/* ============================================================
   Py2 通关 · 样式表
   ============================================================ */
:root {
  --blue: #306998;
  --blue-dark: #1f4e79;
  --yellow: #ffd43b;
  --bg: #f5f7fa;
  --card: #ffffff;
  --ink: #1c2733;
  --muted: #66788a;
  --line: #e3e9f0;
  --green: #2e9e5b;
  --green-bg: #e8f7ee;
  --red: #d64541;
  --red-bg: #fdeaea;
  --amber: #b7791f;
  --amber-bg: #fff6e0;
  --radius: 12px;
  --mono: "SF Mono", "JetBrains Mono", Consolas, "Courier New", monospace;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font-family: var(--sans); font-size: 15.5px; line-height: 1.65;
}

/* ---------- 顶栏 ---------- */
.topbar {
  display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 6px;
  padding: 10px 22px; background: linear-gradient(90deg, var(--blue-dark), var(--blue));
  color: #fff; position: sticky; top: 0; z-index: 50;
  box-shadow: 0 2px 8px rgba(20,40,70,.18);
}
.brand { color: #fff; text-decoration: none; font-size: 18px; display: flex; align-items: baseline; gap: 8px; white-space: nowrap; flex-shrink: 0; }
.brand b { font-size: 19px; }
.brand-sub { font-size: 12.5px; opacity: .85; }
.topbar-right { display: flex; gap: 10px; align-items: center; }
.chip {
  font-size: 12.5px; padding: 3px 10px; border-radius: 999px;
  background: rgba(255,255,255,.16); color: #fff; white-space: nowrap;
}
.chip-warn { background: var(--yellow); color: #5a4500; font-weight: 600; }
.chip-ok { background: #bde6c8; color: #0d5c2c; font-weight: 600; }
.chip-err { background: #f3b6b3; color: #7a1f1a; font-weight: 600; }

/* ---------- 导航 ---------- */
.mainnav {
  display: flex; gap: 4px; padding: 8px 18px; background: var(--card);
  border-bottom: 1px solid var(--line); position: sticky; top: 47px; z-index: 40;
  overflow-x: auto;
}
.mainnav a {
  color: var(--muted); text-decoration: none; padding: 6px 14px; border-radius: 8px;
  font-size: 14.5px; white-space: nowrap; font-weight: 500;
}
.mainnav a:hover { background: #eef3f8; color: var(--blue-dark); }
.mainnav a.active { background: var(--blue); color: #fff; }

/* ---------- 布局 ---------- */
#app { max-width: 1060px; margin: 0 auto; padding: 22px 18px 60px; }
.loading-page { text-align: center; color: var(--muted); padding: 80px 0; }
.footer {
  max-width: 1060px; margin: 0 auto; padding: 18px; color: var(--muted);
  font-size: 12.5px; border-top: 1px solid var(--line); text-align: center;
}
.muted { color: var(--muted); }
.small { font-size: 13px; }

/* ---------- 卡片与标题 ---------- */
.card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px 20px; margin-bottom: 16px;
}
h1.page-title { font-size: 24px; margin: 6px 0 4px; }
.page-sub { color: var(--muted); margin: 0 0 18px; font-size: 14px; }
h2 { font-size: 19px; margin: 0 0 10px; }
h3 { font-size: 16.5px; margin: 18px 0 8px; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-block; border: none; cursor: pointer; text-decoration: none;
  background: var(--blue); color: #fff; font-size: 14.5px; font-weight: 600;
  padding: 8px 18px; border-radius: 9px; transition: .15s; font-family: var(--sans);
}
.btn:hover { background: var(--blue-dark); }
.btn-ghost { background: #eef3f8; color: var(--blue-dark); }
.btn-ghost:hover { background: #e0eaf4; }
.btn-green { background: var(--green); }
.btn-green:hover { background: #24844b; }
.btn-danger { background: var(--red); }
.btn-sm { padding: 4px 12px; font-size: 13px; }
.btn[disabled] { opacity: .45; cursor: not-allowed; }

/* ---------- 首页 Hero ---------- */
.hero {
  display: flex; gap: 18px; align-items: stretch; flex-wrap: wrap; margin-bottom: 18px;
}
.hero-main {
  flex: 2 1 380px; background: linear-gradient(135deg, var(--blue-dark) 0%, var(--blue) 70%, #4a86b8 100%);
  color: #fff; border-radius: var(--radius); padding: 24px 26px; position: relative; overflow: hidden;
}
.hero-main::after {
  content: "🐍"; position: absolute; right: -10px; bottom: -30px; font-size: 130px; opacity: .12;
}
.hero-main h1 { margin: 0 0 6px; font-size: 26px; }
.hero-main p { margin: 0; opacity: .92; font-size: 14.5px; max-width: 46ch; }
.hero-count {
  flex: 1 1 220px; background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 20px; text-align: center;
}
.hero-count .num { font-size: 42px; font-weight: 800; color: var(--blue-dark); line-height: 1.2; }
.hero-count .lbl { color: var(--muted); font-size: 13px; }
.hero-count .date { color: var(--amber); font-size: 13px; margin-top: 4px; }

