:root {
  --bg: #0f172a;
  --bg-soft: #1e293b;
  --card: #1e293b;
  --card-hover: #263449;
  --text: #e2e8f0;
  --text-dim: #94a3b8;
  --accent: #38bdf8;
  --accent-2: #34d399;
  --warn: #fbbf24;
  --danger: #f87171;
  --border: #334155;
  --radius: 12px;
  --shadow: 0 4px 20px rgba(0,0,0,.35);
}

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

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased;
}

#app { max-width: 860px; margin: 0 auto; padding: 0 16px 80px; }

.hidden { display: none !important; }

/* 顶栏 */
.topbar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 0 12px;
  position: sticky; top: 0; background: var(--bg); z-index: 20;
}
.brand { display: flex; align-items: center; gap: 8px; font-weight: 700; font-size: 18px; }
.brand-icon { font-size: 22px; }
.top-actions { display: flex; gap: 8px; }

.icon-btn {
  background: var(--bg-soft); border: 1px solid var(--border); color: var(--text);
  border-radius: 10px; width: 40px; height: 40px; font-size: 16px; cursor: pointer;
  transition: background .15s;
}
.icon-btn:hover { background: var(--card-hover); }

.primary-btn {
  background: var(--accent); color: #0f172a; border: none; border-radius: 10px;
  padding: 10px 18px; font-weight: 700; cursor: pointer; font-size: 14px;
}
.primary-btn:hover { filter: brightness(1.1); }

/* 书架 */
.book-tabs { display: flex; gap: 8px; margin-bottom: 12px; }
.book-tab {
  flex: 1; padding: 12px; border-radius: var(--radius); border: 1px solid var(--border);
  background: var(--bg-soft); color: var(--text-dim); font-size: 15px; font-weight: 600; cursor: pointer;
}
.book-tab.active { background: var(--accent); color: #0f172a; border-color: var(--accent); }

.progress-bar-wrap { display: flex; align-items: center; gap: 12px; margin-bottom: 16px; }
.progress-bar { flex: 1; height: 8px; background: var(--bg-soft); border-radius: 4px; overflow: hidden; }
.progress-fill { height: 100%; width: 0; background: linear-gradient(90deg, var(--accent), var(--accent-2)); border-radius: 4px; transition: width .4s; }
.progress-text { color: var(--text-dim); font-size: 13px; white-space: nowrap; }

.lesson-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr)); gap: 10px; }
.lesson-card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 12px 14px; cursor: pointer; transition: transform .12s, background .15s, border-color .15s;
}
.lesson-card:hover { background: var(--card-hover); transform: translateY(-2px); border-color: var(--accent); }
.lesson-card .lc-no { font-size: 12px; color: var(--text-dim); font-weight: 600; }
.lesson-card .lc-title { font-size: 14px; font-weight: 600; margin-top: 3px; line-height: 1.4; }
.lesson-card .lc-status { display: inline-block; margin-top: 8px; font-size: 11px; padding: 2px 8px; border-radius: 20px; }
.lc-status.s0 { background: #33415555; color: var(--text-dim); }
.lc-status.s1 { background: #fbbf2433; color: var(--warn); }
.lc-status.s2 { background: #34d39933; color: var(--accent-2); }

/* 课文视图 */
.lesson-header { display: flex; align-items: center; gap: 12px; padding: 12px 0; }
.lesson-title-wrap { flex: 1; min-width: 0; }
.lesson-no { font-size: 12px; color: var(--accent); font-weight: 700; }
.lesson-title { font-size: 17px; font-weight: 700; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.lesson-toolbar { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 14px; }
.tool-btn {
  background: var(--bg-soft); border: 1px solid var(--border); color: var(--text);
  border-radius: 8px; padding: 8px 12px; font-size: 13px; cursor: pointer;
}
.tool-btn.active { border-color: var(--accent); color: var(--accent); }
.tool-btn:hover { background: var(--card-hover); }

.lesson-body { display: flex; flex-direction: column; gap: 6px; }
.sentence {
  padding: 10px 12px; border-radius: 10px; cursor: pointer; border: 1px solid transparent;
  transition: background .15s;
}
.sentence:hover { background: var(--bg-soft); }
.sentence .sen-en { font-size: 16px; line-height: 1.65; }
.sentence .sen-zh { font-size: 13.5px; color: var(--text-dim); margin-top: 4px; line-height: 1.6; }
.sentence.playing { background: var(--bg-soft); border-color: var(--accent); }
.sentence .sen-en.dim { color: var(--text-dim); }

