/* ============ 设计令牌与基础 ============ */
:root {
  --ink: #16213a;
  --ink-2: #33415e;
  --muted: #66779a;
  --paper: #f4f6fb;
  --card: #ffffff;
  --border: #e3e9f4;
  --primary: #1d4fd7;
  --primary-deep: #173faa;
  --primary-soft: #e9effc;
  --amber: #d97a16;
  --amber-soft: #fdf1e2;
  --green: #0d9668;
  --green-soft: #e3f6ee;
  --violet: #7c4dff;
  --violet-soft: #f0eaff;
  --red: #d64545;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(22, 33, 58, .05), 0 8px 24px -12px rgba(22, 33, 58, .12);
  --shadow-lg: 0 2px 4px rgba(22, 33, 58, .04), 0 12px 28px -10px rgba(23, 63, 170, .18), 0 32px 64px -32px rgba(23, 63, 170, .22);
  --glass: rgba(255, 255, 255, .78);
  --glass-border: rgba(255, 255, 255, .65);
  --band-a: var(--primary);
  --band-b: #5585f2;
  --font-body: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", sans-serif;
  --font-display: Georgia, "Times New Roman", "Songti SC", serif;
}

/* 年龄段主题（T010）：L0-L4 卡通 / L5-L8 中小学 / L9-LU 高中成人 */
body.band-kid { --band-a: #7ec3ff; --band-b: #ff9ec6; --radius: 20px; }
body.band-junior { --band-a: #3b56c4; --band-b: #8b5cf6; --radius: 14px; }
body.band-senior { --band-a: #2f6d8f; --band-b: #c9a45c; --radius: 10px; }

* { margin: 0; padding: 0; box-sizing: border-box; }
html { font-size: 16px; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-body);
  background:
    radial-gradient(1100px 520px at 88% -8%, rgba(124, 77, 255, .09), transparent 60%),
    radial-gradient(900px 480px at -12% 2%, rgba(29, 79, 215, .09), transparent 55%),
    radial-gradient(760px 520px at 50% 112%, rgba(13, 150, 104, .07), transparent 60%),
    var(--paper);
  background-attachment: fixed;
  color: var(--ink);
  line-height: 1.6;
  min-height: 100vh;
}
body.has-tab { padding-bottom: 66px; }
@media (min-width: 768px) { body.has-tab { padding-bottom: 0; } }

h1, h2, h3 { line-height: 1.3; color: var(--ink); }
a { color: var(--primary); text-decoration: none; }
button { font-family: inherit; cursor: pointer; }
input, select, textarea { font-family: inherit; font-size: 1rem; }
.hidden { display: none !important; }

.app-boot {
  min-height: 46vh; display: grid; place-items: center; padding: 48px 20px;
  color: var(--muted); font-size: 15px; letter-spacing: .06em;
}
.app-boot::before {
  content: ""; width: 20px; height: 20px; margin-right: 10px; display: inline-block;
  border: 2px solid rgba(29,79,215,.18); border-top-color: var(--primary);
  border-radius: 50%; vertical-align: -5px; animation: appBootSpin .75s linear infinite;
}
@keyframes appBootSpin { to { transform: rotate(360deg); } }

.noscript-warning {
  margin: 40px auto; max-width: 480px; padding: 20px;
  background: #fff; border: 1px solid var(--border); border-radius: var(--radius);
  text-align: center; color: var(--ink-2);
}

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 18px; }

/* 蓝斯值等数字用学术衬线体 */
.lx, .serif { font-family: var(--font-display); letter-spacing: .01em; }

/* ============ 按钮 ============ */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 44px; padding: 10px 22px;
  border: 1px solid transparent; border-radius: 12px;
  background: linear-gradient(180deg, #3a6df0 0%, var(--primary) 100%); color: #fff;
  font-size: .98rem; font-weight: 600;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .22), 0 10px 20px -10px rgba(29, 79, 215, .5);
  transition: background .18s, transform .12s, box-shadow .18s;
}
.btn:hover { background: linear-gradient(180deg, #2f5cdf 0%, var(--primary-deep) 100%); transform: translateY(-1px); box-shadow: inset 0 1px 0 rgba(255,255,255,.22), 0 14px 26px -10px rgba(29, 79, 215, .55); }
.btn:active { transform: scale(.97); }
.btn:focus-visible { outline: 3px solid rgba(29, 79, 215, .35); outline-offset: 2px; }
.btn.block { width: 100%; }
.btn.lg { min-height: 50px; font-size: 1.05rem; padding: 12px 28px; }
.btn.sm { min-height: 36px; padding: 6px 14px; font-size: .88rem; border-radius: 9px; }
.btn.ghost { background: rgba(255, 255, 255, .85); color: var(--ink-2); border-color: var(--border); box-shadow: 0 2px 8px -4px rgba(22, 33, 58, .12); }
.btn.ghost:hover { background: #fff; border-color: #cbd5e8; transform: translateY(-1px); }
.btn.soft { background: var(--primary-soft); color: var(--primary); box-shadow: none; }
.btn.soft:hover { background: #dbe6fb; }
.btn:disabled, .btn.disabled { background: #c9d3e6; color: #fff; cursor: not-allowed; pointer-events: none; box-shadow: none; }
.btn.done { background: var(--green-soft); color: var(--green); box-shadow: none; }

/* ============ 表单 ============ */
.field { margin-bottom: 16px; }
.field label { display: block; font-size: .9rem; font-weight: 600; color: var(--ink-2); margin-bottom: 6px; }
.field .hint { font-size: .82rem; color: var(--muted); margin-top: 5px; }
.input, .select {
  width: 100%; min-height: 46px; padding: 10px 14px;
  border: 1.5px solid var(--border); border-radius: 10px;
  background: #fff; color: var(--ink);
  transition: border-color .15s, box-shadow .15s;
}
.input:focus, .select:focus {
  outline: none; border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(29, 79, 215, .14);
}
.input::placeholder { color: #a3aec6; }
.form-error {
  display: none; margin: 10px 0 0; padding: 9px 13px;
  background: #fdecec; color: var(--red); border-radius: 9px; font-size: .9rem;
}
.form-error.show { display: block; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}