/* ═══════════════════════════════════════════
   STREAM AI · School Intelligence OS
   Premium Design System v2
   ═══════════════════════════════════════════ */

:root {
  --primary: #2563eb;
  --primary-light: #3b82f6;
  --primary-dark: #1d4ed8;
  --primary-deeper: #1e3a5f;
  --accent: #0891b2;
  --accent2: #7c3aed;
  --success: #10b981;
  --danger: #ef4444;
  --warning: #f59e0b;
  --bg: #f3f6fb;
  --bg-card: rgba(255, 255, 255, 0.94);
  --bg-card-solid: #ffffff;
  --bg-surface: #f8fafc;
  --sidebar-bg: rgba(255, 255, 255, 0.96);
  --sidebar-hover: rgba(226, 232, 240, 0.75);
  --text: #334155;
  --text-secondary: #64748b;
  --text-bright: #0f172a;
  --border: rgba(148, 163, 184, 0.3);
  --glass: rgba(255, 255, 255, 0.84);
  --glow-blue: rgba(37, 99, 235, 0.1);
  --glow-cyan: rgba(8, 145, 178, 0.1);
  --shadow-sm: 0 8px 20px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 16px 36px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 24px 60px rgba(15, 23, 42, 0.12);
  --shadow-glow: 0 10px 28px rgba(37,99,235,0.12);
  --radius: 12px;
  --radius-lg: 16px;
  --sidebar-width: 250px;
  --topbar-height: 60px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

* { margin:0; padding:0; box-sizing:border-box; }

body {
  font-family: 'Noto Sans TC', 'Inter', -apple-system, sans-serif;
  background: linear-gradient(180deg, #f8fbff 0%, #eef3f9 48%, #f3f6fb 100%);
  color: var(--text);
  line-height: 1.6;
  overflow: hidden;
  height: 100vh;
}

.hidden { display: none !important; }

/* ─── Splash ─── */
#splash {
  position: fixed; inset: 0;
  background: radial-gradient(circle at top, rgba(59,130,246,0.12), transparent 35%), linear-gradient(180deg, #ffffff 0%, #eef3f9 100%);
  display: flex; align-items: center; justify-content: center;
  z-index: 9999;
  transition: opacity 0.8s ease, visibility 0.8s ease;
}
#splash.fade-out { opacity: 0; visibility: hidden; }
#splashCanvas { position: absolute; inset: 0; z-index: 0; }
.splash-inner { position: relative; z-index: 1; text-align: center; }
.splash-logo-ring {
  width: 80px; height: 80px; margin: 0 auto 20px;
  border-radius: 20px; display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  box-shadow: 0 18px 40px rgba(37,99,235,0.18), 0 0 0 10px rgba(255,255,255,0.75);
  animation: logoFloat 3s ease-in-out infinite;
}
.splash-logo-text { font-size: 1.42rem; font-weight: 800; letter-spacing: 0.12em; color: white; }
.splash-title {
  font-size: 2.8rem; font-weight: 800; letter-spacing: -0.03em;
  background: linear-gradient(135deg, #2563eb, #0891b2, #7c3aed);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.splash-sub { color: #64748b; font-size: 0.95rem; margin-top: 6px; }
.splash-bar { width: 220px; height: 3px; background: rgba(148,163,184,0.3); border-radius: 3px; margin: 24px auto 12px; overflow: hidden; }
.splash-bar-fill { width: 0; height: 100%; background: linear-gradient(90deg, var(--primary), var(--accent)); border-radius: 3px; animation: loadBar 2s ease-in-out forwards; }
.splash-status { color: #94a3b8; font-size: 0.75rem; }
@keyframes loadBar { to { width: 100%; } }
@keyframes logoFloat { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-6px); } }

/* ─── App Layout ─── */
.app { display: flex; height: 100vh; overflow: hidden; background: var(--bg); }

