/* ===========================================================
   東大英単語2400 — Apple-like Glassmorphism Design System
=========================================================== */

:root{
  --bg-0:#FBFBFD;
  --bg-1:#F2F3F6;
  --bg-2:#E9ECF1;
  --glass-bg: rgba(255,255,255,0.6);
  --glass-bg-strong: rgba(255,255,255,0.72);
  --glass-border: rgba(255,255,255,0.35);
  --glass-blur: 20px;
  --ink-1:#1D1D1F;
  --ink-2:#3A3A3E;
  --ink-3:#6E6E73;
  --ink-4:#8A8A8E;
  --accent:#0A84FF;
  --accent-2:#5E5CE6;
  --accent-grad: linear-gradient(135deg,#0A84FF 0%, #5E5CE6 100%);
  --success:#30D158;
  --success-grad: linear-gradient(135deg,#34C759 0%, #30D158 100%);
  --danger:#FF453A;
  --danger-grad: linear-gradient(135deg,#FF6961 0%, #FF453A 100%);
  --warn:#FF9F0A;
  --radius-lg:28px;
  --radius-md:20px;
  --radius-sm:14px;
  --shadow-soft: 0 8px 30px rgba(0,0,0,0.06), 0 2px 8px rgba(0,0,0,0.04);
  --shadow-strong: 0 20px 60px rgba(0,0,0,0.14), 0 6px 20px rgba(0,0,0,0.08);
  --header-h: 64px;
  --nav-h: 84px;
  --safe-bottom: env(safe-area-inset-bottom, 0px);
}

*{ box-sizing:border-box; -webkit-tap-highlight-color: transparent; }
html,body{
  margin:0; padding:0; height:100%;
  font-family:'Inter','Noto Sans JP',-apple-system,BlinkMacSystemFont,"Hiragino Sans","Yu Gothic",sans-serif;
  color:var(--ink-1);
  background: radial-gradient(circle at 15% 0%, #F5F7FF 0%, var(--bg-0) 45%, var(--bg-1) 100%);
  background-attachment: fixed;
  -webkit-font-smoothing:antialiased;
  overscroll-behavior:none;
}
button{ font-family:inherit; }
input,select{ font-family:inherit; }
::selection{ background: rgba(10,132,255,0.2); }

/* ---------- Loading ---------- */
.app-loading{
  position:fixed; inset:0; z-index:999;
  display:flex; flex-direction:column; align-items:center; justify-content:center; gap:20px;
  background:var(--bg-0); transition:opacity .5s ease, visibility .5s ease;
}
.app-loading.hide{ opacity:0; visibility:hidden; pointer-events:none; }
.loading-orb{
  width:56px; height:56px; border-radius:50%;
  background:var(--accent-grad);
  box-shadow: 0 0 40px rgba(10,132,255,0.35);
  animation: pulse 1.4s ease-in-out infinite;
}
@keyframes pulse{ 0%,100%{ transform:scale(0.85); opacity:.7;} 50%{ transform:scale(1.05); opacity:1;} }
.app-loading p{ color:var(--ink-3); font-size:14px; letter-spacing:.02em; }

/* ---------- Glass panel base ---------- */
.glass-panel{
  background: var(--glass-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(160%);
  backdrop-filter: blur(var(--glass-blur)) saturate(160%);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
}

