/* ==========================================================================
   課堂即席多語翻譯 — Design System
   ========================================================================== */
@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@400;500;600;700;800&family=Inter:wght@400;500;600;700&display=swap');

:root {
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'PingFang TC', 'Noto Sans TC', system-ui, sans-serif;
  --font-display: 'Outfit', -apple-system, BlinkMacSystemFont, 'PingFang TC', 'Noto Sans TC', system-ui, sans-serif;
  --font-mono: ui-monospace, 'SF Mono', Menlo, Consolas, monospace;

  /* Youthful Cyber / Deep Slate Dark Palette */
  --h-brand: 252;
  --h-accent: 174;
  --brand: hsl(252 92% 67%);
  --brand-strong: hsl(252 95% 60%);
  --brand-neon: #8b5cf6;
  --accent: hsl(174 95% 50%);
  --accent-cyan: #06b6d4;
  --accent-pink: #ec4899;
  --grad: linear-gradient(135deg, #7c3aed 0%, #4f46e5 50%, #06b6d4 100%);
  --grad-warm: linear-gradient(135deg, #f43f5e 0%, #fb923c 100%);
  --grad-subtle: linear-gradient(180deg, rgba(255,255,255,0.06) 0%, rgba(255,255,255,0.02) 100%);
  --ok: #10b981;
  --warn: #f59e0b;
  --danger: #ef4444;

  /* Deep OLED / Cinema Dark Backgrounds (reduces eye strain for lectures) */
  --bg: #090a10;
  --bg-2: #0f111a;
  --surface: rgba(18, 20, 32, 0.72);
  --surface-solid: #121422;
  --surface-hi: rgba(28, 32, 50, 0.75);
  --border: rgba(255, 255, 255, 0.08);
  --border-hi: rgba(255, 255, 255, 0.16);
  --text: #f8fafc;
  --text-2: #94a3b8;
  --text-3: #64748b;
  --shadow: 0 12px 40px -10px rgba(0, 0, 0, 0.7), 0 2px 10px rgba(0, 0, 0, 0.4);
  --glow: 0 0 0 1px rgba(124, 58, 237, 0.35), 0 10px 30px -5px rgba(124, 58, 237, 0.4);
  --glow-accent: 0 0 20px -3px rgba(6, 182, 212, 0.35);

  --r-sm: 10px;
  --r: 16px;
  --r-lg: 24px;
  --ease: cubic-bezier(.16, 1, .3, 1);
  color-scheme: dark;
}

@media (prefers-color-scheme: light) {
  :root[data-theme="auto"] {
    --bg: hsl(228 40% 97%);
    --bg-2: hsl(228 36% 94%);
    --surface: hsl(0 0% 100% / .72);
    --surface-solid: hsl(0 0% 100%);
    --surface-hi: hsl(228 40% 96% / .9);
    --border: hsl(232 30% 30% / .10);
    --border-hi: hsl(232 30% 30% / .18);
    --text: hsl(232 36% 12%);
    --text-2: hsl(232 16% 34%);
    --text-3: hsl(232 10% 50%);
    --shadow: 0 10px 40px -16px hsl(232 40% 30% / .25), 0 2px 8px hsl(232 40% 30% / .08);
    color-scheme: light;
  }
}
:root[data-theme="light"] {
  --bg: hsl(228 40% 97%);
  --bg-2: hsl(228 36% 94%);
  --surface: hsl(0 0% 100% / .72);
  --surface-solid: hsl(0 0% 100%);
  --surface-hi: hsl(228 40% 96% / .9);
  --border: hsl(232 30% 30% / .10);
  --border-hi: hsl(232 30% 30% / .18);
  --text: hsl(232 36% 12%);
  --text-2: hsl(232 16% 34%);
  --text-3: hsl(232 10% 50%);
  --shadow: 0 10px 40px -16px hsl(232 40% 30% / .25), 0 2px 8px hsl(232 40% 30% / .08);
  color-scheme: light;
}

*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  min-height: 100dvh;
  -webkit-font-smoothing: antialiased;
  line-height: 1.55;
}
/* 背景光暈 */
body::before {
  content: '';
  position: fixed; inset: -20vmax;
  z-index: -1;
  background:
    radial-gradient(40vmax 40vmax at 12% 8%, hsl(258 90% 60% / .16), transparent 60%),
    radial-gradient(36vmax 36vmax at 88% 12%, hsl(188 92% 50% / .12), transparent 60%),
    radial-gradient(50vmax 40vmax at 50% 110%, hsl(222 92% 60% / .12), transparent 60%);
  animation: drift 28s ease-in-out infinite alternate;
  pointer-events: none;
}
@keyframes drift { to { transform: translate3d(2vmax, -2vmax, 0) rotate(4deg); } }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3, h4 { font-family: var(--font-display); letter-spacing: -.01em; margin: 0; }
code, kbd { font-family: var(--font-mono); font-size: .88em; background: var(--surface-hi); padding: .1em .4em; border-radius: 6px; }
::selection { background: hsl(var(--h-brand) 90% 66% / .35); }