/* ─── Auth Gate ─── */
.auth-gate {
  position: fixed; inset: 0; z-index: 9000;
  background:
    radial-gradient(circle at top right, rgba(37,99,235,0.12), transparent 28%),
    radial-gradient(circle at bottom left, rgba(124,58,237,0.12), transparent 26%),
    linear-gradient(180deg, #f8fbff 0%, #eef3f9 100%);
  display: flex; align-items: center; justify-content: center;
  padding: 28px;
}
.auth-shell {
  width: min(980px, 100%);
  display: grid; grid-template-columns: 1.1fr 0.9fr;
  gap: 22px;
}
.auth-hero,
.auth-panel {
  background: rgba(255,255,255,0.92);
  border: 1px solid var(--border);
  border-radius: 24px;
  box-shadow: var(--shadow-lg);
  padding: 30px;
  backdrop-filter: blur(18px);
}
.auth-hero {
  display: flex; flex-direction: column; justify-content: space-between;
  min-height: 520px;
}
.auth-logo-box {
  width: 78px; height: 78px; border-radius: 24px;
  background: #fff; box-shadow: 0 14px 36px rgba(37,99,235,0.16);
  display: flex; align-items: center; justify-content: center;
  padding: 10px; margin-bottom: 18px;
}
.auth-logo-box img {
  width: 100%; height: 100%; object-fit: contain; border-radius: 18px;
}
.auth-kicker {
  font-size: 0.78rem; font-weight: 700; letter-spacing: 0.18em;
  color: var(--primary); text-transform: uppercase; margin-bottom: 10px;
}
.auth-title {
  font-size: 2.2rem; line-height: 1.15; color: var(--text-bright);
  font-weight: 800; letter-spacing: -0.03em;
}
.auth-subtitle {
  margin-top: 12px; color: var(--text-secondary); font-size: 0.92rem;
}
.auth-bullets {
  display: grid; gap: 10px; margin-top: 22px;
}
.auth-bullet {
  background: var(--bg-surface); border: 1px solid var(--border);
  border-radius: 14px; padding: 12px 14px; font-size: 0.84rem; color: var(--text);
}
.auth-bullet strong { color: var(--text-bright); }
.auth-link-note {
  margin-top: 18px; font-size: 0.8rem; color: var(--text-secondary);
}
.auth-panel-title {
  font-size: 1.15rem; font-weight: 700; color: var(--text-bright); margin-bottom: 8px;
}
.auth-panel-subtitle {
  font-size: 0.82rem; color: var(--text-secondary); margin-bottom: 20px;
}
.auth-form .form-group { margin-bottom: 14px; }
.auth-error {
  margin-top: 10px; border-radius: 12px; padding: 10px 12px;
  font-size: 0.8rem; background: rgba(239,68,68,0.1); color: #b91c1c;
  border: 1px solid rgba(239,68,68,0.18);
}
.auth-demo-grid {
  display: grid; gap: 8px; margin-top: 18px;
}
.auth-demo-btn {
  text-align: left; border: 1px solid var(--border); background: #fff;
  border-radius: 14px; padding: 12px 14px; cursor: pointer;
  transition: all var(--transition); box-shadow: var(--shadow-sm);
}
.auth-demo-btn:hover {
  border-color: rgba(37,99,235,0.28);
  box-shadow: var(--shadow-glow);
  transform: translateY(-1px);
}
.auth-demo-btn strong {
  display: block; color: var(--text-bright); font-size: 0.84rem;
}
.auth-demo-btn span {
  display: block; font-size: 0.76rem; color: var(--text-secondary); margin-top: 2px;
}

/* ─── Sidebar ─── */
.sidebar {
  width: var(--sidebar-width); background: var(--sidebar-bg);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  display: flex; flex-direction: column;
  position: fixed; top: 0; left: 0; bottom: 0; z-index: 100;
  border-right: 1px solid var(--border);
  box-shadow: 12px 0 40px rgba(15,23,42,0.04);
  transition: transform var(--transition);
}
.sidebar-header { display: flex; align-items: center; gap: 12px; padding: 18px 18px 14px; }
.logo-mark {
  width: 42px; height: 42px; border-radius: 12px;
  background: #ffffff;
  display: flex; align-items: center; justify-content: center;
  box-shadow: 0 10px 22px rgba(37,99,235,0.18);
  padding: 4px;
  overflow: hidden;
}
.logo-mark span { font-size: 0.72rem; font-weight: 800; color: white; letter-spacing: 0.12em; }
.logo-mark img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
  border-radius: 10px;
}
.logo-title { display: block; font-weight: 700; font-size: 1rem; color: var(--text-bright); letter-spacing: -0.02em; }
.logo-sub { display: block; font-size: 0.65rem; color: var(--text-secondary); }
.sidebar-section-label {
  padding: 12px 20px 4px; font-size: 0.65rem; font-weight: 600;
  color: var(--text-secondary); text-transform: uppercase; letter-spacing: 1.5px;
}
.sidebar-nav { padding: 2px 8px; }
.nav-item {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 12px; border-radius: 10px;
  color: var(--text-secondary); text-decoration: none;
  font-size: 0.85rem; font-weight: 500;
  transition: all var(--transition); margin-bottom: 1px;
}
.nav-item:hover { background: var(--sidebar-hover); color: var(--text); }
.nav-item.active {
  background: linear-gradient(135deg, rgba(37,99,235,0.12), rgba(8,145,178,0.08));
  color: var(--text-bright); border: 1px solid rgba(37,99,235,0.3);
  box-shadow: var(--shadow-glow);
}
.nav-icon { width: 20px; height: 20px; display: flex; align-items: center; justify-content: center; flex-shrink: 0; }
.nav-icon svg { width: 18px; height: 18px; }
.sidebar-footer { margin-top: auto; padding: 14px 14px; border-top: 1px solid var(--border); }
.sidebar-user { display: flex; align-items: center; gap: 10px; }
.sidebar-logout { margin-top: 12px; width: 100%; justify-content: center; }
.user-avatar {
  width: 34px; height: 34px; border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--accent2));
  display: flex; align-items: center; justify-content: center;
  color: white; font-weight: 700; font-size: 0.8rem;
}
.user-name { color: var(--text); font-size: 0.82rem; font-weight: 600; }
.user-role { color: var(--text-secondary); font-size: 0.68rem; }

