/* ===== ROOT VARIABLES ===== */
:root {
  --bg: #0a0a0f;
  --bg2: #111118;
  --surface: rgba(255,255,255,0.04);
  --surface-hover: rgba(255,255,255,0.07);
  --border: rgba(255,255,255,0.08);
  --accent: #7c3aed;
  --accent2: #a855f7;
  --accent-glow: rgba(124,58,237,0.35);
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --text: #f1f5f9;
  --text-muted: #94a3b8;
  --text-dim: #475569;
  --sidebar-w: 240px;
  --topbar-h: 64px;
  --radius: 14px;
  --radius-sm: 8px;
  --shadow: 0 8px 32px rgba(0,0,0,0.4);
  --font: 'Inter', sans-serif;
  --mono: 'JetBrains Mono', monospace;
}

/* ===== RESET ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; overflow: hidden; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  font-size: 14px;
  line-height: 1.6;
}
a { color: var(--accent2); text-decoration: none; }
button { cursor: pointer; font-family: var(--font); border: none; outline: none; }
input, select, textarea { font-family: var(--font); outline: none; }
canvas { position: fixed; inset: 0; z-index: 0; pointer-events: none; }

/* ===== UTILS ===== */
.hidden { display: none !important; }
.page { position: fixed; inset: 0; z-index: 1; }
.page.active { display: flex; }

/* ===== GLASS CARD ===== */
.glass-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  padding: 24px;
  box-shadow: var(--shadow);
}

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 10px 22px; border-radius: var(--radius-sm);
  font-size: 14px; font-weight: 600;
  transition: all 0.2s ease;
}
.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #fff;
  box-shadow: 0 4px 20px var(--accent-glow);
}
.btn-primary:hover { transform: translateY(-1px); box-shadow: 0 6px 28px var(--accent-glow); }
.btn-outline {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}
.btn-outline:hover { background: var(--surface-hover); }
.btn-danger { background: var(--danger); color: #fff; }
.btn-full { width: 100%; }
.btn-loader {
  width: 16px; height: 16px;
  border: 2px solid rgba(255,255,255,0.3);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

/* ===== FORMS ===== */
.form-group { display: flex; flex-direction: column; gap: 8px; margin-bottom: 18px; }
.form-group label { font-size: 13px; font-weight: 500; color: var(--text-muted); }
.form-row { display: flex; gap: 16px; }
.form-row.two-col > * { flex: 1; }
.input-wrapper {
  display: flex; align-items: center; gap: 10px;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 10px 14px;
  transition: border-color 0.2s;
}
.input-wrapper:focus-within { border-color: var(--accent); }
.input-wrapper input {
  flex: 1; background: transparent; border: none;
  color: var(--text); font-size: 14px;
}
.input-wrapper input::placeholder { color: var(--text-dim); }
.input-icon { font-size: 16px; }
.error-msg {
  background: rgba(239,68,68,0.1); border: 1px solid rgba(239,68,68,0.3);
  color: var(--danger); border-radius: var(--radius-sm);
  padding: 10px 14px; font-size: 13px;
}
.range-slider {
  width: 100%; -webkit-appearance: none; appearance: none;
  height: 4px; background: var(--border); border-radius: 2px;
}
.range-slider::-webkit-slider-thumb {
  -webkit-appearance: none; width: 18px; height: 18px;
  border-radius: 50%; background: var(--accent); cursor: pointer;
  box-shadow: 0 0 8px var(--accent-glow);
}
.range-labels { display: flex; justify-content: space-between; color: var(--text-dim); font-size: 11px; }

/* ===== LOGIN ===== */
#page-login {
  align-items: center; justify-content: center;
  background: var(--bg);
}
.login-container { position: relative; z-index: 2; width: 100%; max-width: 420px; padding: 20px; }
.login-glow {
  position: absolute; top: 50%; left: 50%; transform: translate(-50%,-50%);
  width: 500px; height: 500px; pointer-events: none;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
}
.login-card { padding: 40px; }
.login-logo { text-align: center; margin-bottom: 32px; }
.logo-icon { font-size: 48px; line-height: 1; }
.logo-text { font-size: 28px; font-weight: 800; background: linear-gradient(135deg,#fff,var(--accent2)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.logo-sub { color: var(--text-muted); font-size: 13px; margin-top: 4px; }
.login-hint { text-align: center; color: var(--text-dim); font-size: 12px; margin-top: 16px; }
.login-hint code { font-family: var(--mono); color: var(--accent2); }

