/* ═══════════════════════════════════════════
   VocabTracker · 暗夜隽永
   Deep navy + coral red + sky blue
   ═══════════════════════════════════════════ */

:root {
  /* Palette */
  --color-bg:            #0F1724;
  --color-bg-elevated:   #151E2D;
  --color-card:          #1A2332;
  --color-card-hover:    #1F293A;
  --color-text:          #E2E4E9;
  --color-text-secondary:#9498A0;
  --color-text-muted:    #636872;
  --color-primary:       #F05050;   /* coral red */
  --color-primary-soft:  rgba(240,80,80,.12);
  --color-accent:        #50B0F0;   /* sky blue */
  --color-accent-soft:   rgba(80,176,240,.12);
  --color-gold:          #F0C864;
  --color-gold-soft:     rgba(240,200,100,.12);
  --color-success:       #4ADE80;
  --color-success-soft:  rgba(74,222,128,.12);
  --color-danger:        #F05050;
  --color-danger-soft:   rgba(240,80,80,.12);
  --color-warning:       #F0A050;
  --color-stubborn:      #F05050;
  --color-border:        #252E3E;
  --color-border-light:  #2A3345;

  /* Typography */
  --font-body: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, -apple-system, sans-serif;
  --font-word: Georgia, "Times New Roman", "Songti SC", serif;
  --font-size-xs:  12px;
  --font-size-sm:  13px;
  --font-size-base:15px;
  --font-size-md:  18px;
  --font-size-lg:  22px;
  --font-size-xl:  28px;
  --font-size-word:44px;

  /* Spacing & Effects */
  --radius: 10px;
  --radius-sm: 6px;
  --shadow: 0 1px 2px rgba(0,0,0,.3);
  --shadow-md: 0 4px 16px rgba(0,0,0,.4);
}

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

html { background: var(--color-bg); }

body {
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-text);
  font-size: var(--font-size-base);
  line-height: 1.65;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

/* Global form element font reset — prevent browser defaults (e.g. 宋体) */
input, select, textarea, button, optgroup, datalist {
  font-family: var(--font-body);
}

/* Placeholder text always uses the body font — prevents Chinese
   placeholder glyphs from falling back to serif (宋体) when the
   input itself uses a word-spelling serif stack. */
input::placeholder,
textarea::placeholder {
  font-family: var(--font-body) !important;
  color: var(--color-text-muted);
  opacity: 1; /* Firefox ships with reduced opacity by default */
}

/* Only English word input (add-word form) uses serif for readability */
.word-spelling-input {
  font-family: var(--font-word) !important;
}

/* ── Layout ───────────────────────────── */

#app {
  max-width: 760px;
  margin: 0 auto;
  padding: 24px 20px 40px;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ── Header ───────────────────────────── */

header {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  padding: 16px 0 14px;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 28px;
}

.logo {
  font-size: 28px;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: .5px;
}

#main-nav {
  display: flex;
  gap: 2px;
  flex-wrap: wrap;
  justify-content: center;
}

#main-nav a {
  text-decoration: none;
  color: var(--color-text-secondary);
  padding: 7px 16px;
  border-radius: 20px;
  font-size: var(--font-size-base);
  font-weight: 500;
  transition: all .2s;
}

#main-nav a:hover { color: var(--color-text); background: rgba(255,255,255,.06); }
#main-nav a.active { background: var(--color-primary); color: #fff; }

#main-nav a.stubborn-link.active { background: var(--color-stubborn); }
#main-nav a.stubborn-link.has-stubborn:not(.active)::after {
  content: ' ·';
  color: var(--color-stubborn);
  font-weight: 700;
}

main#content { flex: 1; }

footer {
  text-align: center;
  padding: 24px 0 0;
  color: var(--color-text-muted);
  font-size: var(--font-size-xs);
  border-top: 1px solid var(--color-border);
  margin-top: 36px;
  letter-spacing: 1px;
}