/* ─── Main ─── */
.main-content { margin-left: var(--sidebar-width); flex: 1; display: flex; flex-direction: column; height: 100vh; overflow: hidden; }

/* ─── Topbar ─── */
.topbar {
  height: var(--topbar-height); background: rgba(255,255,255,0.88);
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 8px 24px rgba(15,23,42,0.04);
  display: flex; align-items: center; gap: 16px; padding: 0 24px; flex-shrink: 0;
}
.menu-toggle { display: none; background: none; border: none; font-size: 1.3rem; cursor: pointer; color: var(--text); }
.topbar-left { flex: 1; }
.breadcrumb { font-size: 1rem; font-weight: 600; color: var(--text-bright); }
.topbar-right { display: flex; align-items: center; gap: 14px; }
.search-input {
  padding: 7px 14px; border: 1px solid var(--border); background: var(--bg-surface);
  border-radius: 8px; font-size: 0.82rem; width: 180px; color: var(--text);
  outline: none; transition: border var(--transition);
}
.search-input:focus { border-color: var(--primary); box-shadow: 0 0 0 2px rgba(37,99,235,0.2); }
.search-input::placeholder { color: var(--text-secondary); }
.topbar-badge { position: relative; cursor: pointer; font-size: 1rem; }
.notif-count {
  position: absolute; top: -6px; right: -10px;
  background: var(--danger); color: white; font-size: 0.6rem;
  width: 16px; height: 16px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center; font-weight: 700;
}
.view-toggle { display: flex; gap: 3px; background: var(--bg-surface); padding: 3px; border-radius: 8px; border: 1px solid var(--border); }
.view-btn {
  padding: 5px 10px; border: none; background: transparent; border-radius: 6px;
  cursor: pointer; font-size: 0.75rem; font-weight: 500;
  transition: all var(--transition); white-space: nowrap; color: var(--text-secondary);
}
.view-btn.active { background: var(--primary); color: white; box-shadow: 0 0 12px rgba(37,99,235,0.3); }

/* ─── Page Container ─── */
.page-container { flex: 1; overflow-y: auto; padding: 24px; scroll-behavior: smooth; }

/* ─── Common ─── */
.page { animation: fadeIn 0.35s ease-out; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }

.page-header { margin-bottom: 24px; }
.page-title { font-size: 1.5rem; font-weight: 700; color: var(--text-bright); display: flex; align-items: center; gap: 10px; }
.page-title-badge {
  font-size: 0.65rem; font-weight: 600; padding: 3px 10px;
  border-radius: 20px; background: linear-gradient(135deg, var(--primary), var(--accent));
  color: white; letter-spacing: 0.5px;
}
.page-desc { color: var(--text-secondary); font-size: 0.85rem; margin-top: 4px; display: flex; align-items: center; gap: 8px; }