/* ===== SIDEBAR ===== */
#page-app { display: flex; width: 100%; height: 100%; z-index: 1; }
.sidebar {
  width: var(--sidebar-w); height: 100%;
  background: rgba(10,10,15,0.95);
  border-right: 1px solid var(--border);
  display: flex; flex-direction: column;
  flex-shrink: 0;
  backdrop-filter: blur(20px);
  z-index: 10;
}
.sidebar-header {
  padding: 20px 16px;
  display: flex; align-items: center; justify-content: space-between;
  border-bottom: 1px solid var(--border);
}
.sidebar-logo { display: flex; align-items: center; gap: 10px; }
.logo-icon-sm { font-size: 22px; }
.sidebar-brand { font-size: 18px; font-weight: 800; background: linear-gradient(135deg,#fff,var(--accent2)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.sidebar-toggle { background: none; display: flex; flex-direction: column; gap: 4px; padding: 4px; }
.sidebar-toggle span { display: block; width: 18px; height: 2px; background: var(--text-muted); border-radius: 2px; }
.sidebar-nav { flex: 1; padding: 12px 8px; display: flex; flex-direction: column; gap: 2px; overflow-y: auto; }
.nav-item {
  display: flex; align-items: center; gap: 12px;
  padding: 11px 14px; border-radius: var(--radius-sm);
  background: none; color: var(--text-muted);
  font-size: 14px; font-weight: 500;
  transition: all 0.18s ease; text-align: left; width: 100%;
}
.nav-item:hover { background: var(--surface-hover); color: var(--text); }
.nav-item.active { background: linear-gradient(135deg,rgba(124,58,237,0.25),rgba(168,85,247,0.15)); color: var(--text); border: 1px solid rgba(124,58,237,0.3); }
.nav-icon { font-size: 18px; flex-shrink: 0; }
.sidebar-footer {
  padding: 16px; border-top: 1px solid var(--border);
  display: flex; align-items: center; gap: 10px;
}
.user-pill { display: flex; align-items: center; gap: 10px; flex: 1; overflow: hidden; }
.user-avatar {
  width: 36px; height: 36px; border-radius: 50%; flex-shrink: 0;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 15px; color: #fff;
}
.user-info { display: flex; flex-direction: column; overflow: hidden; }
.user-name { font-size: 13px; font-weight: 600; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.user-role { font-size: 11px; color: var(--accent2); }
.btn-logout {
  background: none; color: var(--text-muted); font-size: 18px;
  padding: 6px; border-radius: 6px; transition: color 0.2s;
}
.btn-logout:hover { color: var(--danger); }

/* ===== MAIN CONTENT ===== */
.main-content { flex: 1; display: flex; flex-direction: column; overflow: hidden; }
.topbar {
  height: var(--topbar-h); padding: 0 28px;
  display: flex; align-items: center; justify-content: space-between;
  border-bottom: 1px solid var(--border); flex-shrink: 0;
  background: rgba(10,10,15,0.6); backdrop-filter: blur(12px);
}
.page-title { font-size: 18px; font-weight: 700; }
.breadcrumb { font-size: 12px; color: var(--text-dim); margin-top: 2px; }
.api-status { display: flex; align-items: center; gap: 8px; font-size: 13px; color: var(--text-muted); }
.status-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--warning); animation: pulse 2s infinite; }
.status-dot.online { background: var(--success); animation: none; }
.status-dot.offline { background: var(--danger); animation: none; }

/* ===== VIEWS ===== */
.view { flex: 1; overflow-y: auto; padding: 24px 28px; }
.view.hidden { display: none !important; }
.card-title { font-size: 16px; font-weight: 700; margin-bottom: 4px; }
.card-subtitle { font-size: 13px; color: var(--text-muted); margin-bottom: 20px; }

