:root {
  --bg: #f6f7fb;
  --bg-grad: radial-gradient(1200px 600px at 10% -10%, #e8e7ff 0%, transparent 60%),
             radial-gradient(900px 500px at 110% 0%, #dff3ff 0%, transparent 55%);
  --surface: #ffffff;
  --surface-2: #f2f3f9;
  --text: #1b1d29;
  --muted: #6b7183;
  --line: #e4e6ef;
  --primary: #4f46e5;
  --primary-1: #4338ca;
  --ok: #15803d;
  --ok-bg: #e7f8ee;
  --bad: #be123c;
  --bad-bg: #fdeaf0;
  --skip: #a16207;
  --skip-bg: #fdf3e0;
  --radius: 16px;
  --shadow: 0 10px 30px rgba(23, 26, 51, .08);
  --bar-h: 92px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1014;
    --bg-grad: radial-gradient(1200px 600px at 10% -10%, #221f4a 0%, transparent 60%),
               radial-gradient(900px 500px at 110% 0%, #10303f 0%, transparent 55%);
    --surface: #171923;
    --surface-2: #1f2230;
    --text: #e9ebf5;
    --muted: #9aa1b5;
    --line: #2a2e3d;
    --primary: #7c7bff;
    --primary-1: #6a68f5;
    --ok: #4ade80;
    --ok-bg: #12301f;
    --bad: #fb7185;
    --bad-bg: #33141d;
    --skip: #fbbf24;
    --skip-bg: #33280f;
    --shadow: 0 10px 30px rgba(0, 0, 0, .45);
  }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

html, body { height: 100%; }

body {
  margin: 0;
  background: var(--bg);
  background-image: var(--bg-grad);
  background-attachment: fixed;
  color: var(--text);
  font: 15px/1.55 -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", Roboto, sans-serif;
  -webkit-font-smoothing: antialiased;
  padding-bottom: calc(var(--bar-h) + env(safe-area-inset-bottom));
}

.app {
  width: 100%;
  max-width: 980px;
  margin: 0 auto;
  padding: 18px 16px 8px;
}

/* ---------- 顶栏 ---------- */
.topbar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 6px 2px 16px;
}

.brand { display: flex; align-items: center; gap: 12px; min-width: 0; }

.brand-dot {
  width: 12px; height: 12px; border-radius: 4px; flex: 0 0 auto;
  background: linear-gradient(135deg, var(--primary), #22d3ee);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--primary) 18%, transparent);
}

.brand-text { min-width: 0; }
.brand-text h1 { margin: 0; font-size: 19px; letter-spacing: .2px; }
.brand-text p { margin: 2px 0 0; font-size: 12.5px; color: var(--muted); }

.topbar-right { margin-left: auto; display: flex; gap: 8px; align-items: center; }

/* ---------- 按钮 ---------- */
.btn {
  appearance: none;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--text);
  border-radius: 11px;
  padding: 9px 14px;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: transform .06s ease, background .15s ease, border-color .15s ease;
  min-height: 40px;
}
.btn:hover { border-color: color-mix(in srgb, var(--primary) 45%, var(--line)); }
.btn:active { transform: translateY(1px); }
.btn:focus-visible { outline: 3px solid color-mix(in srgb, var(--primary) 45%, transparent); outline-offset: 1px; }

.btn.primary {
  background: linear-gradient(180deg, var(--primary), var(--primary-1));
  border-color: transparent;
  color: #fff;
  box-shadow: 0 6px 16px color-mix(in srgb, var(--primary) 32%, transparent);
}
.btn.ghost { background: transparent; }
.btn.danger { color: var(--bad); border-color: color-mix(in srgb, var(--bad) 35%, var(--line)); }
.btn.big { flex: 1; min-height: 52px; font-size: 16px; font-weight: 600; }
.btn.tiny { padding: 5px 9px; font-size: 12.5px; min-height: 30px; border-radius: 9px; }
.btn[disabled] { opacity: .5; cursor: not-allowed; }

.icon-btn {
  appearance: none; border: 1px solid var(--line); background: var(--surface);
  color: var(--text); width: 38px; height: 38px; border-radius: 11px;
  font-size: 17px; cursor: pointer; flex: 0 0 auto;
}
.icon-btn:hover { border-color: var(--primary); }

.btn-row { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }
.btn-row.center { justify-content: center; margin-top: 18px; }

.check-row {
  display: inline-flex; align-items: center; gap: 6px; font-size: 13px;
  color: var(--muted); cursor: pointer; user-select: none; padding: 6px 2px;
}
.check-row input { width: 16px; height: 16px; accent-color: var(--primary); cursor: pointer; }

/* ---------- 面板 / 卡片 ---------- */
.panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px;
}