/* KPI Cards */
.kpi-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; margin-bottom: 24px; }
.kpi-card {
  background: var(--bg-card); backdrop-filter: blur(10px);
  border-radius: var(--radius); padding: 18px; border: 1px solid var(--border);
  box-shadow: var(--shadow-sm); transition: all var(--transition);
  position: relative; overflow: hidden;
}
.kpi-card:hover { border-color: rgba(37,99,235,0.28); box-shadow: var(--shadow-glow); transform: translateY(-2px); }
.kpi-card::after {
  content: ''; position: absolute; top: 0; right: 0;
  width: 80px; height: 80px; border-radius: 50%;
  opacity: 0.05; filter: blur(20px);
}
.kpi-card.blue::after { background: var(--primary); }
.kpi-card.green::after { background: var(--success); }
.kpi-card.cyan::after { background: var(--accent); }
.kpi-card.amber::after { background: var(--warning); }
.kpi-card.purple::after { background: var(--accent2); }
.kpi-icon { font-size: 1.3rem; margin-bottom: 8px; width: 36px; height: 36px; border-radius: 10px; display: flex; align-items: center; justify-content: center; }
.kpi-card.blue .kpi-icon { background: rgba(37,99,235,0.15); }
.kpi-card.green .kpi-icon { background: rgba(16,185,129,0.15); }
.kpi-card.cyan .kpi-icon { background: rgba(6,182,212,0.15); }
.kpi-card.amber .kpi-icon { background: rgba(245,158,11,0.15); }
.kpi-card.purple .kpi-icon { background: rgba(139,92,246,0.15); }
.kpi-label { font-size: 0.75rem; color: var(--text-secondary); font-weight: 500; }
.kpi-value { font-size: 1.8rem; font-weight: 700; color: var(--text-bright); margin: 4px 0; letter-spacing: -0.02em; }
.kpi-change { font-size: 0.72rem; font-weight: 600; }
.kpi-change.up { color: var(--success); }
.kpi-change.down { color: var(--danger); }

/* Grid */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-bottom: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin-bottom: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; margin-bottom: 24px; }
.grid-5 { display: grid; grid-template-columns: repeat(5, 1fr); gap: 16px; margin-bottom: 24px; }

/* Card */
.card {
  background: var(--bg-card); backdrop-filter: blur(10px);
  border-radius: var(--radius-lg); padding: 22px; border: 1px solid var(--border);
  box-shadow: var(--shadow-sm); transition: all var(--transition);
}
.card:hover { border-color: rgba(71,85,105,0.6); }
.card-title { font-size: 0.9rem; font-weight: 600; color: var(--text-bright); margin-bottom: 14px; display: flex; align-items: center; gap: 8px; }
.card-title .icon { font-size: 1rem; opacity: 0.8; }

.chart-container { position: relative; height: 260px; }
.chart-container-sm { position: relative; height: 200px; }

/* Badges */
.badge { display: inline-block; padding: 2px 9px; border-radius: 20px; font-size: 0.7rem; font-weight: 600; }
.badge-blue { background: rgba(37,99,235,0.12); color: #2563eb; }
.badge-green { background: rgba(16,185,129,0.12); color: #059669; }
.badge-amber { background: rgba(245,158,11,0.14); color: #b45309; }
.badge-red { background: rgba(239,68,68,0.12); color: #dc2626; }
.badge-cyan { background: rgba(8,145,178,0.12); color: #0f766e; }
.badge-purple { background: rgba(124,58,237,0.12); color: #7c3aed; }

/* Progress */
.progress-bar { width: 100%; height: 6px; background: rgba(71,85,105,0.3); border-radius: 6px; overflow: hidden; margin: 6px 0; }
.progress-fill { height: 100%; border-radius: 6px; transition: width 1s ease-out; background: linear-gradient(90deg, var(--primary), var(--accent)); }

/* Table */
.table-wrapper { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 0.82rem; }
th { text-align: left; padding: 10px 12px; font-weight: 600; color: var(--text-secondary); border-bottom: 1px solid var(--border); font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.5px; }
td { padding: 10px 12px; border-bottom: 1px solid rgba(148,163,184,0.22); color: var(--text); }
tr:hover td { background: rgba(226,232,240,0.45); }

.pill-tag { display: inline-block; padding: 2px 8px; margin: 1px; border-radius: 6px; font-size: 0.72rem; font-weight: 600; background: rgba(37,99,235,0.1); color: #2563eb; }

.section-title {
  font-size: 1.05rem; font-weight: 600; color: var(--text-bright);
  margin: 4px 0 16px; padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 8px;
}

/* Buttons */
.btn {
  padding: 8px 16px; border: none; border-radius: 8px;
  font-size: 0.82rem; font-weight: 600; cursor: pointer;
  transition: all var(--transition); display: inline-flex; align-items: center; gap: 6px;
}
.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover { background: var(--primary-light); box-shadow: 0 0 16px rgba(37,99,235,0.3); }
.btn-outline { background: transparent; color: var(--primary-light); border: 1px solid var(--primary); }
.btn-outline:hover { background: var(--primary); color: white; }
.btn-success { background: var(--success); color: white; }
.btn-sm { padding: 5px 12px; font-size: 0.75rem; }
.btn-ghost { background: transparent; color: var(--text-secondary); border: 1px solid var(--border); }
.btn-ghost:hover { background: var(--bg-surface); color: var(--text); }