/* ===== STATS ===== */
.stats-row { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; margin-bottom: 24px; }
.stat-card { display: flex; align-items: center; gap: 16px; padding: 20px; }
.stat-icon { font-size: 32px; }
.stat-value { font-size: 26px; font-weight: 800; }
.stat-label { font-size: 12px; color: var(--text-muted); margin-top: 2px; }

/* ===== DASHBOARD ===== */
.dashboard-grid { display: grid; grid-template-columns: 1fr 1.5fr; gap: 16px; }
.quick-actions { display: flex; flex-direction: column; gap: 10px; margin-top: 12px; }
.qa-btn {
  display: flex; align-items: center; gap: 12px;
  background: var(--surface-hover); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 14px 16px;
  color: var(--text); font-size: 14px; font-weight: 500;
  transition: all 0.2s;
}
.qa-btn:hover { border-color: var(--accent); background: rgba(124,58,237,0.1); transform: translateX(4px); }
.qa-icon { font-size: 20px; }
.recent-list { display: flex; flex-direction: column; gap: 10px; margin-top: 12px; }
.recent-item {
  display: flex; align-items: center; gap: 12px;
  padding: 12px; border-radius: var(--radius-sm);
  background: var(--surface-hover); border: 1px solid var(--border);
}
.empty-state { color: var(--text-dim); font-size: 13px; padding: 20px; text-align: center; }

/* ===== UPLOAD ===== */
.upload-container { display: grid; grid-template-columns: 1.2fr 1fr; gap: 16px; }
.subject-pills { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 8px; }
.pill {
  padding: 6px 16px; border-radius: 100px;
  border: 1px solid var(--border); background: var(--surface);
  color: var(--text-muted); font-size: 13px; cursor: pointer;
  transition: all 0.18s;
}
.pill:hover { border-color: var(--accent); color: var(--text); }
.pill.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.drop-zone {
  border: 2px dashed var(--border); border-radius: var(--radius);
  padding: 40px 20px; text-align: center; cursor: pointer;
  transition: all 0.2s; margin: 16px 0;
}
.drop-zone.drag-over { border-color: var(--accent); background: rgba(124,58,237,0.08); }
.drop-icon { font-size: 40px; margin-bottom: 12px; }
.drop-zone h4 { font-size: 15px; font-weight: 600; margin-bottom: 6px; }
.drop-zone p { color: var(--text-muted); font-size: 13px; margin-bottom: 14px; }
.upload-queue { display: flex; flex-direction: column; gap: 8px; margin-bottom: 16px; }
.upload-item {
  display: flex; align-items: center; gap: 12px;
  padding: 10px 14px; background: var(--surface);
  border: 1px solid var(--border); border-radius: var(--radius-sm);
}
.upload-item-name { flex: 1; font-size: 13px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.upload-item-size { color: var(--text-muted); font-size: 12px; }
.upload-item-status { font-size: 14px; }
.upload-progress { height: 3px; background: var(--border); border-radius: 2px; margin-top: 6px; }
.upload-progress-fill { height: 100%; background: var(--accent); border-radius: 2px; transition: width 0.4s; }
.indexed-list { display: flex; flex-direction: column; gap: 8px; margin-top: 12px; }
.indexed-item {
  display: flex; align-items: center; gap: 12px;
  padding: 10px 14px; background: var(--surface);
  border: 1px solid var(--border); border-radius: var(--radius-sm);
}
.indexed-icon { font-size: 20px; }
.indexed-info { flex: 1; }
.indexed-name { font-size: 13px; font-weight: 500; }
.indexed-meta { font-size: 11px; color: var(--text-muted); }
.indexed-badge {
  font-size: 11px; padding: 2px 8px; border-radius: 100px;
  background: rgba(16,185,129,0.15); color: var(--success); border: 1px solid rgba(16,185,129,0.3);
}