/* ---------- layout ---------- */
.container { width: min(1200px, 100% - 32px); margin-inline: auto; }
.stack { display: flex; flex-direction: column; gap: var(--gap, 16px); }
.row { display: flex; align-items: center; gap: var(--gap, 12px); flex-wrap: wrap; }
.spacer { flex: 1; }
.grid { display: grid; gap: 20px; grid-template-columns: repeat(auto-fit, minmax(min(100%, var(--min, 340px)), 1fr)); }
.muted { color: var(--text-2); }
.faint { color: var(--text-3); font-size: .875rem; }
.hidden { display: none !important; }

/* ---------- topbar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 30;
  backdrop-filter: blur(18px) saturate(1.4);
  -webkit-backdrop-filter: blur(18px) saturate(1.4);
  background: hsl(232 30% 6% / .55);
  border-bottom: 1px solid var(--border);
}
:root[data-theme="light"] .topbar { background: hsl(0 0% 100% / .6); }
.topbar .container { display: flex; align-items: center; gap: 16px; height: 64px; }
.brand { display: flex; align-items: center; gap: 12px; font-family: var(--font-display); font-weight: 700; font-size: 1.08rem; color: var(--text); }
.brand:hover { text-decoration: none; }
.brand-logo {
  width: 36px; height: 36px; border-radius: 11px;
  background: var(--grad);
  display: grid; place-items: center;
  box-shadow: var(--glow);
  color: white; font-size: 1.1rem;
}
.brand small { display: block; font-family: var(--font-sans); font-weight: 500; font-size: .72rem; color: var(--text-3); letter-spacing: .04em; }
.nav { display: flex; gap: 4px; }
.nav a { padding: 8px 14px; border-radius: 10px; color: var(--text-2); font-weight: 500; font-size: .92rem; transition: .2s var(--ease); }
.nav a:hover { background: var(--surface-hi); color: var(--text); text-decoration: none; }
.nav a.active { background: var(--surface-hi); color: var(--text); box-shadow: inset 0 0 0 1px var(--border-hi); }

/* ---------- card ---------- */
.card {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  padding: 24px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(20px) saturate(1.3);
  -webkit-backdrop-filter: blur(20px) saturate(1.3);
  transition: border-color .3s var(--ease), transform .3s var(--ease);
  animation: rise .5s var(--ease) both;
}
.card:hover { border-color: var(--border-hi); }
.card-head { display: flex; align-items: flex-start; gap: 14px; margin-bottom: 20px; }
.card-icon {
  flex: none; width: 44px; height: 44px; border-radius: 13px;
  display: grid; place-items: center; font-size: 1.3rem;
  background: linear-gradient(135deg, hsl(var(--h, 258) 90% 60% / .22), hsl(var(--h, 258) 90% 60% / .06));
  border: 1px solid hsl(var(--h, 258) 90% 70% / .25);
}
.card-head h2 { font-size: 1.14rem; font-weight: 650; }
.card-head p { margin: 2px 0 0; color: var(--text-3); font-size: .86rem; }
@keyframes rise { from { opacity: 0; transform: translateY(12px); } }

/* ---------- form ---------- */
.field { display: flex; flex-direction: column; gap: 7px; }
.field > label, .label { font-size: .82rem; font-weight: 600; color: var(--text-2); letter-spacing: .02em; display: flex; align-items: center; gap: 8px; }
.field .hint { font-size: .78rem; color: var(--text-3); }
.input, .select, .textarea {
  width: 100%;
  font: inherit; font-size: .94rem;
  color: var(--text);
  background: hsl(232 30% 4% / .45);
  border: 1px solid var(--border-hi);
  border-radius: var(--r-sm);
  padding: 11px 14px;
  transition: border-color .2s, box-shadow .2s, background .2s;
  outline: none;
}
:root[data-theme="light"] .input, :root[data-theme="light"] .select, :root[data-theme="light"] .textarea { background: hsl(0 0% 100% / .8); }
.input:focus, .select:focus, .textarea:focus { border-color: var(--brand); box-shadow: 0 0 0 4px hsl(var(--h-brand) 90% 66% / .18); }
.textarea { min-height: 120px; resize: vertical; font-family: var(--font-mono); font-size: .84rem; line-height: 1.6; }
.select { appearance: none; background-image: linear-gradient(45deg, transparent 50%, var(--text-3) 50%), linear-gradient(135deg, var(--text-3) 50%, transparent 50%); background-position: calc(100% - 18px) 50%, calc(100% - 13px) 50%; background-size: 5px 5px; background-repeat: no-repeat; padding-right: 36px; }
.select option { background: var(--surface-solid); color: var(--text); }
.input-group { display: flex; gap: 8px; }
.input-group .input { flex: 1; }