/* Tabs */
.tab-bar { display: flex; gap: 3px; margin-bottom: 20px; background: var(--bg-surface); padding: 3px; border-radius: 10px; border: 1px solid var(--border); flex-wrap: wrap; }
.tab-item {
  padding: 8px 14px; border-radius: 8px; border: none; background: transparent;
  cursor: pointer; font-size: 0.82rem; font-weight: 500;
  transition: all var(--transition); color: var(--text-secondary); white-space: nowrap;
}
.tab-item.active { background: var(--primary); color: white; box-shadow: 0 0 12px rgba(37,99,235,0.2); }

/* Agent Flow */
.agent-flow { display: flex; align-items: center; justify-content: center; gap: 10px; flex-wrap: wrap; margin: 20px 0; }
.agent-node {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 18px; text-align: center; min-width: 140px;
  transition: all var(--transition); cursor: pointer;
}
.agent-node:hover { border-color: var(--primary); box-shadow: var(--shadow-glow); transform: translateY(-3px); }
.agent-node.active { border-color: var(--primary); background: rgba(37,99,235,0.08); box-shadow: var(--shadow-glow); }
.agent-node .agent-emoji { font-size: 1.8rem; margin-bottom: 6px; }
.agent-node .agent-name { font-weight: 600; font-size: 0.82rem; color: var(--text-bright); }
.agent-node .agent-sub { font-size: 0.7rem; color: var(--text-secondary); }
.agent-arrow { font-size: 1.3rem; color: var(--primary-light); }

/* Metrics */
.metric-row { display: flex; justify-content: space-between; align-items: center; padding: 8px 0; border-bottom: 1px solid rgba(148,163,184,0.18); }
.metric-row:last-child { border-bottom: none; }
.metric-label { font-size: 0.82rem; color: var(--text-secondary); }
.metric-val { font-size: 0.85rem; font-weight: 600; color: var(--text-bright); }

/* Status */
.status-dot { width: 7px; height: 7px; border-radius: 50%; display: inline-block; margin-right: 6px; }
.status-dot.green { background: var(--success); box-shadow: 0 0 6px rgba(16,185,129,0.5); }
.status-dot.amber { background: var(--warning); }
.status-dot.red { background: var(--danger); }
.status-dot.blue { background: var(--primary); }

/* Live dot */
.live-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--success); display: inline-block; animation: livePulse 2s infinite; }
@keyframes livePulse { 0%,100% { box-shadow: 0 0 0 0 rgba(16,185,129,0.4); } 50% { box-shadow: 0 0 0 5px rgba(16,185,129,0); } }

/* AI Processing */
.ai-dots { display: flex; gap: 4px; align-items: center; }
.ai-dots .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--primary-light); animation: aiDots 1.4s infinite ease-in-out both; }
.ai-dots .dot:nth-child(2) { animation-delay: 0.16s; }
.ai-dots .dot:nth-child(3) { animation-delay: 0.32s; }
@keyframes aiDots { 0%,80%,100% { transform: scale(0); } 40% { transform: scale(1); } }

/* Heatmap */
.heatmap-grid { display: grid; grid-template-columns: repeat(6, 1fr); gap: 4px; }
.heat-cell {
  aspect-ratio: 1; border-radius: 6px; display: flex; align-items: center; justify-content: center;
  font-size: 0.68rem; font-weight: 600; transition: transform var(--transition);
}
.heat-cell:hover { transform: scale(1.12); }

/* Timeline */
.timeline { position: relative; padding-left: 28px; }
.timeline::before { content: ''; position: absolute; left: 9px; top: 0; bottom: 0; width: 2px; background: var(--border); }
.timeline-item { position: relative; margin-bottom: 18px; }
.timeline-item::before {
  content: ''; position: absolute; left: -23px; top: 4px;
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--primary); border: 2px solid var(--bg);
  box-shadow: 0 0 0 2px var(--primary);
}
.timeline-item.completed::before { background: var(--success); box-shadow: 0 0 0 2px var(--success); }
.timeline-title { font-weight: 600; font-size: 0.88rem; color: var(--text-bright); }
.timeline-desc { font-size: 0.8rem; color: var(--text-secondary); }

/* Lab cards */
.lab-card {
  background: var(--bg-card); border-radius: var(--radius-lg); padding: 22px;
  border: 1px solid var(--border); transition: all var(--transition); cursor: pointer;
  position: relative; overflow: hidden;
}
.lab-card:hover { border-color: rgba(37,99,235,0.4); box-shadow: var(--shadow-glow); transform: translateY(-3px); }
.lab-card .lab-emoji { font-size: 2.2rem; margin-bottom: 8px; }
.lab-card .lab-title { font-size: 0.95rem; font-weight: 600; color: var(--text-bright); margin-bottom: 4px; }
.lab-card .lab-desc { font-size: 0.78rem; color: var(--text-secondary); }