/* ===== GENERATE ===== */
.generate-container { max-width: 720px; margin: 0 auto; }
.difficulty-btns { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 8px; }
.diff-btn {
  padding: 8px 18px; border-radius: 100px;
  border: 1px solid var(--border); background: var(--surface);
  color: var(--text-muted); font-size: 13px;
  transition: all 0.18s;
}
.diff-btn:hover { border-color: var(--accent); color: var(--text); }
.diff-btn.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.topic-suggestions { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 8px; }
.topic-chip {
  padding: 4px 12px; border-radius: 100px;
  background: rgba(124,58,237,0.12); border: 1px solid rgba(124,58,237,0.25);
  color: var(--accent2); font-size: 12px; cursor: pointer; transition: all 0.15s;
}
.topic-chip:hover { background: rgba(124,58,237,0.25); }
.gen-status { margin-top: 24px; }
.gen-progress { display: flex; flex-direction: column; gap: 10px; }
.progress-step { display: flex; align-items: center; gap: 12px; color: var(--text-dim); font-size: 13px; }
.progress-step.active { color: var(--text); }
.progress-step.done { color: var(--success); }
.step-dot {
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--border); flex-shrink: 0; transition: all 0.3s;
}
.progress-step.active .step-dot { background: var(--accent); box-shadow: 0 0 8px var(--accent-glow); animation: pulse 1s infinite; }
.progress-step.done .step-dot { background: var(--success); }

/* ===== EXAM ===== */
.exam-empty { max-width: 400px; margin: 60px auto; text-align: center; padding: 48px; }
.exam-empty-icon { font-size: 56px; margin-bottom: 16px; }
.exam-empty h3 { font-size: 20px; font-weight: 700; margin-bottom: 8px; }
.exam-empty p { color: var(--text-muted); margin-bottom: 24px; }
.exam-header {
  display: flex; flex-direction: column; padding: 16px 24px; margin-bottom: 20px;
}
.exam-meta { display: flex; gap: 8px; flex: 1; }
.subject-badge, .diff-badge {
  padding: 4px 12px; border-radius: 100px; font-size: 12px; font-weight: 600;
}
.subject-badge { background: rgba(124,58,237,0.2); color: var(--accent2); border: 1px solid rgba(124,58,237,0.3); }
.diff-badge { background: rgba(245,158,11,0.2); color: var(--warning); border: 1px solid rgba(245,158,11,0.3); }
.exam-timer { font-family: var(--mono); font-size: 22px; font-weight: 700; color: var(--accent2); }

.exam-body { 
  display: grid; 
  grid-template-columns: 240px 1fr; 
  gap: 24px; 
  margin-bottom: 16px; 
}
.question-nav { 
  display: grid; 
  grid-template-columns: repeat(5, 1fr); 
  gap: 8px; 
  align-content: start;
  background: var(--surface);
  padding: 16px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}
.qnav-btn {
  aspect-ratio: 1 / 1;
  width: 100%;
  padding: 0;
  display: flex; align-items: center; justify-content: center;
  border-radius: 4px;
  background: rgba(255,255,255,0.05); border: 1px solid var(--border);
  color: var(--text-muted); font-size: 13px; font-weight: 600;
  transition: all 0.2s; cursor: pointer;
}
.qnav-btn:hover { border-color: var(--accent); background: rgba(124,58,237,0.1); }
.qnav-btn.answered { border-color: var(--success); color: var(--success); background: rgba(16,185,129,0.1); }
.qnav-btn.current { background: var(--accent); border-color: var(--accent); color: #fff; transform: scale(1.1); box-shadow: 0 4px 12px var(--accent-glow); z-index: 2; position: relative; }
.question-card { padding: 28px; }
.q-number { font-size: 12px; color: var(--text-muted); margin-bottom: 8px; font-weight: 600; letter-spacing: 0.5px; }
.q-text { font-size: 16px; font-weight: 600; line-height: 1.6; margin-bottom: 24px; }
.options-list { display: flex; flex-direction: column; gap: 10px; }
.option-btn {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 18px; border-radius: var(--radius-sm);
  background: var(--surface); border: 1px solid var(--border);
  color: var(--text); font-size: 14px; text-align: left;
  transition: all 0.18s; width: 100%;
}
.option-btn:hover { border-color: var(--accent); background: rgba(124,58,237,0.08); }
.option-btn.selected { border-color: var(--accent); background: rgba(124,58,237,0.15); color: #fff; }
.option-btn.correct { border-color: var(--success); background: rgba(16,185,129,0.15); }
.option-btn.wrong { border-color: var(--danger); background: rgba(239,68,68,0.15); }
.option-key { font-family: var(--mono); font-weight: 700; font-size: 13px; color: var(--accent2); flex-shrink: 0; }
.exam-footer { display: flex; gap: 12px; padding: 16px 24px; align-items: center; }
.exam-footer .btn-danger { margin-left: auto; }