.panel-head {
  display: flex; align-items: flex-start; justify-content: space-between;
  gap: 12px; flex-wrap: wrap; margin-bottom: 14px;
}
.panel-head h2 { margin: 0; font-size: 17px; }
.muted { color: var(--muted); }
.small { font-size: 12.5px; }

/* ---------- 书库列表 ---------- */
.book-list { display: grid; gap: 10px; }

.book-card {
  border: 1px solid var(--line);
  border-radius: 13px;
  padding: 14px;
  background: var(--surface-2);
  display: flex; gap: 12px; align-items: flex-start; flex-wrap: wrap;
}
.book-card .book-main { min-width: 0; flex: 1 1 260px; }
.book-card h3 { margin: 0 0 3px; font-size: 15.5px; display: flex; align-items: center; gap: 8px; }
.book-card .book-meta { font-size: 12.5px; color: var(--muted); }
.book-card .book-desc { font-size: 13px; color: var(--muted); margin: 6px 0 0; }
.book-card .book-actions { display: flex; gap: 6px; flex-wrap: wrap; }

.tag {
  font-size: 11px; padding: 2px 7px; border-radius: 999px;
  background: color-mix(in srgb, var(--primary) 14%, transparent);
  color: var(--primary); font-weight: 600; letter-spacing: .2px;
}
.tag.warn { background: var(--skip-bg); color: var(--skip); }

.empty {
  text-align: center; padding: 34px 16px; color: var(--muted);
  border: 1px dashed var(--line); border-radius: 13px;
}

/* ---------- 条目表格 ---------- */
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: 13px; }
.phrase-table { width: 100%; border-collapse: collapse; font-size: 13.5px; min-width: 640px; }
.phrase-table th, .phrase-table td {
  text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: top;
}
.phrase-table thead th { background: var(--surface-2); font-weight: 600; font-size: 12.5px; color: var(--muted); }
.phrase-table tbody tr:last-child td { border-bottom: 0; }
.phrase-table tr:hover td { background: color-mix(in srgb, var(--primary) 5%, transparent); }
.phrase-table .en-cell { font-weight: 600; }
.phrase-table .sub { color: var(--muted); font-size: 12px; display: block; margin-top: 2px; }
.col-act { width: 108px; }

/* ---------- 背诵视图 ---------- */
.study-head { margin-bottom: 14px; }

.progress-line { display: flex; align-items: center; gap: 12px; font-size: 13px; color: var(--muted); }
.progress-track {
  flex: 1; height: 7px; border-radius: 999px; background: var(--surface-2);
  border: 1px solid var(--line); overflow: hidden;
}
.progress-fill {
  height: 100%; width: 0%; border-radius: 999px;
  background: linear-gradient(90deg, var(--primary), #22d3ee);
  transition: width .25s ease;
}

.counters { display: flex; gap: 8px; margin-top: 10px; flex-wrap: wrap; }
.counter {
  font-size: 12.5px; padding: 5px 10px; border-radius: 999px;
  border: 1px solid var(--line); background: var(--surface);
}
.counter b { font-size: 13.5px; }
.counter.ok { color: var(--ok); background: var(--ok-bg); border-color: transparent; }
.counter.bad { color: var(--bad); background: var(--bad-bg); border-color: transparent; }
.counter.skip { color: var(--skip); background: var(--skip-bg); border-color: transparent; }

.mode-switch {
  display: inline-flex; gap: 4px; margin-top: 12px; padding: 4px;
  background: var(--surface-2); border-radius: 12px; border: 1px solid var(--line);
}
.mode-btn {
  appearance: none; border: 0; background: transparent; color: var(--muted);
  padding: 8px 14px; border-radius: 9px; font-size: 13.5px; cursor: pointer; font-weight: 500;
}
.mode-btn.active {
  background: var(--surface); color: var(--text); font-weight: 600;
  box-shadow: 0 2px 8px rgba(20, 22, 40, .1);
}

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

.label { margin: 0 0 8px; font-size: 12.5px; color: var(--muted); letter-spacing: .3px; }
.prompt { margin: 0 0 18px; font-weight: 700; word-break: break-word; }
.prompt.zh { font-size: 28px; line-height: 1.35; }
.prompt.en { font-size: 30px; line-height: 1.3; font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }

.input-row { display: flex; gap: 8px; flex-wrap: wrap; }
.input-row input { flex: 1 1 240px; }

input[type="text"], textarea, select {
  width: 100%;
  border: 1px solid var(--line);
  background: var(--surface-2);
  color: var(--text);
  border-radius: 11px;
  padding: 11px 13px;
  font-size: 15px;
  font-family: inherit;
  min-height: 44px;
}
input[type="text"]:focus, textarea:focus, select:focus {
  outline: 2px solid color-mix(in srgb, var(--primary) 50%, transparent);
  outline-offset: 0; border-color: var(--primary);
}
#answer-input { font-size: 17px; letter-spacing: .2px; }
textarea { resize: vertical; line-height: 1.6; }