/* HITL */
.hitl-flow { display: flex; gap: 12px; align-items: stretch; margin: 16px 0; }
.hitl-step {
  flex: 1; background: var(--bg-surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 16px; text-align: center;
  transition: all var(--transition);
}
.hitl-step.active { border-color: var(--primary); box-shadow: var(--shadow-glow); }
.hitl-step.done { border-color: var(--success); }
.hitl-step-num { font-size: 0.7rem; font-weight: 600; color: var(--text-secondary); margin-bottom: 6px; }
.hitl-step-icon { font-size: 1.6rem; margin-bottom: 6px; }
.hitl-step-title { font-weight: 600; font-size: 0.82rem; color: var(--text-bright); }
.hitl-step-desc { font-size: 0.72rem; color: var(--text-secondary); margin-top: 4px; }
.hitl-arrow { display: flex; align-items: center; color: var(--primary-light); font-size: 1.2rem; }

/* Model selector */
.model-selector { display: flex; gap: 4px; padding: 3px; background: var(--bg-surface); border-radius: 8px; border: 1px solid var(--border); }
.model-btn {
  padding: 5px 12px; border: none; background: transparent; border-radius: 6px;
  cursor: pointer; font-size: 0.75rem; font-weight: 500; color: var(--text-secondary);
  transition: all var(--transition);
}
.model-btn.active { background: var(--primary); color: white; }

/* Toast */
.toast-container { position: fixed; top: 20px; right: 20px; z-index: 10000; display: flex; flex-direction: column; gap: 8px; }
.toast {
  background: rgba(255,255,255,0.98); color: var(--text); padding: 12px 20px;
  border-radius: 10px; font-size: 0.82rem; box-shadow: var(--shadow-lg);
  animation: slideIn 0.3s ease-out; border: 1px solid var(--border);
  display: flex; align-items: center; gap: 8px;
}
.toast.success { border-left: 3px solid var(--success); }
.toast.info { border-left: 3px solid var(--accent); }
@keyframes slideIn { from { transform: translateX(100%); opacity: 0; } }

/* Modal */
.modal-overlay {
  position: fixed; inset: 0; background: rgba(15,23,42,0.24);
  z-index: 9000; display: none; align-items: center; justify-content: center;
  backdrop-filter: blur(6px);
}
.modal-overlay.open { display: flex; }
.modal {
  background: var(--bg-card-solid); border: 1px solid var(--border);
  border-radius: var(--radius-lg); max-width: 750px; width: 92%;
  max-height: 85vh; overflow-y: auto; padding: 28px; position: relative;
  animation: modalIn 0.3s ease-out; box-shadow: var(--shadow-lg);
}
@keyframes modalIn { from { transform: scale(0.95); opacity: 0; } }
@keyframes spin { to { transform: rotate(360deg); } }
.modal-close { position: absolute; top: 12px; right: 16px; background: none; border: none; font-size: 1.5rem; cursor: pointer; color: var(--text-secondary); }

/* Demo content blocks */
.demo-block {
  background: rgba(37,99,235,0.05); border: 1px solid rgba(37,99,235,0.12);
  border-radius: var(--radius); padding: 16px; margin: 10px 0;
}
.demo-block.green { background: rgba(16,185,129,0.06); border-color: rgba(16,185,129,0.15); }
.demo-block.amber { background: rgba(245,158,11,0.06); border-color: rgba(245,158,11,0.15); }
.demo-block.purple { background: rgba(139,92,246,0.06); border-color: rgba(139,92,246,0.15); }
.demo-block-title { font-weight: 600; font-size: 0.88rem; color: var(--text-bright); margin-bottom: 6px; }

/* Form elements */
.form-group { margin-bottom: 12px; }
.form-label { font-size: 0.78rem; color: var(--text-secondary); display: block; margin-bottom: 4px; font-weight: 500; }
.form-input, .form-select, .form-textarea {
  width: 100%; padding: 8px 12px; border: 1px solid var(--border);
  background: var(--bg-surface); border-radius: 8px; font-size: 0.85rem;
  color: var(--text); outline: none; transition: border var(--transition);
  font-family: inherit;
}
.form-input:focus, .form-select:focus, .form-textarea:focus { border-color: var(--primary); box-shadow: 0 0 0 2px rgba(37,99,235,0.15); }
.form-textarea { resize: vertical; min-height: 70px; }
.form-select { cursor: pointer; }