/* ── Card ─────────────────────────────── */

.card {
  background: var(--color-card);
  border-radius: var(--radius);
  padding: 22px 24px;
  box-shadow: var(--shadow);
  margin-bottom: 14px;
  border: 1px solid var(--color-border);
}

/* ── Buttons ──────────────────────────── */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px 22px;
  border: none;
  border-radius: 8px;
  font-size: var(--font-size-base);
  font-weight: 600;
  cursor: pointer;
  transition: all .2s;
  font-family: var(--font-body);
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}
.btn-primary:hover { opacity: .88; transform: translateY(-1px); box-shadow: 0 4px 12px rgba(240,80,80,.3); }

.btn-success { background: var(--color-success); color: #000; }
.btn-success:hover { opacity: .85; }

.btn-danger { background: var(--color-danger); color: #fff; }
.btn-danger:hover { opacity: .85; }

.btn-outline {
  background: transparent;
  border: 1.5px solid var(--color-border-light);
  color: var(--color-text-secondary);
}
.btn-outline:hover { border-color: var(--color-text-muted); color: var(--color-text); }

.btn-accent {
  background: var(--color-accent);
  color: #000;
}
.btn-accent:hover { opacity: .85; }

.btn-sm { padding: 6px 14px; font-size: var(--font-size-sm); border-radius: 6px; }

/* ── Dashboard stats ──────────────────── */

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(145px, 1fr));
  gap: 10px;
}

.stat-card {
  background: var(--color-card);
  border-radius: var(--radius);
  padding: 18px 14px;
  box-shadow: var(--shadow);
  text-align: center;
  border: 1px solid var(--color-border);
}

.stat-card .number {
  font-size: 32px;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.1;
}

.stat-card .number.danger { color: var(--color-danger); }
.stat-card .number.gold { color: var(--color-gold); }

.stat-highlight {
  border-color: var(--color-gold);
  background: linear-gradient(135deg, rgba(240,200,100,.06), var(--color-card));
  cursor: pointer;
  transition: all .2s;
}
.stat-highlight:hover { transform: translateY(-2px); border-color: var(--color-gold); box-shadow: 0 4px 16px rgba(240,200,100,.12); }

.stat-card .label {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-top: 6px;
}

/* ── Page header ──────────────────────── */

.page-header { margin-bottom: 20px; }
.page-header h2 { font-size: var(--font-size-lg); font-weight: 700; }
.page-header .date { color: var(--color-text-secondary); font-size: var(--font-size-sm); margin-top: 4px; }

/* ── Empty state ──────────────────────── */

.empty-state {
  text-align: center;
  padding: 56px 20px;
  color: var(--color-text-muted);
}
.empty-state .icon { font-size: 48px; margin-bottom: 12px; opacity: .7; }
.empty-state p { margin-bottom: 16px; font-size: var(--font-size-base); }

/* ── Modal ────────────────────────────── */

.modal-overlay {
  position: fixed; top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0,0,0,.6);
  display: flex; align-items: center; justify-content: center;
  z-index: 100;
}
.modal {
  background: var(--color-card);
  border-radius: var(--radius);
  padding: 24px;
  max-width: 500px;
  width: 92%;
  max-height: 80vh;
  overflow-y: auto;
  border: 1px solid var(--color-border);
  box-shadow: 0 16px 48px rgba(0,0,0,.5);
}

/* ── Badges ───────────────────────────── */

.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 10px;
  font-size: 12px;
  font-weight: 600;
  background: rgba(255,255,255,.06);
  color: var(--color-text-secondary);
}
.badge-success { background: var(--color-success-soft); color: var(--color-success); }
.badge-pending { background: var(--color-gold-soft); color: var(--color-gold); }
.badge-info { background: var(--color-accent-soft); color: var(--color-accent); }
.badge-danger { background: var(--color-danger-soft); color: var(--color-danger); }

