:root {
  --bg: #0b1120;
  --bg-2: #08101f;
  --panel: #111827;
  --panel-2: #182235;
  --text: #e5eefc;
  --muted: #94a3b8;
  --accent: #38bdf8;
  --accent-2: #22c55e;
  --danger: #fb7185;
  --border: rgba(148, 163, 184, 0.18);
  --shadow: 0 20px 45px rgba(0, 0, 0, 0.28);
}

:root[data-theme='medium'] {
  --bg: #172033;
  --bg-2: #111827;
  --panel: #1b263a;
  --panel-2: #24324a;
  --text: #eef4ff;
  --muted: #b4c0d3;
  --border: rgba(187, 200, 220, 0.22);
}

:root[data-theme='day'] {
  --bg: #eef4fb;
  --bg-2: #dfeaf7;
  --panel: rgba(255,255,255,.95);
  --panel-2: #ffffff;
  --text: #10233a;
  --muted: #5b718a;
  --border: rgba(71, 85, 105, 0.16);
  --shadow: 0 12px 30px rgba(15, 23, 42, 0.08);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; background: linear-gradient(180deg, var(--bg-2) 0%, var(--bg) 100%); color: var(--text); font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; }
a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; }
body { min-height: 100vh; }
.main-shell { max-width: 1180px; margin: 0 auto; padding: 24px 18px 60px; }
.navbar { display: flex; flex-wrap: wrap; gap: 12px; justify-content: space-between; align-items: center; margin-bottom: 24px; }
.nav-links { display: flex; flex-wrap: wrap; gap: 10px; }
.nav-link { padding: 10px 14px; border-radius: 999px; background: rgba(255,255,255,0.05); border: 1px solid var(--border); }
.hero, .panel, .card-panel, .metric-card, .dictionary-card, .plan-box, .word-card, .example-card { background: color-mix(in srgb, var(--panel) 88%, transparent); backdrop-filter: blur(10px); border: 1px solid var(--border); border-radius: 22px; box-shadow: var(--shadow); }
.hero { padding: 24px; margin-bottom: 20px; }
.hero h1 { margin: 0 0 8px; font-size: clamp(1.8rem, 4vw, 2.7rem); }
.hero p { margin: 0; color: var(--muted); }
.grid-2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 18px; }
.grid-4 { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 18px; }
.compact-grid { grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); }
.metric-card { padding: 20px; }
.metric-card h3 { margin: 0 0 6px; font-size: 1rem; color: var(--muted); }
.metric-big { margin: 0; font-size: 2.1rem; font-weight: 800; }
.mini-metric .metric-big { font-size: 1.4rem; }
.panel { padding: 20px; }
.plan-box { padding: 20px; }
.plan-box ul, .memory-list { margin: 10px 0 0; padding-left: 18px; color: var(--muted); }
.input-row { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; margin-top: 16px; }
select, input[type="text"], input[type="search"], input[type="number"] { width: 100%; padding: 14px 16px; border-radius: 14px; border: 1px solid var(--border); background: var(--panel-2); color: var(--text); }
textarea { width: 100%; padding: 14px 16px; border-radius: 16px; border: 1px solid var(--border); background: var(--panel-2); color: var(--text); min-height: 72px; resize: vertical; }
.btn-row { display: flex; flex-wrap: wrap; gap: 10px; }
.primary-btn, .secondary-btn, .ghost-btn, .score-btn { border: none; cursor: pointer; padding: 12px 16px; border-radius: 14px; transition: transform .15s ease, opacity .15s ease; }
.primary-btn:hover, .secondary-btn:hover, .ghost-btn:hover, .score-btn:hover { transform: translateY(-1px); }
.primary-btn { background: linear-gradient(135deg, #0ea5e9, #22c55e); color: white; }
.secondary-btn { background: rgba(255,255,255,0.08); color: var(--text); border: 1px solid var(--border); }
.ghost-btn { background: transparent; color: var(--text); border: 1px solid var(--border); }
.ghost-btn:disabled { opacity: .45; cursor: default; }
.score-btn { background: rgba(56, 189, 248, 0.16); color: #dff7ff; border: 1px solid rgba(56, 189, 248, 0.28); }
.score-btn.again { background: rgba(239, 68, 68, 0.18); border-color: rgba(239, 68, 68, 0.35); color: #ffd7d7; }
.score-btn.hard { background: rgba(245, 158, 11, 0.18); border-color: rgba(245, 158, 11, 0.35); color: #ffe8bf; }
.score-btn.good { background: rgba(34, 197, 94, 0.18); border-color: rgba(34, 197, 94, 0.35); color: #d8ffe6; }
.score-btn.easy { background: rgba(59, 130, 246, 0.18); border-color: rgba(59, 130, 246, 0.35); color: #dbeafe; }
.score-btn.compact, .mini-btn { padding: 8px 12px; font-size: 0.92rem; min-width: 70px; }
.study-layout { display: grid; grid-template-columns: minmax(0, 1.35fr) minmax(280px, 0.85fr); gap: 18px; align-items: start; }
.card-panel { padding: 20px; }
.progress-shell { width: 100%; height: 10px; background: rgba(255,255,255,0.08); border-radius: 999px; overflow: hidden; margin-bottom: 14px; }
.progress-bar { height: 100%; background: linear-gradient(90deg, #38bdf8, #22c55e); width: 0%; }
.flip-card { padding: 18px; border-radius: 18px; background: linear-gradient(180deg, rgba(255,255,255,0.03), rgba(255,255,255,0.01)); border: 1px solid var(--border); }
.flip-card h2 { margin: 0 0 12px; font-size: 1.5rem; }
.answer-block { margin-top: 16px; padding: 16px; border-radius: 16px; background: color-mix(in srgb, var(--panel-2) 82%, transparent); border: 1px solid var(--border); min-height: 120px; }
.answer-chinese { font-size: 1.75rem; margin: 0 0 6px; }
.answer-pinyin, .answer-sound, .answer-structure { margin: 6px 0; }
.meta-pills { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }
.pill { padding: 8px 12px; border-radius: 999px; background: rgba(255,255,255,0.06); color: var(--muted); }
.forgotten-pill { color: #fef3c7; background: rgba(245, 158, 11, 0.18); }
.score-wrap { margin-top: 12px; }
.score-wrap .btn-row { justify-content: flex-start; }
.sidebar-stack { display: grid; gap: 18px; }
.hidden { display: none; }
.word-card { padding: 16px; margin-top: 12px; }
.word-card-top { display: flex; flex-wrap: wrap; gap: 12px; justify-content: space-between; align-items: start; }
.word-card h4 { margin: 0 0 6px; }
.example-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 10px; margin-top: 12px; }
.example-card, .single-example-card { padding: 12px; }
.single-example-card .example-line + .example-line { border-top: 1px solid var(--border); padding-top: 10px; margin-top: 10px; }
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; }
th, td { padding: 10px 8px; border-bottom: 1px solid var(--border); text-align: left; vertical-align: top; }
.muted { color: var(--muted); }
.dictionary-card { padding: 18px; margin-bottom: 14px; }
.dictionary-topline { display:flex; justify-content:space-between; align-items:flex-start; gap:12px; }
.empty-state { padding: 30px; text-align: center; color: var(--muted); }
.small-note { font-size: 0.92rem; color: var(--muted); }
.section-title { margin: 0 0 14px; }
.file-input { display: inline-flex; align-items: center; gap: 10px; }
.listen-card { padding: 30px; text-align: center; }
.listen-layout { align-items: start; }
.listen-list { display:grid; gap:10px; max-height: 70vh; overflow:auto; }
.listen-list-item { display:flex; flex-direction:column; gap:4px; text-align:left; width:100%; padding:12px 14px; border-radius:14px; border:1px solid var(--border); background:var(--panel-2); color:var(--text); cursor:pointer; }
.listen-list-item.active { border-color: rgba(56, 189, 248, 0.6); }
.footer-gap { height: 20px; }