/* Scrollbar */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: rgba(148,163,184,0.55); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: rgba(100,116,139,0.7); }

/* Responsive */
@media (max-width: 1200px) { .grid-4, .grid-5 { grid-template-columns: repeat(2, 1fr); } .auth-shell { grid-template-columns: 1fr; } .auth-hero { min-height: auto; } }
@media (max-width: 900px) {
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .sidebar { transform: translateX(-100%); }
  .sidebar.open { transform: translateX(0); }
  .main-content { margin-left: 0; }
  .menu-toggle { display: block; }
  .view-toggle, .topbar-search { display: none; }
  .hitl-flow { flex-direction: column; }
  .hitl-arrow { transform: rotate(90deg); justify-content: center; }
  .auth-gate { padding: 18px; }
  .auth-hero, .auth-panel { padding: 24px; border-radius: 18px; }
  .auth-title { font-size: 1.8rem; }
}
@media (max-width: 600px) { .kpi-grid { grid-template-columns: 1fr 1fr; } .grid-4, .grid-5 { grid-template-columns: 1fr; } .page-container { padding: 14px; } .auth-gate { padding: 14px; } .auth-hero, .auth-panel { padding: 20px; } }

/* Glow line */
.glow-line { height: 1px; background: linear-gradient(90deg, transparent, rgba(37,99,235,0.25), rgba(8,145,178,0.18), transparent); margin: 20px 0; opacity: 1; }

.brand-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: 999px;
  background: rgba(37,99,235,0.08);
  border: 1px solid rgba(37,99,235,0.12);
  color: var(--primary);
  font-size: 0.72rem;
  font-weight: 700;
}

.info-pills {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-top: 10px;
}

.info-pill {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 5px 10px;
  border-radius: 999px;
  background: rgba(226,232,240,0.75);
  color: var(--text-secondary);
  border: 1px solid rgba(148,163,184,0.22);
  font-size: 0.74rem;
  font-weight: 600;
}

.soft-panel {
  background: linear-gradient(180deg, rgba(255,255,255,0.92), rgba(248,250,252,0.88));
  border: 1px solid rgba(148,163,184,0.22);
  border-radius: 14px;
  box-shadow: var(--shadow-sm);
}

.muted-note {
  font-size: 0.78rem;
  color: var(--text-secondary);
}

/* Gauge ring */
.gauge-wrapper { text-align: center; padding: 12px; }
.gauge-ring {
  width: 110px; height: 110px; border-radius: 50%;
  border: 6px solid rgba(71,85,105,0.3); position: relative;
  margin: 0 auto 10px; display: flex; align-items: center; justify-content: center;
}
.gauge-value { font-size: 2rem; font-weight: 700; color: var(--text-bright); }
.gauge-label { font-size: 0.78rem; color: var(--text-secondary); }

/* Teaching center enhancements */
.field-action-row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.field-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 4px;
  flex-wrap: wrap;
}

.image-card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
  margin-top: 14px;
}

.image-card {
  background: linear-gradient(180deg, rgba(255,255,255,0.98), rgba(248,250,252,0.96));
  border: 1px solid rgba(148,163,184,0.22);
  border-radius: 18px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition);
}

.image-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
  border-color: rgba(37,99,235,0.28);
}

.image-card img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  display: block;
  background: #eef2ff;
}

.image-card-body {
  padding: 14px;
}

.image-card-title {
  font-size: 0.86rem;
  font-weight: 700;
  color: var(--text-bright);
  margin-bottom: 6px;
}

.image-card-prompt {
  font-size: 0.78rem;
  line-height: 1.65;
  color: var(--text-secondary);
}

.a4-preview-shell {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
}

.a4-preview-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 12px;
}

.a4-paper {
  width: min(100%, 820px);
  min-height: 980px;
  margin: 0 auto;
  padding: 30px;
  background: #ffffff;
  border-radius: 18px;
  border: 1px solid rgba(148,163,184,0.26);
  box-shadow: 0 22px 50px rgba(15,23,42,0.12);
}

.a4-paper-brand {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  padding-bottom: 18px;
  border-bottom: 1px solid #e2e8f0;
}

.a4-paper-brand-title {
  font-size: 1rem;
  font-weight: 800;
  color: #0f172a;
}

.a4-paper-brand-sub {
  margin-top: 4px;
  font-size: 0.8rem;
  color: #64748b;
}

.a4-paper-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(37,99,235,0.08);
  border: 1px solid rgba(37,99,235,0.15);
  color: #2563eb;
  font-size: 0.74rem;
  font-weight: 700;
  white-space: nowrap;
}

