/* ============================================
   小学做题工作台 · 设计系统
   基调：米白底 / Action Blue / 圆角 14-18px
   ============================================ */
:root {
  --bg: #f5f5f7;
  --card: #ffffff;
  --text: #1d1d1f;
  --text2: #6e6e73;
  --text3: #a1a1a6;
  --line: #e5e5ea;
  --blue: #0066cc;
  --blue-soft: #e8f2fd;
  --green: #34a853;
  --green-soft: #e6f4ea;
  --red: #e5484d;
  --red-soft: #fdebec;
  --orange: #d9741e;
  --orange-soft: #fdf0e6;
  --purple: #7c5ce0;
  --purple-soft: #f1edfb;
  --radius: 16px;
  --radius-sm: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,.06), 0 4px 16px rgba(0,0,0,.04);
  --shadow-lg: 0 4px 12px rgba(0,0,0,.08), 0 12px 32px rgba(0,0,0,.06);
  --safe-b: env(safe-area-inset-bottom, 0px);
  --safe-t: env(safe-area-inset-top, 0px);
}
* { margin:0; padding:0; box-sizing:border-box; -webkit-tap-highlight-color:transparent; }
html { -webkit-text-size-adjust:100%; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", "Microsoft YaHei", sans-serif;
  background: var(--bg); color: var(--text); font-size: 15px; line-height: 1.55;
  min-height: 100vh; -webkit-font-smoothing: antialiased;
}
button { font-family: inherit; border: none; background: none; cursor: pointer; color: inherit; }
input, textarea, select { font-family: inherit; font-size: 15px; color: var(--text); }
img { display: block; max-width: 100%; }

/* ---------- 落地页 ---------- */
.landing-body { display:flex; align-items:center; justify-content:center; min-height:100vh; padding:24px; }
.landing-wrap { width:100%; max-width:420px; text-align:center; }
.landing-brand { margin-bottom:36px; }
.landing-logo { font-size:56px; margin-bottom:12px; }
.landing-brand h1 { font-size:26px; font-weight:700; letter-spacing:.5px; }
.landing-sub { color:var(--text2); font-size:14px; margin-top:8px; }
.landing-cards { display:flex; flex-direction:column; gap:16px; }
.landing-card {
  display:block; background:var(--card); border-radius:var(--radius); padding:24px;
  text-decoration:none; box-shadow:var(--shadow); text-align:left; transition:transform .15s;
}
.landing-card:active { transform:scale(.98); }
.card-icon {
  width:52px; height:52px; border-radius:14px; display:flex; align-items:center;
  justify-content:center; font-size:28px; margin-bottom:14px;
}
.card-title { font-size:19px; font-weight:700; color:var(--text); }
.card-desc { font-size:13px; color:var(--text2); margin-top:4px; }
.card-btn { display:inline-block; margin-top:14px; font-size:14px; font-weight:600; color:var(--blue); }
.landing-foot { color:var(--text3); font-size:12px; margin-top:28px; }

/* ---------- App 外壳 ---------- */
.app { max-width:560px; margin:0 auto; min-height:100vh; position:relative; padding-bottom:calc(76px + var(--safe-b)); }
.app-header {
  position:sticky; top:0; z-index:50; background:rgba(245,245,247,.92); backdrop-filter:blur(14px);
  -webkit-backdrop-filter:blur(14px); padding:calc(12px + var(--safe-t)) 16px 12px; border-bottom:1px solid var(--line);
  display:flex; align-items:center; gap:12px;
}
.app-header h2 { font-size:18px; font-weight:700; flex:1; overflow:hidden; text-overflow:ellipsis; white-space:nowrap; }
.app-header .back { font-size:22px; width:32px; height:32px; display:flex; align-items:center; justify-content:center; border-radius:10px; color:var(--blue); }
.app-header .head-role {
  font-size:11px; font-weight:600; color:var(--blue); background:var(--blue-soft);
  padding:3px 10px; border-radius:20px;
}
.page { padding:16px; }
.page.hidden { display:none; }

/* ---------- 底部导航 ---------- */
.tabbar {
  position:fixed; bottom:0; left:50%; transform:translateX(-50%); width:100%; max-width:560px;
  background:rgba(255,255,255,.94); backdrop-filter:blur(14px); -webkit-backdrop-filter:blur(14px);
  border-top:1px solid var(--line); display:flex; padding:6px 8px calc(6px + var(--safe-b));
  z-index:60;
}
.tabbar a {
  flex:1; display:flex; flex-direction:column; align-items:center; gap:2px; padding:6px 0;
  text-decoration:none; color:var(--text3); font-size:10px; font-weight:600; border-radius:12px; transition:color .15s;
}
.tabbar a .tab-ico { font-size:22px; line-height:1; }
.tabbar a.active { color:var(--blue); }