/* ===== RESULTS ===== */
.results-hero { display: flex; align-items: center; gap: 40px; padding: 40px; margin-bottom: 20px; flex-wrap: wrap; }
.results-score-ring { position: relative; width: 140px; height: 140px; flex-shrink: 0; }
.results-score-ring svg { width: 100%; height: 100%; transform: rotate(-90deg); }
.ring-bg { fill: none; stroke: var(--border); stroke-width: 10; }
.ring-fill { fill: none; stroke: url(#ringGradient); stroke-width: 10; stroke-linecap: round; transition: stroke-dashoffset 1.2s cubic-bezier(0.4,0,0.2,1); }
.ring-text { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; }
.ring-score { font-size: 24px; font-weight: 800; }
.ring-pct { font-size: 13px; color: var(--accent2); }
.results-meta h3 { font-size: 22px; font-weight: 800; margin-bottom: 8px; }
.results-meta p { color: var(--text-muted); margin-bottom: 20px; }
.results-actions { display: flex; gap: 10px; flex-wrap: wrap; }
.results-review { display: flex; flex-direction: column; gap: 14px; }
.review-card { padding: 20px; border-radius: var(--radius); border: 1px solid var(--border); background: var(--surface); }
.review-card.correct-card { border-color: rgba(16,185,129,0.3); }
.review-card.wrong-card { border-color: rgba(239,68,68,0.3); }
.review-q { font-weight: 600; margin-bottom: 10px; }
.review-answer { font-size: 13px; color: var(--text-muted); margin-bottom: 4px; }
.review-explanation { font-size: 13px; color: var(--text-muted); margin-top: 10px; padding-top: 10px; border-top: 1px solid var(--border); }

/* ===== ANALYTICS ===== */
.analytics-container { display: flex; flex-direction: column; gap: 20px; }
.charts-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.chart-card canvas { max-height: 220px; }
.chart-card.wide { grid-column: 1 / -1; }
.chart-card.wide canvas { max-height: 200px; }

/* ===== TABLE ===== */
.table-wrapper { overflow-x: auto; margin-top: 16px; }
.data-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.data-table th { padding: 10px 14px; text-align: left; color: var(--text-muted); font-weight: 600; border-bottom: 1px solid var(--border); white-space: nowrap; }
.data-table td { padding: 10px 14px; border-bottom: 1px solid rgba(255,255,255,0.04); }
.data-table tr:hover td { background: var(--surface-hover); }

/* ===== ADMIN ===== */
.admin-container { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.user-list { display: flex; flex-direction: column; gap: 8px; margin: 12px 0; }
.user-item { display: flex; align-items: center; gap: 12px; padding: 10px 14px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-sm); }
.add-user-form { margin-top: 20px; padding-top: 20px; border-top: 1px solid var(--border); }
.add-user-form h4 { font-size: 14px; font-weight: 600; margin-bottom: 14px; }

/* ===== TOAST ===== */
.toast-container { position: fixed; bottom: 24px; right: 24px; z-index: 9999; display: flex; flex-direction: column; gap: 8px; }
.toast {
  padding: 12px 20px; border-radius: var(--radius-sm);
  background: var(--surface); border: 1px solid var(--border);
  backdrop-filter: blur(16px); font-size: 14px;
  box-shadow: var(--shadow); animation: slideUp 0.3s ease;
  max-width: 320px;
}
.toast.success { border-color: rgba(16,185,129,0.4); }
.toast.error { border-color: rgba(239,68,68,0.4); }
.toast.info { border-color: rgba(124,58,237,0.4); }
.upload-subject-select { margin-bottom: 16px; }

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--accent); }