:root {
  --bg: #f4f1ea;
  --paper: #fffdf8;
  --ink: #1f2430;
  --ink2: #5b6472;
  --line: #e2dcd0;
  --brand: #1f4e79;
  --brand2: #2f7bbf;
  --ok: #2e8b57;
  --bad: #c0392b;
  --warn: #b8860b;
  --shadow: 0 1px 2px rgba(31, 36, 48, .06), 0 8px 24px rgba(31, 36, 48, .06);
}
* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "PingFang SC", "Noto Sans SC", "Helvetica Neue", Arial, sans-serif;
  padding-bottom: env(safe-area-inset-bottom);
  overscroll-behavior-y: contain;
}
a { color: var(--brand2); }
.wrap { max-width: 720px; margin: 0 auto; padding: 14px 14px 40px; }

/* 顶栏 */
.top {
  position: sticky; top: 0; z-index: 20;
  background: rgba(244, 241, 234, .92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.top-in { max-width: 720px; margin: 0 auto; padding: 10px 14px; display: flex; align-items: center; gap: 10px; }
.top h1 { font-size: 16px; margin: 0; font-weight: 650; letter-spacing: .3px; flex: 1; }
.top h1 small { display: block; font-size: 11px; font-weight: 400; color: var(--ink2); letter-spacing: 0; }
.icon-btn {
  border: 1px solid var(--line); background: var(--paper); color: var(--ink2);
  border-radius: 10px; padding: 6px 10px; font-size: 13px; cursor: pointer;
}
.icon-btn:active { transform: scale(.97); }

/* 卡片 */
.card {
  background: var(--paper); border: 1px solid var(--line); border-radius: 16px;
  padding: 16px; box-shadow: var(--shadow); margin-bottom: 14px;
}
.card h2 { margin: 0 0 10px; font-size: 15px; font-weight: 650; }
.muted { color: var(--ink2); font-size: 13px; }
.row { display: flex; gap: 10px; }
.row > * { flex: 1; }

/* 进度 */
.hero { text-align: center; padding: 22px 16px 18px; }
.hero .big { font-size: 40px; font-weight: 700; color: var(--brand); line-height: 1.1; }
.hero .big span { font-size: 17px; color: var(--ink2); font-weight: 500; }
.bar { height: 10px; border-radius: 99px; background: #e9e3d6; overflow: hidden; margin: 12px 0 6px; }
.bar > i { display: block; height: 100%; width: 0; border-radius: 99px; background: linear-gradient(90deg, var(--brand2), var(--brand)); transition: width .5s ease; }
.stats3 { display: flex; text-align: center; margin-top: 14px; }
.stats3 div { flex: 1; }
.stats3 b { display: block; font-size: 20px; font-weight: 700; }
.stats3 em { font-style: normal; font-size: 11px; color: var(--ink2); }

/* 按钮 */
.btn {
  display: block; width: 100%; border: 0; border-radius: 14px;
  padding: 15px; font-size: 16px; font-weight: 650; cursor: pointer;
  background: var(--brand); color: #fff; letter-spacing: 1px;
  box-shadow: 0 6px 18px rgba(31, 78, 121, .22);
}
.btn:active { transform: translateY(1px); }
.btn.ghost { background: transparent; color: var(--brand); border: 1px solid #c9d6e3; box-shadow: none; font-weight: 600; }
.btn.sm { padding: 10px; font-size: 14px; border-radius: 11px; }
.btn[disabled] { opacity: .5; pointer-events: none; }

/* 知识点列表 */
.kp-group { margin-bottom: 6px; }
.kp-group > h3 {
  font-size: 12px; color: var(--ink2); font-weight: 600; margin: 16px 2px 8px;
  letter-spacing: .5px;
}
.kp {
  display: flex; align-items: center; gap: 10px; padding: 11px 12px;
  background: var(--paper); border: 1px solid var(--line); border-radius: 12px; margin-bottom: 8px;
  font-size: 14px;
}
.kp .dot { width: 9px; height: 9px; border-radius: 50%; background: #cfd6df; flex: none; }
.kp .dot.m { background: var(--ok); }
.kp .dot.w { background: var(--bad); }
.kp .nm { flex: 1; }
.kp .meta { font-size: 11px; color: var(--ink2); white-space: nowrap; }
.pips { display: flex; gap: 3px; }
.pips i { width: 7px; height: 7px; border-radius: 50%; background: #dfe4ea; display: block; }
.pips i.on { background: var(--ok); }