/* range slider */
.range-wrap { display: flex; align-items: center; gap: 14px; }
.range-wrap output { min-width: 56px; text-align: right; font-family: var(--font-mono); font-size: .88rem; color: var(--text); background: var(--surface-hi); border: 1px solid var(--border); padding: 4px 8px; border-radius: 8px; }
input[type=range] {
  -webkit-appearance: none; appearance: none; flex: 1; height: 6px; border-radius: 99px;
  background: linear-gradient(90deg, var(--brand) 0%, var(--accent) var(--p, 50%), var(--border-hi) var(--p, 50%));
  outline: none;
}
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 20px; height: 20px; border-radius: 50%;
  background: white; border: 3px solid var(--brand); box-shadow: 0 2px 10px hsl(258 90% 50% / .5);
  cursor: grab; transition: transform .15s;
}
input[type=range]::-webkit-slider-thumb:active { transform: scale(1.18); cursor: grabbing; }
input[type=range]::-moz-range-thumb { width: 16px; height: 16px; border-radius: 50%; background: white; border: 3px solid var(--brand); }

/* switch */
.switch { position: relative; display: inline-flex; align-items: center; gap: 10px; cursor: pointer; user-select: none; }
.switch input { position: absolute; opacity: 0; pointer-events: none; }
.switch .track { width: 44px; height: 26px; border-radius: 99px; background: var(--border-hi); position: relative; transition: background .25s var(--ease); flex: none; }
.switch .track::after { content: ''; position: absolute; top: 3px; left: 3px; width: 20px; height: 20px; border-radius: 50%; background: white; box-shadow: 0 2px 6px hsl(0 0% 0% / .3); transition: transform .3s var(--ease); }
.switch input:checked + .track { background: var(--grad); }
.switch input:checked + .track::after { transform: translateX(18px); }
.switch input:focus-visible + .track { box-shadow: 0 0 0 4px hsl(var(--h-brand) 90% 66% / .3); }

/* ---------- buttons ---------- */
.btn {
  --bh: 42px;
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: var(--bh); padding: 0 18px;
  font: inherit; font-weight: 600; font-size: .92rem;
  color: var(--text);
  background: var(--surface-hi);
  border: 1px solid var(--border-hi);
  border-radius: 12px;
  cursor: pointer;
  transition: transform .15s var(--ease), box-shadow .25s var(--ease), background .25s, border-color .25s, opacity .2s;
  white-space: nowrap;
  text-decoration: none !important;
}
.btn:hover { border-color: var(--brand); transform: translateY(-1px); }
.btn:active { transform: translateY(0) scale(.98); }
.btn:disabled { opacity: .5; cursor: not-allowed; transform: none; }
.btn-primary { background: var(--grad); border-color: transparent; color: white; box-shadow: 0 8px 24px -8px hsl(240 90% 60% / .6); }
.btn-primary:hover { box-shadow: 0 12px 30px -8px hsl(240 90% 60% / .75); border-color: transparent; }
.btn-danger { background: hsl(352 86% 62% / .14); border-color: hsl(352 86% 62% / .4); color: hsl(352 90% 72%); }
.btn-danger:hover { border-color: var(--danger); background: hsl(352 86% 62% / .22); }
.btn-ghost { background: transparent; border-color: transparent; color: var(--text-2); }
.btn-ghost:hover { background: var(--surface-hi); color: var(--text); border-color: var(--border); }
.btn-sm { --bh: 34px; padding: 0 12px; font-size: .84rem; border-radius: 10px; }
.btn-lg { --bh: 54px; padding: 0 28px; font-size: 1.04rem; border-radius: 16px; }
.btn-icon { width: var(--bh); padding: 0; }
.btn .spin { width: 16px; height: 16px; border: 2px solid currentColor; border-right-color: transparent; border-radius: 50%; animation: spin .7s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- badges & status ---------- */
.badge { display: inline-flex; align-items: center; gap: 6px; padding: 4px 10px; border-radius: 99px; font-size: .76rem; font-weight: 600; background: var(--surface-hi); border: 1px solid var(--border); color: var(--text-2); }
.badge.ok { color: var(--ok); background: hsl(152 68% 48% / .12); border-color: hsl(152 68% 48% / .3); }
.badge.warn { color: var(--warn); background: hsl(38 96% 56% / .12); border-color: hsl(38 96% 56% / .3); }
.badge.danger { color: var(--danger); background: hsl(352 86% 62% / .12); border-color: hsl(352 86% 62% / .3); }
.badge.live { color: white; background: var(--grad-warm); border-color: transparent; }
.dot { width: 10px; height: 10px; border-radius: 50%; background: var(--text-3); flex: none; display: inline-block; }
.dot.ok { background: var(--ok); box-shadow: 0 0 0 4px hsl(152 68% 48% / .18), 0 0 14px var(--ok); }
.dot.danger { background: var(--danger); box-shadow: 0 0 0 4px hsl(352 86% 62% / .18), 0 0 14px var(--danger); }
.dot.warn { background: var(--warn); box-shadow: 0 0 0 4px hsl(38 96% 56% / .18); }
.dot.pulse { animation: pulse 1.6s ease-in-out infinite; }
@keyframes pulse { 50% { opacity: .45; } }