/* ---------- Header ---------- */
.app-header{
  position:fixed; top:0; left:0; right:0; z-index:60;
  height:var(--header-h);
  background: rgba(251,251,253,0.72);
  -webkit-backdrop-filter: blur(24px) saturate(180%);
  backdrop-filter: blur(24px) saturate(180%);
  border-bottom:1px solid rgba(0,0,0,0.06);
  display:flex; align-items:center;
}
.header-inner{
  width:100%; max-width:900px; margin:0 auto;
  display:flex; align-items:center; justify-content:space-between;
  padding:0 20px;
}
.app-title{
  font-size:19px; font-weight:700; letter-spacing:-0.01em; margin:0;
  color:var(--ink-1);
}
.title-accent{
  background:var(--accent-grad);
  -webkit-background-clip:text; background-clip:text; color:transparent;
  font-weight:800;
}
.icon-btn{
  width:38px; height:38px; border-radius:50%;
  border:1px solid rgba(0,0,0,0.06);
  background:rgba(255,255,255,0.5);
  color:var(--ink-2);
  display:flex; align-items:center; justify-content:center;
  cursor:pointer; transition: transform .15s ease, background .2s ease;
}
.icon-btn:hover{ background:rgba(255,255,255,0.85); }
.icon-btn:active{ transform:scale(0.9); }

/* ---------- Main layout ---------- */
.app-main{
  padding-top: calc(var(--header-h) + 10px);
  padding-bottom: calc(var(--nav-h) + var(--safe-bottom) + 16px);
  min-height:100vh;
  max-width:900px; margin:0 auto;
}
.view{ padding:0 16px; animation: fadeIn .35s ease; }
@keyframes fadeIn{ from{opacity:0; transform:translateY(6px);} to{opacity:1; transform:none;} }

/* ===========================================================
   ① LIST VIEW
=========================================================== */
.list-toolbar{
  position:sticky; top:calc(var(--header-h) + 6px); z-index:30;
  padding:16px 18px; margin-bottom:14px;
  display:flex; flex-direction:column; gap:12px;
}
.search-bar{
  display:flex; align-items:center; gap:10px;
  background:rgba(255,255,255,0.55);
  border:1px solid rgba(0,0,0,0.05);
  border-radius:14px; padding:10px 14px;
}
.search-icon{ color:var(--ink-4); font-size:14px; }
#search-input{
  flex:1; border:none; background:transparent; outline:none;
  font-size:16px; color:var(--ink-1);
}
#search-input::placeholder{ color:var(--ink-4); }
.search-clear{
  border:none; background:none; color:var(--ink-4); cursor:pointer;
  display:none; font-size:15px; padding:2px;
}
.search-bar.has-text .search-clear{ display:block; }

.toolbar-row{ display:flex; align-items:center; justify-content:space-between; gap:10px; flex-wrap:wrap; }
.filter-chips{ display:flex; gap:6px; flex-wrap:wrap; }
.chip{
  border:1px solid rgba(0,0,0,0.06);
  background:rgba(255,255,255,0.5);
  color:var(--ink-2);
  border-radius:999px; padding:6px 14px; font-size:13px; font-weight:500;
  cursor:pointer; transition: all .18s ease;
}
.chip.active{
  background:var(--accent-grad); color:#fff; border-color:transparent;
  box-shadow:0 4px 14px rgba(10,132,255,0.3);
}
.toggle-group{ display:flex; gap:16px; flex-wrap:wrap; }
.switch-label{ display:flex; align-items:center; gap:8px; font-size:13px; color:var(--ink-2); font-weight:500; }
.switch{ position:relative; display:inline-block; width:44px; height:26px; }
.switch input{ opacity:0; width:0; height:0; position:absolute; }
.switch-track{
  position:absolute; inset:0; border-radius:999px;
  background:rgba(120,120,128,0.24); transition:.25s;
  display:block;
}
.switch-thumb{
  position:absolute; top:2px; left:2px; width:22px; height:22px; border-radius:50%;
  background:#fff; box-shadow:0 2px 4px rgba(0,0,0,0.2); transition:.25s;
}
.switch input:checked + .switch-track{ background:var(--accent-grad); }
.switch input:checked + .switch-track .switch-thumb{ transform:translateX(18px); }

.list-count{ font-size:12px; color:var(--ink-4); font-weight:500; }

.list-shell{ position:relative; }
.list-scroll{
  height: calc(100vh - var(--header-h) - var(--nav-h) - 190px);
  min-height: 380px;
  overflow-y:auto; overflow-x:hidden;
  -webkit-overflow-scrolling: touch;
  padding-right:26px;
  scrollbar-width: thin;
}
.list-spacer{ position:relative; }
.list-rows{ position:absolute; top:0; left:0; right:0; }