.feedback {
  margin-top: 16px; padding: 13px 15px; border-radius: 12px; font-size: 14px;
}
.feedback.correct { background: var(--ok-bg); color: var(--ok); }
.feedback.wrong { background: var(--bad-bg); color: var(--bad); }
.feedback.skipped { background: var(--skip-bg); color: var(--skip); }
.feedback .answer-line {
  margin-top: 6px; font-size: 15px; font-weight: 700;
  color: var(--text); word-break: break-word;
}
.feedback .answer-line code {
  background: color-mix(in srgb, var(--text) 8%, transparent);
  padding: 2px 7px; border-radius: 6px; font-size: 14.5px;
}

.hint-box { margin-top: 14px; padding: 14px; border-radius: 12px; background: var(--surface-2); }
.hint-box .sentence { margin: 4px 0 0; font-size: 16px; line-height: 1.6; }

/* ---------- 底部固定栏 ---------- */
.bottom-bar {
  position: fixed;
  left: 0; right: 0; bottom: 0;
  z-index: 40;
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  backdrop-filter: blur(12px);
  border-top: 1px solid var(--line);
  padding: 12px 16px calc(12px + env(safe-area-inset-bottom));
}
.bottom-inner { display: flex; gap: 10px; max-width: 980px; margin: 0 auto; }

/* ---------- 结算 ---------- */
.result h3 { margin: 0 0 16px; font-size: 19px; }
.result-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); gap: 10px; }
.result-cell { background: var(--surface-2); border-radius: 12px; padding: 14px; text-align: center; }
.result-cell .num { font-size: 26px; font-weight: 800; line-height: 1.1; }
.result-cell .cap { font-size: 12.5px; color: var(--muted); margin-top: 4px; }
.result-wrong { margin-top: 16px; }
.result-wrong h4 { margin: 0 0 8px; font-size: 13.5px; color: var(--muted); font-weight: 600; }
.wrong-item {
  display: flex; justify-content: space-between; gap: 12px;
  padding: 9px 12px; border: 1px solid var(--line); border-radius: 10px;
  font-size: 13.5px; margin-bottom: 6px; flex-wrap: wrap;
}
.wrong-item b { color: var(--bad); }

/* ---------- 对话框 ---------- */
dialog {
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  color: var(--text);
  padding: 0;
  width: min(520px, calc(100vw - 32px));
  box-shadow: 0 24px 60px rgba(10, 12, 30, .35);
}
dialog::backdrop { background: rgba(12, 14, 28, .45); backdrop-filter: blur(2px); }
.dialog-form { padding: 20px; display: grid; gap: 12px; }
.dialog-form.wide { width: min(640px, calc(100vw - 48px)); }
.dialog-form h3 { margin: 0 0 2px; font-size: 17px; }
.dialog-form label { display: grid; gap: 6px; font-size: 13px; color: var(--muted); }
.dialog-form label input, .dialog-form label textarea, .dialog-form label select { color: var(--text); }
.dialog-form menu { display: flex; justify-content: flex-end; gap: 8px; margin: 6px 0 0; padding: 0; }
.dialog-form code {
  background: var(--surface-2); padding: 1px 5px; border-radius: 5px; font-size: 12px;
}
.file-row input[type="file"] { padding: 9px; background: var(--surface-2); border-radius: 10px; }
.import-report {
  font-size: 12.5px; padding: 10px 12px; border-radius: 10px;
  background: var(--ok-bg); color: var(--ok); max-height: 140px; overflow: auto;
}
.import-report.has-error { background: var(--bad-bg); color: var(--bad); }

/* ---------- Toast ---------- */
.toast {
  position: fixed; left: 50%; transform: translateX(-50%);
  bottom: calc(var(--bar-h) + 18px + env(safe-area-inset-bottom));
  background: #1b1d29; color: #fff; padding: 10px 16px; border-radius: 11px;
  font-size: 13.5px; z-index: 90; box-shadow: 0 12px 30px rgba(0, 0, 0, .3);
  max-width: calc(100vw - 32px);
}
@media (prefers-color-scheme: dark) { .toast { background: #2c3040; } }

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .app { padding-top: 26px; }
  .prompt.zh { font-size: 32px; }
  .prompt.en { font-size: 34px; }
}
@media (max-width: 480px) {
  .prompt.zh, .prompt.en { font-size: 24px; }
  .card { padding: 17px; }
  .panel { padding: 14px; }
  .btn { padding: 8px 12px; }
}
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}