/* ---------- stats ---------- */
.stat { padding: 18px; border-radius: var(--r); background: var(--surface-hi); border: 1px solid var(--border); }
.stat .v { font-family: var(--font-display); font-size: 2rem; font-weight: 700; line-height: 1.1; background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.stat .k { font-size: .78rem; color: var(--text-3); font-weight: 600; letter-spacing: .04em; text-transform: uppercase; }

/* ---------- table ---------- */
.table-wrap { overflow-x: auto; border-radius: var(--r); border: 1px solid var(--border); }
table.table { width: 100%; border-collapse: collapse; font-size: .88rem; }
.table th { text-align: left; font-weight: 600; color: var(--text-3); font-size: .75rem; letter-spacing: .05em; text-transform: uppercase; padding: 12px 14px; background: var(--surface-hi); }
.table td { padding: 12px 14px; border-top: 1px solid var(--border); vertical-align: middle; }
.table tr:hover td { background: hsl(232 30% 50% / .04); }

/* ---------- toast ---------- */
.toasts { position: fixed; bottom: 22px; left: 50%; transform: translateX(-50%); display: flex; flex-direction: column; gap: 10px; z-index: 100; pointer-events: none; width: min(420px, 92vw); }
.toast {
  pointer-events: auto;
  padding: 13px 18px; border-radius: 14px;
  background: var(--surface-solid); border: 1px solid var(--border-hi); box-shadow: var(--shadow);
  font-size: .9rem; font-weight: 500;
  display: flex; align-items: center; gap: 10px;
  animation: toast-in .35s var(--ease) both;
}
.toast.ok { border-color: hsl(152 68% 48% / .5); }
.toast.err { border-color: hsl(352 86% 62% / .55); }
.toast.out { animation: toast-out .3s var(--ease) forwards; }
@keyframes toast-in { from { opacity: 0; transform: translateY(16px) scale(.96); } }
@keyframes toast-out { to { opacity: 0; transform: translateY(10px) scale(.96); } }

/* ---------- auth screen ---------- */
.auth-screen { min-height: 100dvh; display: grid; place-items: center; padding: 24px; }
.auth-card { width: min(420px, 100%); text-align: center; padding: 40px 32px; }
.auth-card .brand-logo { width: 64px; height: 64px; border-radius: 20px; font-size: 1.8rem; margin: 0 auto 18px; }
.auth-card h1 { font-size: 1.6rem; margin-bottom: 6px; }
.auth-card form { margin-top: 26px; text-align: left; }

/* ---------- misc ---------- */
.divider { height: 1px; background: var(--border); margin: 6px 0; border: 0; }
.kbd-chip { font-family: var(--font-mono); font-size: .78rem; padding: 2px 8px; border-radius: 6px; background: var(--surface-hi); border: 1px solid var(--border); color: var(--text-2); }
.grad-text { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.empty { text-align: center; color: var(--text-3); padding: 36px 16px; font-size: .92rem; }
.empty .ico { font-size: 2rem; display: block; margin-bottom: 8px; opacity: .7; }

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

/* ---------- PWA Install Banner ---------- */
.pwa-install-banner {
  position: fixed;
  left: 50%;
  bottom: 24px;
  transform: translateX(-50%) translateY(140%);
  width: min(460px, calc(100% - 24px));
  z-index: 99;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 16px;
  border-radius: 18px;
  background: rgba(18, 20, 32, 0.94);
  border: 1px solid rgba(139, 92, 246, 0.45);
  box-shadow: 0 16px 45px rgba(0, 0, 0, 0.7), 0 0 25px rgba(124, 58, 237, 0.25);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  transition: transform .4s var(--ease), opacity .3s ease;
  opacity: 0;
  pointer-events: none;
}
.pwa-install-banner.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
  pointer-events: auto;
}
.pwa-banner-content {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}
.pwa-banner-icon {
  font-size: 1.5rem;
  flex: none;
}
.pwa-banner-text {
  display: flex;
  flex-direction: column;
  min-width: 0;
}
.pwa-banner-text strong {
  font-size: .92rem;
  color: #ffffff;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.pwa-banner-text span {
  font-size: .78rem;
  color: #94a3b8;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.pwa-banner-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: none;
}