.word-row{
  display:flex; align-items:center; gap:12px;
  padding:14px 16px;
  margin:0 0 8px 0;
  background:rgba(255,255,255,0.55);
  border:1px solid rgba(255,255,255,0.4);
  border-radius:var(--radius-md);
  box-shadow: 0 2px 10px rgba(0,0,0,0.03);
  cursor:pointer;
  transition: background .2s ease, box-shadow .2s ease;
}
.word-row:hover{ background:rgba(255,255,255,0.75); }
.word-row.selected{
  background: linear-gradient(135deg, rgba(10,132,255,0.10), rgba(94,92,230,0.10));
  border-color: rgba(10,132,255,0.25);
  box-shadow: 0 4px 18px rgba(10,132,255,0.12);
}
.word-row-index{ font-size:11px; color:var(--ink-4); width:34px; flex-shrink:0; font-weight:600; }
.word-row-main{ flex:1; min-width:0; }
.word-row-head{ display:flex; align-items:baseline; gap:10px; flex-wrap:wrap; }
.word-row-en{ font-size:17px; font-weight:700; color:var(--ink-1); letter-spacing:-0.01em; }
.word-row-speak{
  border:none; background:none; color:var(--ink-4); cursor:pointer; font-size:13px;
  padding:2px 4px; flex-shrink:0;
}
.word-row-speak:hover{ color:var(--accent); }
.word-row-ja{
  font-size:13.5px; color:var(--ink-3); margin-top:3px; line-height:1.5;
  transition: filter .2s ease, opacity .2s ease;
}
.word-row-ja.masked{ filter:blur(6px); opacity:.7; user-select:none; }
.word-row-example{
  margin-top:8px; padding-top:8px; border-top:1px dashed rgba(0,0,0,0.08);
  font-size:12.5px; color:var(--ink-3); display:none; line-height:1.6;
}
.word-row.expanded .word-row-example{ display:block; }
.word-row-actions{ display:flex; gap:6px; flex-shrink:0; }
.row-action-btn{
  width:34px; height:34px; border-radius:50%;
  border:1px solid rgba(0,0,0,0.06); background:rgba(255,255,255,0.6);
  color:var(--ink-4); cursor:pointer; font-size:13px;
  display:flex; align-items:center; justify-content:center;
  transition: all .18s ease;
}
.row-action-btn.learned.active{ background:var(--success-grad); color:#fff; border-color:transparent; }
.row-action-btn.difficult.active{ background:var(--danger-grad); color:#fff; border-color:transparent; }
.row-action-btn:hover{ transform:scale(1.08); }
.status-dot{
  width:8px; height:8px; border-radius:50%; flex-shrink:0; margin-right:2px;
}
.status-dot.learned{ background:var(--success); }
.status-dot.difficult{ background:var(--danger); }
.status-dot.new{ background:transparent; }

.list-empty-msg{
  text-align:center; color:var(--ink-4); padding:60px 20px; font-size:14px;
}

/* A-Z jump bar */
.az-bar{
  position:absolute; top:0; right:0; bottom:0; width:22px;
  display:flex; flex-direction:column; align-items:center; justify-content:center;
  gap:1px; padding:8px 0; user-select:none;
  border-radius:12px;
}
.az-bar span{
  font-size:9.5px; color:var(--ink-4); font-weight:700; cursor:pointer;
  width:100%; text-align:center; line-height:1.5;
}
.az-bar span:hover, .az-bar span.active{ color:var(--accent); }