/* 背诵视图 */
.recite-header { display: flex; align-items: center; gap: 12px; padding: 12px 0; }
.recite-progress { color: var(--text-dim); font-size: 13px; font-weight: 600; white-space: nowrap; }
.recite-mode-tabs { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 14px; }
.recite-tab {
  background: var(--bg-soft); border: 1px solid var(--border); color: var(--text-dim);
  border-radius: 8px; padding: 8px 14px; font-size: 13px; cursor: pointer;
}
.recite-tab.active { border-color: var(--accent); color: var(--accent); background: #38bdf81a; }

.recite-stage {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  min-height: 240px; padding: 24px; margin-bottom: 16px;
  display: flex; flex-direction: column; justify-content: center;
}
.recite-stage .q-zh { font-size: 17px; line-height: 1.7; color: var(--text); }
.recite-stage .q-en { font-size: 16px; line-height: 1.7; margin-top: 14px; color: var(--accent-2); }
.recite-stage .q-en.hidden-text { color: transparent; user-select: none; text-shadow: 0 0 10px rgba(148,163,184,.5); }
.recite-stage .q-en.blank-word { color: var(--warn); font-weight: 700; }
.recite-stage .q-hint { font-size: 15px; line-height: 1.7; margin-top: 14px; color: var(--text-dim); letter-spacing: .04em; }
.recite-stage .q-done { color: var(--accent-2); font-size: 15px; margin-top: 14px; font-weight: 600; }

.recite-controls { display: flex; gap: 10px; flex-wrap: wrap; justify-content: center; }
.ctrl-btn {
  border: none; border-radius: 12px; padding: 14px 0; font-size: 15px; font-weight: 700; cursor: pointer;
  flex: 1; min-width: 90px; max-width: 160px; transition: filter .15s, transform .1s;
}
.ctrl-btn:active { transform: scale(.97); }
.ctrl-btn.good { background: #34d39933; color: var(--accent-2); border: 1px solid #34d39966; }
.ctrl-btn.mid { background: #fbbf2433; color: var(--warn); border: 1px solid #fbbf2466; }
.ctrl-btn.bad { background: #f8717133; color: var(--danger); border: 1px solid #f8717166; }
.ctrl-btn.reveal { background: var(--accent); color: #0f172a; }
.ctrl-btn.ghost { background: var(--bg-soft); color: var(--text-dim); border: 1px solid var(--border); }

/* 弹窗 */
.modal {
  position: fixed; inset: 0; background: rgba(2,6,23,.75); backdrop-filter: blur(4px);
  display: flex; align-items: center; justify-content: center; z-index: 100; padding: 20px;
}
.modal-card {
  background: var(--card); border: 1px solid var(--border); border-radius: 16px;
  padding: 24px; width: 100%; max-width: 460px; max-height: 80vh; overflow-y: auto;
}
.modal-card h3 { margin-bottom: 14px; }
.modal-close {
  width: 100%; margin-top: 14px; padding: 12px; border: 1px solid var(--border);
  background: var(--bg-soft); color: var(--text); border-radius: 10px; cursor: pointer;
}
#search-input {
  width: 100%; padding: 12px; border-radius: 10px; border: 1px solid var(--border);
  background: var(--bg); color: var(--text); font-size: 15px; margin-bottom: 12px;
}
.search-results { display: flex; flex-direction: column; gap: 8px; }
.search-item {
  padding: 10px 12px; border: 1px solid var(--border); border-radius: 10px; cursor: pointer;
  background: var(--bg-soft);
}
.search-item:hover { border-color: var(--accent); }
.search-item .si-title { font-weight: 600; font-size: 14px; }
.search-item .si-snippet { color: var(--text-dim); font-size: 12.5px; margin-top: 3px; line-height: 1.5; }
.stats-row { display: flex; justify-content: space-between; padding: 8px 0; border-bottom: 1px dashed var(--border); font-size: 14px; }
.stats-row span:last-child { font-weight: 700; }

@media (max-width: 520px) {
  .lesson-grid { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); }
  .sentence .sen-en { font-size: 15px; }
  .recite-stage { padding: 18px; }
}