/* 练习 */
.qhead { display: flex; align-items: center; gap: 8px; margin-bottom: 12px; flex-wrap: wrap; }
.tag {
  font-size: 11px; padding: 3px 8px; border-radius: 99px;
  background: #eaf1f8; color: var(--brand); border: 1px solid #d5e3f0;
}
.tag.t { background: #fbf3e0; color: var(--warn); border-color: #f0e2bf; }
.qtext { font-size: 17px; line-height: 1.7; font-weight: 550; margin: 4px 0 16px; }
.opt {
  display: flex; gap: 11px; align-items: flex-start;
  border: 1px solid var(--line); background: #fff; border-radius: 12px;
  padding: 13px 14px; margin-bottom: 10px; cursor: pointer; font-size: 15px; line-height: 1.55;
  transition: background .15s, border-color .15s;
}
.opt .k {
  width: 22px; height: 22px; border-radius: 50%; border: 1px solid #c8d0d9; flex: none;
  display: grid; place-items: center; font-size: 12px; color: var(--ink2); margin-top: 1px;
}
.opt.sel { border-color: var(--brand2); background: #f2f8fd; }
.opt.sel .k { background: var(--brand2); color: #fff; border-color: var(--brand2); }
.opt.right { border-color: var(--ok); background: #eef8f1; }
.opt.right .k { background: var(--ok); color: #fff; border-color: var(--ok); }
.opt.wrong { border-color: var(--bad); background: #fdf1f0; }
.opt.wrong .k { background: var(--bad); color: #fff; border-color: var(--bad); }
.opt.lock { pointer-events: none; }

.fb { border-radius: 12px; padding: 13px 14px; margin-top: 6px; font-size: 14px; line-height: 1.7; }
.fb.ok { background: #eef8f1; border: 1px solid #cfe9d9; }
.fb.no { background: #fdf1f0; border: 1px solid #f3d3cf; }
.fb b { font-weight: 700; }
.fb .exp { color: var(--ink2); margin-top: 6px; font-size: 13.5px; }
.fb .streak { margin-top: 8px; font-size: 13px; font-weight: 600; }
.mini { font-size: 11.5px; color: var(--ink2); text-align: center; margin-top: 14px; }

/* 弹层 */
.mask {
  position: fixed; inset: 0; background: rgba(20, 24, 32, .45); z-index: 50;
  display: none; align-items: center; justify-content: center; padding: 22px;
}
.mask.on { display: flex; }
.sheet {
  background: var(--paper); border-radius: 18px; padding: 22px; max-width: 380px; width: 100%;
  text-align: center; box-shadow: 0 20px 50px rgba(0, 0, 0, .25);
}
.sheet h3 { margin: 4px 0 8px; font-size: 18px; }
.sheet p { color: var(--ink2); font-size: 14px; margin: 0 0 16px; }
.emoji { font-size: 40px; line-height: 1; }

/* 统计表 */
.tbl { width: 100%; border-collapse: collapse; font-size: 13px; }
.tbl th, .tbl td { padding: 8px 6px; border-bottom: 1px solid #eee8dc; text-align: left; }
.tbl th { color: var(--ink2); font-weight: 600; font-size: 11.5px; }
.tbl td.num { text-align: right; font-variant-numeric: tabular-nums; }
.minibar { height: 5px; border-radius: 99px; background: #eee8dc; overflow: hidden; min-width: 46px; }
.minibar > i { display: block; height: 100%; background: var(--brand2); }
.rec { font-size: 12.5px; padding: 7px 0; border-bottom: 1px dashed #eee8dc; display: flex; gap: 8px; }
.rec .ok { color: var(--ok); }
.rec .no { color: var(--bad); }
.toast {
  position: fixed; left: 50%; bottom: 26px; transform: translate(-50%, 20px);
  background: #1f2430; color: #fff; font-size: 13.5px; padding: 10px 18px; border-radius: 99px;
  opacity: 0; transition: all .25s; z-index: 99; pointer-events: none; max-width: 86vw; text-align: center;
}
.toast.on { opacity: .95; transform: translate(-50%, 0); }
.hide { display: none !important; }

/* 学习模式 */
.sel {
  flex: 1; min-width: 0; max-width: 260px;
  border: 1px solid var(--line); background: var(--paper); color: var(--ink);
  border-radius: 10px; padding: 8px 10px; font-size: 13px; font-family: inherit;
  appearance: none; -webkit-appearance: none;
  background-image: linear-gradient(45deg, transparent 50%, #8b93a1 50%), linear-gradient(135deg, #8b93a1 50%, transparent 50%);
  background-position: calc(100% - 16px) 50%, calc(100% - 11px) 50%;
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
}
.study-opt { background: #fbfbf9; }
.study-opt.ans { border-color: var(--ok); background: #eef8f1; }
.study-opt.ans .k { background: var(--ok); color: #fff; border-color: var(--ok); }
.study-opt .k { color: #9aa3ae; }
.study-opt.ans .k { color: #fff; }
.ansline { font-size: 13.5px; font-weight: 650; color: var(--ok); margin-top: 8px; }