/* ===========================================================
   ② CARD VIEW
=========================================================== */
.view-card{ display:flex; flex-direction:column; height: calc(100vh - var(--header-h) - var(--nav-h) - 6px); }
.card-header{
  display:flex; align-items:center; justify-content:space-between;
  padding:12px 18px; margin-bottom:12px;
}
.card-progress-text{ font-weight:700; color:var(--ink-2); font-size:14px; }
.card-pool-select select{
  border:none; background:rgba(255,255,255,0.6); border-radius:10px;
  padding:6px 10px; font-size:13px; color:var(--ink-2); font-weight:500;
}
.card-stage{
  flex:1; position:relative; display:flex; align-items:center; justify-content:center;
  perspective:1600px; min-height:340px;
}
.card-empty{ text-align:center; color:var(--ink-4); }
.card-empty i{ font-size:40px; margin-bottom:10px; color:var(--ink-4); }

.flash-card{
  position:absolute; width:min(92%, 380px); height:min(56vh, 460px);
  border-radius:32px; cursor:grab;
  transform-style:preserve-3d;
  transition: transform .45s cubic-bezier(.22,1,.36,1), opacity .3s ease;
  will-change:transform;
}
.flash-card.dragging{ transition:none; cursor:grabbing; }
.flash-card.flipped .card-face-inner{ transform:rotateY(180deg); }
.card-face-inner{
  position:relative; width:100%; height:100%;
  transition: transform .5s cubic-bezier(.4,0.2,0.2,1);
  transform-style:preserve-3d;
}
.card-face{
  position:absolute; inset:0; border-radius:32px;
  backface-visibility:hidden;
  background: var(--glass-bg-strong);
  -webkit-backdrop-filter: blur(24px) saturate(180%);
  backdrop-filter: blur(24px) saturate(180%);
  border:1px solid rgba(255,255,255,0.5);
  box-shadow: var(--shadow-strong);
  display:flex; flex-direction:column; align-items:center; justify-content:center;
  padding:36px 28px; text-align:center; gap:14px;
}
.card-face-back{ transform:rotateY(180deg); overflow-y:auto; justify-content:flex-start; padding-top:44px; }
.card-face-index{ position:absolute; top:20px; left:24px; font-size:12px; color:var(--ink-4); font-weight:700; }
.card-face-en{ font-size:34px; font-weight:800; color:var(--ink-1); letter-spacing:-0.02em; }
.card-face-hint{ font-size:13px; color:var(--ink-4); margin-top:6px; }
.card-face-tap-hint{ position:absolute; bottom:22px; font-size:11px; color:var(--ink-4); display:flex; align-items:center; gap:6px; }
.card-face-ja{ font-size:19px; font-weight:700; color:var(--ink-1); line-height:1.6; }
.card-face-ja-en{ font-size:15px; color:var(--ink-3); font-weight:600; margin-bottom:4px; }
.card-status-badge{
  position:absolute; top:18px; right:20px; font-size:11px; font-weight:700;
  padding:4px 10px; border-radius:999px;
}
.card-status-badge.learned{ background:rgba(48,209,88,0.15); color:#1e9a41; }
.card-status-badge.difficult{ background:rgba(255,69,58,0.13); color:#d9291f; }

.card-swipe-hint-left, .card-swipe-hint-right{
  position:absolute; top:50%; transform:translateY(-50%);
  font-size:15px; font-weight:800; padding:8px 16px; border-radius:12px;
  opacity:0; transition:opacity .1s ease;
}
.card-swipe-hint-left{ left:24px; background:rgba(255,69,58,0.15); color:#d9291f; }
.card-swipe-hint-right{ right:24px; background:rgba(48,209,88,0.18); color:#1e9a41; }

.card-controls{
  display:flex; align-items:center; justify-content:center; gap:22px;
  padding:18px 0 6px;
}
.round-btn{
  border:none; border-radius:999px; cursor:pointer;
  display:flex; align-items:center; gap:8px;
  padding:14px 22px; font-size:14px; font-weight:700;
  box-shadow: var(--shadow-soft);
  transition: transform .15s ease;
  color:#fff;
}
.round-btn:active{ transform:scale(0.92); }
.round-btn.danger{ background:var(--danger-grad); }
.round-btn.success{ background:var(--success-grad); }
.round-btn.ghost{
  background:rgba(255,255,255,0.6); color:var(--ink-2); border:1px solid rgba(0,0,0,0.06);
  padding:14px 16px;
}

