/* ============ MBA 管综学习平台 全局样式 ============ */
:root {
  --bg: #0e1420;
  --bg-2: #131c2e;
  --panel: rgba(255, 255, 255, 0.055);
  --panel-strong: rgba(255, 255, 255, 0.09);
  --line: rgba(255, 255, 255, 0.1);
  --text: #e8eef7;
  --text-dim: #9aa8bd;
  --text-mute: #6b7890;
  --blue: #4f7cff;
  --teal: #22b8a6;
  --orange: #f08c3c;
  --green: #34c98e;
  --red: #ef6363;
  --radius: 18px;
  --shadow: 0 18px 50px rgba(0, 0, 0, 0.35);
}

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

html, body { height: 100%; }

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", system-ui, sans-serif;
  background:
    radial-gradient(1200px 700px at 85% -10%, rgba(79, 124, 255, 0.16), transparent 60%),
    radial-gradient(1000px 600px at -10% 30%, rgba(34, 184, 166, 0.12), transparent 55%),
    radial-gradient(900px 600px at 50% 110%, rgba(240, 140, 60, 0.1), transparent 55%),
    var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.7;
}

a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; }

/* ---------- 顶部导航 ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; gap: 22px;
  padding: 14px 28px;
  background: rgba(14, 20, 32, 0.82);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}
.nav .logo { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 17px; }
.nav .logo .mark {
  width: 32px; height: 32px; border-radius: 10px;
  background: linear-gradient(135deg, var(--blue), var(--teal));
  display: grid; place-items: center; font-size: 16px;
}
.nav .links { display: flex; gap: 6px; margin-left: 12px; flex-wrap: wrap; }
.nav .links a {
  padding: 8px 14px; border-radius: 10px; color: var(--text-dim);
  font-size: 14.5px; transition: all .18s;
}
.nav .links a:hover { color: var(--text); background: var(--panel-strong); }
.nav .links a.active { color: #fff; background: var(--panel-strong); }
.nav .spacer { flex: 1; }
.nav .nav-badge { font-size: 13px; color: var(--text-dim); }

.wrap { max-width: 1180px; margin: 0 auto; padding: 28px 24px 80px; }

/* ---------- 通用卡片 ---------- */
.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  backdrop-filter: blur(8px);
}
.card.hoverable { transition: transform .18s, border-color .18s, background .18s; }
.card.hoverable:hover { transform: translateY(-4px); border-color: rgba(255,255,255,.2); background: var(--panel-strong); }

.btn {
  border: 1px solid var(--line);
  background: var(--panel-strong);
  color: var(--text);
  padding: 9px 18px; border-radius: 12px; font-size: 14px;
  transition: all .16s;
}
.btn:hover { background: rgba(255,255,255,.14); }
.btn.primary { background: linear-gradient(135deg, var(--blue), #6a93ff); border: none; color: #fff; }
.btn.primary:hover { filter: brightness(1.08); }
.btn.teal { background: linear-gradient(135deg, var(--teal), #35d6c2); border: none; color: #06231f; font-weight: 600; }
.btn.ghost { background: transparent; }
.btn.small { padding: 6px 12px; font-size: 13px; border-radius: 10px; }
.btn.danger { color: var(--red); border-color: rgba(239,99,99,.35); }

.tag {
  display: inline-flex; align-items: center; gap: 5px;
  font-size: 12.5px; padding: 3px 10px; border-radius: 999px;
  background: var(--panel-strong); color: var(--text-dim);
}
.tag.blue { color: #9db9ff; background: rgba(79,124,255,.15); }
.tag.teal { color: #7fe3d4; background: rgba(34,184,166,.15); }
.tag.orange { color: #ffc08a; background: rgba(240,140,60,.15); }
.tag.red { color: #ff9b9b; background: rgba(239,99,99,.15); }
.tag.green { color: #8ce9bd; background: rgba(52,201,142,.15); }

/* 难度星 / 考频 */
.stars { color: #ffcf5c; letter-spacing: 1px; font-size: 13px; }
.muted { color: var(--text-mute); font-size: 13px; }

/* ---------- 网格 ---------- */
.grid { display: grid; gap: 18px; }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid.cols-4 { grid-template-columns: repeat(4, 1fr); }
@media (max-width: 960px) {
  .grid.cols-3, .grid.cols-4 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 640px) {
  .grid.cols-2, .grid.cols-3, .grid.cols-4 { grid-template-columns: 1fr; }
  .nav { padding: 12px 16px; gap: 12px; }
}