/* ---------- 通用组件 ---------- */
.card { background:var(--card); border-radius:var(--radius); box-shadow:var(--shadow); padding:16px; margin-bottom:14px; }
.card-title { font-size:16px; font-weight:700; margin-bottom:10px; display:flex; align-items:center; justify-content:space-between; }
.section-label { font-size:12px; font-weight:700; color:var(--text3); letter-spacing:1px; margin:18px 4px 10px; }
.btn {
  display:inline-flex; align-items:center; justify-content:center; gap:6px;
  background:var(--blue); color:#fff; font-size:15px; font-weight:600;
  padding:12px 20px; border-radius:14px; transition:opacity .15s, transform .1s; width:100%;
}
.btn:active { opacity:.85; transform:scale(.985); }
.btn:disabled { opacity:.45; }
.btn.secondary { background:var(--blue-soft); color:var(--blue); }
.btn.ghost { background:transparent; color:var(--blue); }
.btn.gray { background:#f0f0f2; color:var(--text2); }
.btn.danger { background:var(--red-soft); color:var(--red); }
.btn.sm { padding:8px 14px; font-size:13px; border-radius:10px; width:auto; }
.chip {
  display:inline-flex; align-items:center; padding:5px 12px; border-radius:20px;
  background:#f2f2f4; color:var(--text2); font-size:12px; font-weight:600; cursor:pointer;
}
.chip.active { background:var(--blue); color:#fff; }
.chip-row { display:flex; flex-wrap:wrap; gap:8px; }
.empty {
  text-align:center; color:var(--text3); padding:48px 20px; font-size:14px;
}
.empty .e-ico { font-size:44px; margin-bottom:10px; }
.pill { display:inline-flex; align-items:center; gap:4px; font-size:11px; font-weight:600; padding:2px 9px; border-radius:20px; }
.pill.ok { background:var(--green-soft); color:var(--green); }
.pill.no { background:var(--red-soft); color:var(--red); }
.pill.warn { background:var(--orange-soft); color:var(--orange); }
.pill.info { background:var(--blue-soft); color:var(--blue); }
.badge { font-size:11px; font-weight:700; padding:2px 8px; border-radius:8px; }

/* ---------- 年级/科目选择 ---------- */
.grid-cols-3 { display:grid; grid-template-columns:repeat(3,1fr); gap:10px; }
.grid-cols-2 { display:grid; grid-template-columns:repeat(2,1fr); gap:10px; }
.sel-item {
  background:var(--card); border-radius:14px; padding:14px 8px; text-align:center;
  box-shadow:var(--shadow); cursor:pointer; transition:transform .1s;
}
.sel-item:active { transform:scale(.96); }
.sel-item .si-ico { font-size:26px; margin-bottom:6px; }
.sel-item .si-name { font-size:14px; font-weight:600; }
.sel-item .si-sub { font-size:11px; color:var(--text3); margin-top:2px; }
.sel-item.active { outline:2px solid var(--blue); background:var(--blue-soft); }

/* ---------- 题目卡片 ---------- */
.q-card { background:var(--card); border-radius:var(--radius); box-shadow:var(--shadow); padding:16px; margin-bottom:12px; }
.q-head { display:flex; justify-content:space-between; align-items:center; margin-bottom:8px; }
.q-no { font-weight:700; font-size:13px; color:var(--blue); }
.q-type { font-size:11px; color:var(--text3); }
.q-text { font-size:16px; line-height:1.7; margin-bottom:12px; white-space:pre-wrap; word-break:break-word; }
.q-sub { font-size:13px; color:var(--text2); }
.q-input {
  width:100%; min-height:44px; border:1.5px solid var(--line); border-radius:12px;
  padding:10px 12px; font-size:15px; resize:vertical; outline:none; transition:border .15s;
}
.q-input:focus { border-color:var(--blue); }
.q-options { display:flex; flex-direction:column; gap:8px; }
.q-opt {
  display:flex; align-items:center; gap:10px; border:1.5px solid var(--line); border-radius:12px;
  padding:11px 14px; cursor:pointer; transition:border .15s, background .15s;
}
.q-opt.selected { border-color:var(--blue); background:var(--blue-soft); }
.q-opt .opt-letter { font-weight:700; color:var(--text2); min-width:20px; }
.q-opt.selected .opt-letter { color:var(--blue); }

/* 判卷结果 */
.result-mark { width:34px; height:34px; border-radius:50%; display:flex; align-items:center; justify-content:center; font-size:20px; font-weight:800; color:#fff; flex-shrink:0; }
.result-mark.right { background:var(--green); }
.result-mark.wrong { background:var(--red); }
.result-mark.doubt { background:var(--orange); }
.result-row { display:flex; gap:10px; align-items:flex-start; margin-bottom:12px; }
.judge-evidence { background:#f8f8fa; border-radius:12px; padding:10px 12px; font-size:12.5px; color:var(--text2); margin-top:8px; line-height:1.6; }
.judge-evidence .ev-title { font-weight:700; color:var(--text); margin-bottom:4px; }