/* ===========================================================
   ③ QUIZ VIEW
=========================================================== */
.quiz-setup{ padding:34px 26px; text-align:center; margin-top:20px; }
.quiz-setup h2{ margin:0 0 6px; font-size:22px; font-weight:800; }
.quiz-desc{ color:var(--ink-3); font-size:13.5px; margin-bottom:22px; }
.quiz-options{ display:flex; gap:14px; justify-content:center; flex-wrap:wrap; margin-bottom:26px; }
.quiz-options label{ display:flex; flex-direction:column; gap:6px; font-size:12.5px; color:var(--ink-3); font-weight:600; }
.quiz-options select{
  border:none; background:rgba(255,255,255,0.65); border-radius:12px; padding:10px 14px;
  font-size:14px; color:var(--ink-1); font-weight:600; min-width:150px;
}
.primary-btn{
  border:none; background:var(--accent-grad); color:#fff; font-weight:700; font-size:15px;
  padding:14px 28px; border-radius:16px; cursor:pointer;
  box-shadow:0 8px 24px rgba(10,132,255,0.3);
  display:inline-flex; align-items:center; gap:8px;
  transition: transform .15s ease;
}
.primary-btn:active{ transform:scale(0.96); }
.ghost-btn{
  border:1px solid rgba(0,0,0,0.08); background:rgba(255,255,255,0.5); color:var(--ink-2);
  font-weight:600; font-size:14px; padding:13px 22px; border-radius:16px; cursor:pointer;
}
.danger-btn{
  border:none; background:rgba(255,69,58,0.12); color:#d9291f; font-weight:700; font-size:14px;
  padding:13px 22px; border-radius:16px; cursor:pointer;
}

.quiz-play{ margin-top:16px; }
.quiz-top{ padding:14px 18px; margin-bottom:20px; }
.quiz-progress-bar{ height:6px; background:rgba(0,0,0,0.06); border-radius:999px; overflow:hidden; }
.quiz-progress-fill{ height:100%; background:var(--accent-grad); width:0%; transition: width .3s ease; }
.quiz-meta{ display:flex; justify-content:space-between; margin-top:8px; font-size:12.5px; color:var(--ink-3); font-weight:600; }

.quiz-question-area{ display:flex; justify-content:center; margin-bottom:24px; }
.quiz-question-card{
  width:100%; max-width:420px; padding:40px 26px; border-radius:28px; text-align:center;
  background:var(--glass-bg-strong);
  -webkit-backdrop-filter: blur(24px) saturate(180%);
  backdrop-filter: blur(24px) saturate(180%);
  border:1px solid rgba(255,255,255,0.5);
  box-shadow: var(--shadow-strong);
  transition: transform .12s ease;
}
.quiz-question-card.shake{ animation: shake .4s ease; }
.quiz-question-card.flash-correct{ box-shadow: 0 0 0 4px rgba(48,209,88,0.5), var(--shadow-strong); }
@keyframes shake{
  0%,100%{ transform:translateX(0); }
  20%{ transform:translateX(-10px); }
  40%{ transform:translateX(8px); }
  60%{ transform:translateX(-6px); }
  80%{ transform:translateX(4px); }
}
.quiz-question-type{ font-size:12px; font-weight:700; color:var(--accent); text-transform:uppercase; letter-spacing:.06em; margin-bottom:14px; }
.quiz-question-word{ font-size:30px; font-weight:800; color:var(--ink-1); letter-spacing:-0.01em; line-height:1.4; }