.a4-paper-main {
  padding: 22px 0 18px;
  color: #1e293b;
  font-size: 0.92rem;
  line-height: 1.8;
}

.a4-paper-main h1,
.a4-paper-main h2,
.a4-paper-main h3,
.a4-paper-main h4 {
  color: #0f172a;
  margin: 0 0 10px;
}

.a4-paper-main p {
  margin: 0 0 10px;
}

.a4-paper-main ul,
.a4-paper-main ol {
  margin: 0 0 14px;
  padding-left: 22px;
}

.a4-paper-main li + li {
  margin-top: 6px;
}

.a4-paper-footer {
  padding-top: 16px;
  border-top: 1px dashed #cbd5e1;
  color: #64748b;
  font-size: 0.76rem;
}

/* Marking and task controls */
.source-chip-group {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.source-chip {
  border: 1px solid rgba(148,163,184,0.28);
  background: #ffffff;
  color: var(--text-secondary);
  border-radius: 999px;
  padding: 8px 14px;
  font-size: 0.78rem;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--transition);
}

.source-chip:hover,
.source-chip.active {
  background: rgba(37,99,235,0.08);
  border-color: rgba(37,99,235,0.26);
  color: var(--primary);
  box-shadow: var(--shadow-sm);
}

.custom-task-card {
  background: linear-gradient(180deg, rgba(255,255,255,0.98), rgba(248,250,252,0.94));
  border: 1px solid rgba(148,163,184,0.22);
  border-radius: 14px;
  padding: 14px;
  box-shadow: var(--shadow-sm);
}

/* Sharing and class management */
.share-card {
  background: linear-gradient(180deg, rgba(255,255,255,0.98), rgba(248,250,252,0.95));
  border: 1px solid rgba(148,163,184,0.22);
  border-radius: 16px;
  padding: 18px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition);
  height: 100%;
}

.share-card:hover {
  transform: translateY(-2px);
  border-color: rgba(37,99,235,0.25);
  box-shadow: var(--shadow-glow);
}

.share-modal-grid {
  display: grid;
  grid-template-columns: minmax(220px, 280px) minmax(0, 1fr);
  gap: 14px;
}

.share-work-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-height: 340px;
  overflow-y: auto;
  padding-right: 4px;
}

.share-work-btn {
  width: 100%;
  border: 1px solid rgba(148,163,184,0.22);
  background: #ffffff;
  border-radius: 12px;
  padding: 12px;
  text-align: left;
  display: flex;
  flex-direction: column;
  gap: 4px;
  cursor: pointer;
  transition: all var(--transition);
}

.share-work-btn strong {
  font-size: 0.82rem;
  color: var(--text-bright);
}

.share-work-btn span {
  font-size: 0.74rem;
  color: var(--text-secondary);
}

.share-work-btn:hover,
.share-work-btn.active {
  background: rgba(37,99,235,0.06);
  border-color: rgba(37,99,235,0.28);
  box-shadow: var(--shadow-sm);
}

.class-toolbar {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  align-items: center;
  margin-bottom: 14px;
}

.class-card {
  background: linear-gradient(180deg, rgba(255,255,255,0.98), rgba(248,250,252,0.95));
  border: 1px solid rgba(148,163,184,0.22);
  border-radius: 16px;
  padding: 16px;
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: all var(--transition);
}

.class-card:hover,
.class-card.active {
  transform: translateY(-2px);
  border-color: rgba(37,99,235,0.28);
  box-shadow: var(--shadow-glow);
}

.student-picker-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-height: 320px;
  overflow-y: auto;
}

.profile-student-btn {
  width: 100%;
  border: 1px solid rgba(148,163,184,0.22);
  background: #ffffff;
  border-radius: 12px;
  padding: 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  text-align: left;
  cursor: pointer;
  transition: all var(--transition);
}

.profile-student-btn strong {
  font-size: 0.82rem;
  color: var(--text-bright);
}

.profile-student-btn span {
  font-size: 0.74rem;
  color: var(--text-secondary);
}

.profile-student-btn:hover,
.profile-student-btn.active {
  background: rgba(37,99,235,0.06);
  border-color: rgba(37,99,235,0.28);
  box-shadow: var(--shadow-sm);
}

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

  .class-toolbar {
    grid-template-columns: 1fr 1fr;
  }

  .a4-paper {
    min-height: auto;
    padding: 22px 18px;
  }
}

@media (max-width: 600px) {
  .image-card-grid,
  .class-toolbar {
    grid-template-columns: 1fr;
  }

  .a4-preview-head,
  .a4-paper-brand,
  .profile-student-btn {
    flex-direction: column;
    align-items: flex-start;
  }
}