/* ═══════════════════════════════════════════
   STUDY PAGE — 背诵卡片（重点突出）
   ═══════════════════════════════════════════ */

.study-card {
  text-align: center;
  border: 1px solid var(--color-gold);
  background: linear-gradient(180deg, rgba(240,200,100,.04), var(--color-card));
  padding: 32px 24px !important;
  box-shadow: 0 0 24px rgba(240,200,100,.06);
}

.study-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}
.progress-text { font-size: var(--font-size-sm); color: var(--color-text-muted); }

.progress-bar {
  height: 3px;
  background: var(--color-border);
  border-radius: 2px;
  margin-bottom: 28px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: var(--color-gold);
  transition: width .4s ease;
  border-radius: 2px;
}

/* Word display */
.word-display { margin: 16px 0 24px; }

.word-spelling {
  font-family: var(--font-word);
  font-size: var(--font-size-word);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 6px;
  letter-spacing: 1px;
  line-height: 1.2;
}

.word-phonetic {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: 14px;
}

.word-meaning {
  margin: 18px 0;
  padding: 18px 20px;
  background: var(--color-gold-soft);
  border-radius: var(--radius-sm);
  border: 1px solid rgba(240,200,100,.15);
}
.meaning-text {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-gold);
}

.word-example {
  margin: 14px 0;
  padding: 14px 18px;
  background: rgba(255,255,255,.03);
  border-radius: var(--radius-sm);
  text-align: left;
  border-left: 3px solid var(--color-border-light);
}
.example-label { font-size: var(--font-size-xs); color: var(--color-text-muted); margin-bottom: 4px; }
.example-text { font-size: var(--font-size-base); font-style: italic; color: var(--color-text-secondary); }

.word-source {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin: 8px 0;
}

.study-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin-top: 28px;
}

/* ── Quiz questions ───────────────────── */

.quiz-question { text-align: center; }

.quiz-type {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-bottom: 14px;
  text-transform: uppercase;
  letter-spacing: 1.5px;
}

.quiz-prompt {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: 16px;
}

.quiz-phonetic {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: 14px;
}

.quiz-options {
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-width: 440px;
  margin: 0 auto;
}

.quiz-option-btn {
  padding: 14px 18px;
  border: 1.5px solid var(--color-border-light);
  border-radius: var(--radius-sm);
  background: var(--color-card);
  font-size: var(--font-size-base);
  cursor: pointer;
  transition: all .2s;
  text-align: left;
  font-family: var(--font-body);
  color: var(--color-text);
}
.quiz-option-btn:hover {
  border-color: var(--color-accent);
  background: var(--color-accent-soft);
}

.quiz-input {
  width: 100%;
  max-width: 320px;
  padding: 12px 16px;
  border: 1.5px solid var(--color-border-light);
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: var(--font-size-md);
  text-align: center;
  margin: 10px 0;
  background: var(--color-bg);
  color: var(--color-text);
}
.quiz-input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(80,176,240,.15);
}

/* ── Form inputs (modals, edit dialogs) ───── */
.form-group {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.form-label {
  display: flex;
  flex-direction: column;
  gap: 4px;
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  font-family: var(--font-body);
}
.form-input {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--color-border-light);
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: var(--font-size-base);
  text-align: left;
  background: var(--color-bg);
  color: var(--color-text);
  margin: 0;
  transition: border-color .2s;
}
.form-input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(80,176,240,.15);
}
.form-input.word-spelling-input {
  font-family: var(--font-word);
}
.modal h3 {
  font-family: var(--font-body);
  font-size: var(--font-size-lg);
  color: var(--color-text);
  margin-bottom: 4px;
}
.modal .form-actions {
  margin-top: 20px;
  display: flex;
  gap: 10px;
  justify-content: flex-end;
}