.quiz-choices{ display:grid; grid-template-columns:1fr 1fr; gap:12px; max-width:520px; margin:0 auto; }
.quiz-choice-btn{
  border:1px solid rgba(0,0,0,0.06); background:rgba(255,255,255,0.6);
  border-radius:16px; padding:18px 14px; font-size:14.5px; font-weight:600; color:var(--ink-1);
  cursor:pointer; transition: all .15s ease; text-align:center; line-height:1.4;
}
.quiz-choice-btn:hover{ background:rgba(255,255,255,0.85); }
.quiz-choice-btn:active{ transform:scale(0.97); }
.quiz-choice-btn.correct{ background:var(--success-grad); color:#fff; border-color:transparent; }
.quiz-choice-btn.wrong{ background:var(--danger-grad); color:#fff; border-color:transparent; }
.quiz-choice-btn.disabled{ pointer-events:none; opacity:.55; }

.quiz-result{ margin-top:40px; padding:40px 26px; text-align:center; display:flex; flex-direction:column; align-items:center; gap:16px; }
.result-ring-wrap{ position:relative; width:150px; height:150px; }
.result-ring{ width:150px; height:150px; transform:rotate(-90deg); }
.ring-bg{ fill:none; stroke:rgba(0,0,0,0.07); stroke-width:12; }
.ring-fg{ fill:none; stroke-width:12; stroke-linecap:round; transition: stroke-dasharray 1s ease; }
#result-ring-fg{ stroke:url(#none); stroke:var(--accent); }
.result-ring-label{
  position:absolute; inset:0; display:flex; flex-direction:column; align-items:center; justify-content:center;
}
.result-ring-label span{ font-size:28px; font-weight:800; color:var(--ink-1); }
.result-ring-label small{ font-size:11px; color:var(--ink-4); font-weight:600; }
#result-summary{ color:var(--ink-3); font-weight:600; font-size:14px; }
.result-actions{ display:flex; gap:12px; }

/* ===========================================================
   ④ STATS VIEW
=========================================================== */
.stats-grid{
  display:grid; grid-template-columns:repeat(2, 1fr); gap:14px; margin-top:14px;
}
.stat-card{ padding:22px; }
.stat-card h3{ font-size:14px; font-weight:700; margin:0 0 14px; display:flex; align-items:center; gap:8px; color:var(--ink-2); }
.stat-card h3 i{ color:var(--accent); }
.stat-card-wide{ grid-column:1 / -1; }
.stat-card-ring{ display:flex; flex-direction:column; align-items:center; justify-content:center; position:relative; }
.progress-ring{ width:160px; height:160px; transform:rotate(-90deg); }
#stats-ring-fg{ stroke:var(--accent); }
.progress-ring-label{ position:absolute; top:44%; left:50%; transform:translate(-50%,-50%); text-align:center; }
.progress-ring-label span{ font-size:30px; font-weight:800; color:var(--ink-1); }
.progress-ring-label small{ font-size:12px; color:var(--ink-4); font-weight:600; }
.stat-caption{ margin:10px 0 0; font-size:12.5px; color:var(--ink-3); font-weight:600; }

.level-bars{ display:flex; flex-direction:column; gap:12px; }
.level-bar-row{ display:flex; align-items:center; gap:10px; }
.level-bar-label{ font-size:11.5px; color:var(--ink-3); font-weight:700; width:64px; flex-shrink:0; }
.level-bar-track{ flex:1; height:8px; border-radius:999px; background:rgba(0,0,0,0.06); overflow:hidden; }
.level-bar-fill{ height:100%; background:var(--accent-grad); border-radius:999px; transition: width .5s ease; }
.level-bar-pct{ font-size:11px; color:var(--ink-4); font-weight:700; width:36px; text-align:right; flex-shrink:0; }

.chart-wrap{ position:relative; height:220px; }

.difficult-list{ margin:0; padding:0; list-style:none; display:flex; flex-direction:column; gap:8px; }
.difficult-list li{
  display:flex; align-items:center; justify-content:space-between; gap:10px;
  padding:10px 14px; background:rgba(255,69,58,0.06); border-radius:14px;
}
.difficult-rank{ font-size:12px; font-weight:800; color:var(--danger); width:22px; }
.difficult-word{ font-weight:700; font-size:14px; color:var(--ink-1); flex:1; }
.difficult-meaning{ font-size:12px; color:var(--ink-3); flex:2; }
.difficult-count{ font-size:11.5px; color:var(--danger); font-weight:700; flex-shrink:0; }
.stats-empty{ text-align:center; color:var(--ink-4); font-size:13px; padding:20px 0; }

