fff; border-color: var(--primary); }
.tab-panel { margin-top: 0; }

/* Study Studio */
.study-layout { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 1rem; align-items: start; }
.study-col { background: #fff; border: 1px solid var(--border); border-radius: 12px; padding: 1rem; min-height: 420px; }
.study-col h2, .study-col h3 { margin-top: 0; }
.nb-list, .src-list { list-style: none; padding: 0; margin: 0.5rem 0; }
.nb-item { display: flex; justify-content: space-between; align-items: center; padding: 0.5rem; border-radius: 8px; cursor: pointer; border: 1px solid transparent; }
.nb-item.active { background: #eef2ff; border-color: var(--primary); }
.nb-name { flex: 1; font-weight: 600; }
.src-list li { display: flex; justify-content: space-between; align-items: center; padding: 0.3rem 0; border-bottom: 1px dashed var(--border); font-size: 0.9rem; }
.chat-log { height: 320px; overflow-y: auto; border: 1px solid var(--border); border-radius: 8px; padding: 0.5rem; background: #fafafa; margin-bottom: 0.5rem; }
.msg { margin: 0.4rem 0; padding: 0.5rem 0.7rem; border-radius: 10px; max-width: 90%; white-space: pre-wrap; }
.msg.user { background: var(--primary); color: #fff; margin-left: auto; }
.msg.bot { background: #eef2ff; }
.msg.note { background: #fff7ed; color: #9a5b00; font-size: 0.85rem; }
.chat-input { display: flex; gap: 0.4rem; align-items: flex-end; }
.chat-input textarea { flex: 1; }
.cites { margin-top: 0.3rem; }
.cite { background: #fff; border-left: 3px solid var(--primary); padding: 0.4rem 0.6rem; font-size: 0.8rem; margin: 0.3rem 0; border-radius: 0 6px 6px 0; }
.gen-row { display: flex; gap: 0.4rem; margin-bottom: 0.5rem; flex-wrap: wrap; }
.gen-row select, .gen-row input { flex: 1; min-width: 90px; }
.out-card { border: 1px solid var(--border); border-radius: 10px; padding: 0.8rem; margin-top: 0.8rem; }
.out-card h3 { margin-top: 0; }
.links { display: flex; gap: 0.4rem; flex-wrap: wrap; margin: 0.5rem 0; }
.quiz-list li { margin-bottom: 0.7rem; }
.ans { color: #15803d; font-size: 0.85rem; }
.items-list .item-row { display: flex; gap: 0.4rem; align-items: center; padding: 0.3rem 0; border-bottom: 1px dashed var(--border); font-size: 0.85rem; flex-wrap: wrap; }
.svg-wrap svg { width: 100%; height: auto; border: 1px solid var(--border); border-radius: 10px; margin-top: 0.5rem; }

/* Flashcards */
.cards-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 1rem; }
.flashcard { perspective: 1000px; height: 180px; cursor: pointer; }
.fc-inner { position: relative; width: 100%; height: 100%; transition: transform 0.5s; transform-style: preserve-3d; }
.flashcard.flipped .fc-inner { transform: rotateY(180deg); }
.fc-face { position: absolute; width: 100%; height: 100%; backface-visibility: hidden; display: flex; align-items: center; justify-content: center; padding: 1rem; border-radius: 12px; text-align: center; font-size: 0.95rem; box-sizing: border-box; }
.fc-front { background: var(--primary); color: #fff; font-weight: 600; }
.fc-back { background: #fff; color: var(--text); transform: rotateY(180deg); border: 1px solid var(--border); overflow-y: auto; }

@media (max-width: 900px) {
  .study-layout { grid-template-columns: 1fr; }
}