@media (max-width: 840px) { .study-layout { grid-template-columns: 1fr; } }

.study-top-row { display:flex; gap:16px; align-items:center; }
.study-top-row .progress-shell { flex:1; margin-bottom:0; }
.compact-nav-row { flex-shrink:0; }
.compact-nav { padding: 10px 14px; }
.compact-nav:disabled { opacity: .4; cursor: default; transform: none; }
.hint-block { margin: 0 0 12px; padding: 12px 14px; border-radius: 14px; background: rgba(56, 189, 248, 0.08); border: 1px solid rgba(56, 189, 248, 0.20); }
.hint-pill-label { font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--accent); margin-bottom: 4px; }
.hint-pill-value { color: var(--text); }
.controls-row { align-items: center; }
.word-type-line { color: var(--muted); }
.type-pill { display:inline-block; margin-right:8px; padding:4px 8px; border-radius:999px; color: var(--text); font-size: .8rem; border:1px solid transparent; }
.type-default { background: rgba(148, 163, 184, 0.14); border-color: rgba(148, 163, 184, 0.26); }
.type-pronoun { background: rgba(59,130,246,.18); border-color: rgba(59,130,246,.38); }
.type-verb { background: rgba(34,197,94,.18); border-color: rgba(34,197,94,.38); }
.type-adjective { background: rgba(168,85,247,.18); border-color: rgba(168,85,247,.38); }
.type-adverb { background: rgba(234,88,12,.18); border-color: rgba(234,88,12,.38); }
.type-noun { background: rgba(14,165,233,.18); border-color: rgba(14,165,233,.38); }
.type-connector { background: rgba(250,204,21,.18); border-color: rgba(250,204,21,.38); }
.type-particle { background: rgba(244,114,182,.18); border-color: rgba(244,114,182,.38); }
.type-phrase { background: rgba(20,184,166,.18); border-color: rgba(20,184,166,.38); }
.type-time { background: rgba(99,102,241,.18); border-color: rgba(99,102,241,.38); }
.type-question { background: rgba(239,68,68,.18); border-color: rgba(239,68,68,.38); }
.example-chinese { font-size: 1.05rem; margin: 0 0 8px; }
.example-pinyin { margin: 0 0 8px; color: #dbeafe; }
.stacked-mini-buttons { justify-content:flex-end; }
.checkbox-row { display:flex; gap:10px; align-items:center; margin-top:16px; }
.settings-panel { max-width: 820px; margin: 0 auto; }
.history-panel { margin-top: 20px; text-align:left; }
.completion-panel { color: var(--text); }