/* ---------- 页面标题 ---------- */
.page-head { margin: 8px 0 24px; }
.page-head h1 { font-size: 26px; letter-spacing: .5px; }
.page-head p { color: var(--text-dim); margin-top: 6px; }

/* ---------- 进度条 ---------- */
.progress { height: 8px; border-radius: 999px; background: rgba(255,255,255,.08); overflow: hidden; }
.progress > i { display: block; height: 100%; border-radius: 999px; background: linear-gradient(90deg, var(--blue), var(--teal)); }

/* ---------- 题目卡片 ---------- */
.q-meta { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 12px; }
.q-stem { font-size: 16px; margin-bottom: 18px; white-space: pre-line; }
.opt-list { display: flex; flex-direction: column; gap: 10px; }
.opt {
  display: flex; gap: 12px; align-items: flex-start;
  padding: 13px 16px; border: 1px solid var(--line); border-radius: 14px;
  background: rgba(255,255,255,.03); transition: all .15s; text-align: left; color: var(--text); width: 100%;
}
.opt:hover { background: var(--panel-strong); }
.opt .key {
  flex: none; width: 28px; height: 28px; border-radius: 9px;
  display: grid; place-items: center; font-weight: 700; font-size: 14px;
  background: var(--panel-strong); color: var(--text-dim);
}
.opt.selected { border-color: var(--blue); background: rgba(79,124,255,.12); }
.opt.selected .key { background: var(--blue); color: #fff; }
.opt.correct { border-color: var(--green); background: rgba(52,201,142,.12); }
.opt.correct .key { background: var(--green); color: #06231a; }
.opt.wrong { border-color: var(--red); background: rgba(239,99,99,.1); }
.opt.wrong .key { background: var(--red); color: #fff; }
.opt.disabled { cursor: default; }

.analysis-box {
  margin-top: 18px; padding: 18px; border-radius: 14px;
  background: rgba(34,184,166,.08); border: 1px solid rgba(34,184,166,.2);
}
.analysis-box h4 { color: var(--teal); margin-bottom: 8px; }
.analysis-box.wrong { background: rgba(239,99,99,.07); border-color: rgba(239,99,99,.2); }
.analysis-box.wrong h4 { color: var(--red); }

.result-line { font-weight: 700; margin-bottom: 8px; }
.result-line.ok { color: var(--green); }
.result-line.no { color: var(--red); }

/* ---------- 知识点状态 ---------- */
.status-pill { font-size: 12px; padding: 3px 10px; border-radius: 999px; }
.status-0 { background: rgba(255,255,255,.08); color: var(--text-mute); }
.status-1 { background: rgba(79,124,255,.15); color: #9db9ff; }
.status-2 { background: rgba(240,140,60,.15); color: #ffc08a; }
.status-3 { background: rgba(52,201,142,.15); color: #8ce9bd; }

/* ---------- 3D 容器 ---------- */
#home-canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }
.scene-box { position: relative; border-radius: var(--radius); overflow: hidden; border: 1px solid var(--line); background: linear-gradient(180deg, rgba(20,28,46,.6), rgba(12,17,28,.6)); }
.mini-canvas { width: 100%; height: 260px; display: block; }

/* ---------- 统计卡 ---------- */
.stat-num { font-size: 30px; font-weight: 800; letter-spacing: .5px; }
.stat-label { color: var(--text-dim); font-size: 13.5px; margin-top: 2px; }

/* ---------- 列表 ---------- */
.list-row { display: flex; align-items: center; gap: 14px; padding: 14px 4px; border-bottom: 1px solid var(--line); }
.list-row:last-child { border-bottom: none; }

.empty { text-align: center; color: var(--text-mute); padding: 50px 20px; }
.empty .big { font-size: 40px; margin-bottom: 10px; }

/* 章节折叠 */
.chapter-block { margin-bottom: 18px; }
.chapter-title { display: flex; align-items: center; gap: 10px; font-weight: 600; font-size: 16px; margin-bottom: 12px; }

.toast {
  position: fixed; left: 50%; bottom: 36px; transform: translateX(-50%);
  background: rgba(20,28,46,.95); border: 1px solid var(--line);
  padding: 12px 20px; border-radius: 12px; z-index: 200;
  opacity: 0; transition: opacity .2s; pointer-events: none;
}
.toast.show { opacity: 1; }

.row-between { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.mt { margin-top: 18px; }
.mt-sm { margin-top: 10px; }
.dim { color: var(--text-dim); }