.fill-blank-sentence {
  font-size: var(--font-size-md);
  margin: 14px 0;
  padding: 14px;
  background: rgba(255,255,255,.03);
  border-radius: var(--radius-sm);
  font-style: italic;
  color: var(--color-text-secondary);
}

/* Quiz result */
.quiz-result { text-align: center; padding: 24px; }
.result-icon { font-size: 48px; margin-bottom: 12px; }
.result-text { font-size: var(--font-size-lg); font-weight: 700; margin-bottom: 10px; }
.result-detail { font-size: var(--font-size-sm); color: var(--color-text-muted); margin-bottom: 18px; }

/* ── Word bank ────────────────────────── */

.word-item { transition: box-shadow .2s; }
.word-item:hover { box-shadow: var(--shadow-md); border-color: var(--color-border-light); }

/* ── Stubborn words ───────────────────── */

.stubborn-list { display: flex; flex-direction: column; gap: 12px; }
.stubborn-word-card .word-row {
  display: flex; gap: 12px; align-items: center; flex-wrap: wrap; margin-bottom: 8px;
}
.fail-badge {
  background: var(--color-danger-soft);
  color: var(--color-danger);
  padding: 2px 10px;
  border-radius: 10px;
  font-size: 12px;
  font-weight: 600;
}

/* ── Links ────────────────────────────── */

a { color: var(--color-accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ── Toast ────────────────────────────── */

#report-toast { transition: opacity .3s; }

/* ── Bottom nav (mobile only) ─────────── */

#bottom-nav {
  display: none;
  position: fixed;
  bottom: 0; left: 0; right: 0;
  background: var(--color-card);
  border-top: 1px solid var(--color-border);
  padding: 6px 8px max(6px, env(safe-area-inset-bottom));
  z-index: 50;
  justify-content: space-around;
}

#bottom-nav a {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  text-decoration: none;
  color: var(--color-text-muted);
  font-size: 11px;
  padding: 4px 8px;
  border-radius: 8px;
  transition: all .15s;
  min-width: 56px;
}

#bottom-nav a span { font-size: 10px; }

#bottom-nav a.active {
  color: var(--color-primary);
  background: var(--color-primary-soft);
}

/* ── Add word FAB ─────────────────────── */

.fab-add {
  position: fixed;
  bottom: 80px;
  right: 20px;
  width: 52px; height: 52px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  border: none;
  font-size: 26px;
  cursor: pointer;
  z-index: 40;
  box-shadow: 0 4px 16px rgba(240,80,80,.4);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all .2s;
}
.fab-add:hover { transform: scale(1.08); }
.fab-add:active { transform: scale(.95); }

/* ── Responsive ───────────────────────── */

@media (max-width: 600px) {
  #app { padding: 10px 8px 20px; padding-bottom: 80px; }
  .logo { font-size: 20px; }

  /* Collapse header nav to a compact scrollable row */
  header { padding: 10px 0 8px; gap: 8px; margin-bottom: 16px; }
  #main-nav { gap: 0; }
  #main-nav a { font-size: 14px; padding: 5px 10px; }

  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 8px; }
  .stat-card { padding: 14px 10px; }
  .stat-card .number { font-size: 26px; }

  .card { padding: 16px 18px; margin-bottom: 10px; }

  /* Study card */
  .study-card { padding: 22px 16px !important; }
  .word-spelling { font-size: 32px; }
  .word-meaning { padding: 14px 16px; }
  .meaning-text { font-size: 18px; }

  /* Quiz */
  .quiz-options { max-width: 100%; }
  .quiz-prompt { font-size: 16px; }
  .quiz-option-btn { padding: 14px 16px; font-size: 15px; }
  .quiz-input { font-size: 18px; }

  .page-header h2 { font-size: 19px; }

  /* Buttons */
  .btn { padding: 10px 18px; font-size: 14px; }

  /* Show bottom nav, hide footer on mobile */
  #bottom-nav { display: flex; }
  footer { display: none; }
}