.quick-summary{ display:flex; flex-direction:column; gap:10px; }
.quick-summary-row{ display:flex; justify-content:space-between; font-size:13px; color:var(--ink-2); font-weight:600; }
.quick-summary-row b{ color:var(--ink-1); font-weight:800; }

/* ===========================================================
   ⑤ SETTINGS VIEW
=========================================================== */
.settings-list{ display:flex; flex-direction:column; gap:16px; margin-top:14px; }
.settings-group{ padding:22px; }
.settings-group h3{ font-size:15px; font-weight:700; margin:0 0 14px; display:flex; align-items:center; gap:8px; color:var(--ink-2); }
.settings-group h3 i{ color:var(--accent); }
.settings-row{
  display:flex; align-items:center; justify-content:space-between; gap:14px;
  padding:12px 0; border-bottom:1px solid rgba(0,0,0,0.05); font-size:14px; color:var(--ink-2); font-weight:500;
}
.settings-row:last-of-type{ border-bottom:none; }
.settings-row input[type="range"]{ flex:1; accent-color:var(--accent); }
.settings-note{ font-size:12.5px; color:var(--ink-4); line-height:1.7; margin:0 0 14px; }
.settings-actions{ display:flex; gap:10px; flex-wrap:wrap; margin-top:6px; }
.settings-status{ font-size:12.5px; color:var(--accent); font-weight:600; min-height:16px; margin-top:10px; }

/* ===========================================================
   Bottom Navigation
=========================================================== */
.bottom-nav{
  position:fixed; bottom:14px; left:16px; right:16px; z-index:60;
  max-width:520px; margin:0 auto;
  height:var(--nav-h);
  padding-bottom: var(--safe-bottom);
  display:flex; align-items:center; justify-content:space-around;
  border-radius:26px;
}
.nav-item{
  border:none; background:none; cursor:pointer;
  display:flex; flex-direction:column; align-items:center; gap:4px;
  color:var(--ink-4); font-size:10.5px; font-weight:600;
  padding:8px 10px; border-radius:16px; flex:1;
  transition: color .2s ease;
}
.nav-item i{ font-size:19px; }
.nav-item.active{ color:var(--accent); }

/* ===========================================================
   Toast
=========================================================== */
.toast{
  position:fixed; bottom: calc(var(--nav-h) + var(--safe-bottom) + 26px); left:50%;
  transform:translateX(-50%) translateY(12px);
  background:rgba(29,29,31,0.88); color:#fff; font-size:13px; font-weight:600;
  padding:12px 20px; border-radius:14px; z-index:200;
  opacity:0; pointer-events:none; transition: all .3s ease;
  backdrop-filter: blur(10px);
  max-width:80%; text-align:center;
}
.toast.show{ opacity:1; transform:translateX(-50%) translateY(0); pointer-events:auto; }

/* ===========================================================
   Responsive
=========================================================== */
@media (max-width: 640px){
  .stats-grid{ grid-template-columns:1fr; }
  .card-face-en{ font-size:28px; }
  .quiz-question-word{ font-size:24px; }
  .quiz-choices{ grid-template-columns:1fr; }
  .app-title{ font-size:17px; }
  .list-scroll{ height: calc(100vh - var(--header-h) - var(--nav-h) - 210px); }
}

@media (min-width: 900px){
  .app-main{ max-width:900px; }
}

/* scrollbar cosmetics */
.list-scroll::-webkit-scrollbar{ width:5px; }
.list-scroll::-webkit-scrollbar-thumb{ background:rgba(0,0,0,0.12); border-radius:10px; }