/* ---------- 学情 ---------- */
.stat-grid { display:grid; grid-template-columns:repeat(3,1fr); gap:10px; margin-bottom:14px; }
.stat-card { background:var(--card); border-radius:14px; padding:14px 10px; text-align:center; box-shadow:var(--shadow); }
.stat-card .s-num { font-size:24px; font-weight:800; }
.stat-card .s-label { font-size:11px; color:var(--text3); margin-top:2px; }
.stat-card.blue .s-num { color:var(--blue); }
.stat-card.green .s-num { color:var(--green); }
.stat-card.orange .s-num { color:var(--orange); }
.stat-card.red .s-num { color:var(--red); }
.bar-track { height:6px; border-radius:4px; background:#f0f0f2; overflow:hidden; }
.bar-fill { height:100%; border-radius:4px; background:var(--blue); transition:width .4s; }

/* ---------- 弹层 ---------- */
.toast {
  position:fixed; top:calc(60px + var(--safe-t)); left:50%; transform:translateX(-50%) translateY(-8px);
  background:rgba(29,29,31,.92); color:#fff; font-size:13px; padding:10px 18px; border-radius:12px;
  opacity:0; transition:opacity .25s, transform .25s; z-index:100; pointer-events:none; max-width:82%; text-align:center;
}
.toast.show { opacity:1; transform:translateX(-50%) translateY(0); }
.modal-mask {
  position:fixed; inset:0; background:rgba(0,0,0,.45); z-index:80; display:flex; align-items:flex-end; justify-content:center;
  opacity:0; pointer-events:none; transition:opacity .2s;
}
.modal-mask.show { opacity:1; pointer-events:auto; }
.modal-sheet {
  background:var(--card); width:100%; max-width:560px; border-radius:20px 20px 0 0; padding:20px 18px calc(20px + var(--safe-b));
  transform:translateY(100%); transition:transform .25s; max-height:82vh; overflow-y:auto;
}
.modal-mask.show .modal-sheet { transform:translateY(0); }
.modal-title { font-size:17px; font-weight:700; margin-bottom:14px; text-align:center; }

/* ---------- 图片上传 ---------- */
.upload-zone {
  border:2px dashed var(--line); border-radius:var(--radius); padding:32px 16px; text-align:center;
  background:var(--card); cursor:pointer; transition:border .15s;
}
.upload-zone:active { border-color:var(--blue); }
.upload-zone .u-ico { font-size:40px; margin-bottom:8px; }
.upload-zone .u-txt { font-size:14px; color:var(--text2); }
.upload-zone .u-sub { font-size:12px; color:var(--text3); margin-top:4px; }
.photo-preview { border-radius:var(--radius); overflow:hidden; margin-bottom:12px; box-shadow:var(--shadow); }
.photo-preview img { width:100%; }
.progress-steps { display:flex; align-items:center; justify-content:center; gap:6px; margin:18px 0; }
.pstep { display:flex; flex-direction:column; align-items:center; gap:4px; }
.pstep .ps-ico { width:36px; height:36px; border-radius:50%; background:#f0f0f2; display:flex; align-items:center; justify-content:center; font-size:16px; }
.pstep.done .ps-ico { background:var(--green-soft); }
.pstep.active .ps-ico { background:var(--blue-soft); animation:pulse 1.2s infinite; }
.pstep .ps-label { font-size:10px; color:var(--text3); white-space:nowrap; }
.pstep.done .ps-label { color:var(--green); }
.pstep.active .ps-label { color:var(--blue); }
.pline { width:22px; height:2px; background:var(--line); margin-bottom:18px; }
.pline.done { background:var(--green); }
@keyframes pulse { 0%,100% { transform:scale(1); } 50% { transform:scale(1.1); } }

/* 判定依据抽屉 */
.evidence-box { background:#f8f8fa; border-radius:12px; padding:12px; margin-top:10px; font-size:13px; line-height:1.7; }
.evidence-box .eb-title { font-weight:700; margin-bottom:6px; display:flex; align-items:center; gap:6px; }

/* ---------- 工具类 ---------- */
.row { display:flex; align-items:center; gap:10px; }
.row-between { display:flex; align-items:center; justify-content:space-between; gap:10px; }
.flex-1 { flex:1; }
.mt-8 { margin-top:8px; } .mt-12 { margin-top:12px; } .mt-16 { margin-top:16px; } .mt-24 { margin-top:24px; }
.mb-8 { margin-bottom:8px; } .mb-12 { margin-bottom:12px; } .mb-16 { margin-bottom:16px; }
.text2 { color:var(--text2); } .text3 { color:var(--text3); }
.small { font-size:12px; } .tiny { font-size:11px; }
.bold { font-weight:700; }
.center { text-align:center; }
.hidden { display:none !important; }
.divider { height:1px; background:var(--line); margin:14px 0; }
.fade-in { animation:fadeIn .3s ease; }
@keyframes fadeIn { from { opacity:0; transform:translateY(6px); } to { opacity:1; transform:none; } }