/* ---------- 总进度条 ---------- */
.progressbar { height: 12px; background: #e6ecf3; border-radius: 999px; overflow: hidden; }
.progressbar > div {
  height: 100%; border-radius: 999px;
  background: repeating-linear-gradient(45deg, var(--green) 0 12px, #37b268 12px 24px);
  transition: width .4s;
}
.progress-meta { display: flex; justify-content: space-between; font-size: 12.5px; color: var(--muted); margin-top: 5px; }

/* ---------- 关卡地图 ---------- */
.levelmap { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 14px; }
.levelcard {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 16px 18px; position: relative; transition: .15s; display: block; color: inherit; text-decoration: none;
}
.levelcard:hover { transform: translateY(-2px); box-shadow: 0 6px 18px rgba(31,78,121,.12); border-color: #c6d6e6; }
.levelcard .lv-no {
  position: absolute; top: 14px; right: 16px; font-size: 30px; font-weight: 800; color: #edf2f7;
}
.levelcard h3 { margin: 0 0 4px; font-size: 16.5px; color: var(--blue-dark); }
.levelcard .lv-sub { color: var(--muted); font-size: 13px; margin-bottom: 10px; }
.levelcard .lv-stats { display: flex; gap: 14px; font-size: 12.5px; color: var(--muted); }
.levelcard .lv-stats b { color: var(--ink); }
.levelcard.done { border-color: #bfe3cd; background: linear-gradient(180deg, #f2fbf5, #fff); }
.levelcard.done::before {
  content: "✓ 已通关"; position: absolute; top: -9px; left: 14px; background: var(--green);
  color: #fff; font-size: 11.5px; padding: 2px 10px; border-radius: 999px; font-weight: 600;
}
.badge {
  display: inline-block; font-size: 11.5px; padding: 1px 8px; border-radius: 6px;
  background: #eef3f8; color: var(--blue-dark); margin-right: 6px; font-weight: 600;
}
.badge-know { background: #e8f1fb; color: #23538f; }
.badge-master { background: var(--amber-bg); color: var(--amber); }

/* ---------- 关卡页 Tabs ---------- */
.tabs { display: flex; gap: 6px; border-bottom: 2px solid var(--line); margin: 14px 0 16px; flex-wrap: wrap; }
.tabs a {
  padding: 8px 16px; text-decoration: none; color: var(--muted); font-weight: 600; font-size: 14.5px;
  border-radius: 8px 8px 0 0; border-bottom: 2px solid transparent; margin-bottom: -2px;
}
.tabs a.active { color: var(--blue-dark); border-bottom-color: var(--blue); }
.tabs a .done-tick { color: var(--green); }

/* ---------- 课程正文 ---------- */
.lesson h3 { color: var(--blue-dark); border-left: 4px solid var(--yellow); padding-left: 10px; margin-top: 26px; }
.lesson table { border-collapse: collapse; width: 100%; margin: 10px 0; font-size: 14px; }
.lesson th, .lesson td { border: 1px solid var(--line); padding: 6px 10px; text-align: left; vertical-align: top; }
.lesson th { background: #f0f5fa; }
.lesson code, .inline-code {
  font-family: var(--mono); font-size: .92em; background: #eef2f7;
  padding: 1.5px 6px; border-radius: 5px; color: #b3382e;
}
.lesson pre, pre.codeblock {
  background: #10192a; color: #dbe7f5; padding: 14px 16px; border-radius: 10px;
  overflow-x: auto; font-family: var(--mono); font-size: 13.5px; line-height: 1.55; margin: 10px 0;
}
.lesson pre code { background: none; color: inherit; padding: 0; }
.blank-slot { background: #f7c948; color: #10192a; font-weight: 700; padding: 0 4px; border-radius: 4px; }
.keypoints { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 10px; }
.keypoint {
  background: var(--amber-bg); border: 1px solid #f2dfae; border-radius: 10px; padding: 10px 14px; font-size: 13.5px;
}
.keypoint b { color: var(--amber); }
.pitfall {
  background: var(--red-bg); border: 1px solid #f2c9c7; border-radius: 10px;
  padding: 10px 14px; margin: 8px 0; font-size: 13.5px;
}
.pitfall b { color: var(--red); }
.tip {
  background: var(--green-bg); border: 1px solid #bfe3cd; border-radius: 10px;
  padding: 10px 14px; margin: 8px 0; font-size: 13.5px;
}

/* ---------- 题目卡片 ---------- */
.qcard {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px 20px; margin-bottom: 14px;
}
.qcard .qhead { display: flex; justify-content: space-between; align-items: baseline; gap: 10px; margin-bottom: 8px; }
.qcard .qno { font-weight: 700; color: var(--blue-dark); }
.qtag { font-size: 11.5px; background: #eef3f8; color: var(--blue-dark); padding: 2px 9px; border-radius: 999px; white-space: nowrap; }
.qtext { margin: 6px 0 12px; white-space: pre-wrap; }
.opts { display: grid; gap: 8px; }
.opt {
  display: flex; gap: 10px; align-items: flex-start; padding: 9px 13px;
  border: 1.5px solid var(--line); border-radius: 9px; cursor: pointer; transition: .12s; font-size: 14.5px;
}
.opt:hover { border-color: var(--blue); background: #f4f9ff; }
.opt .opt-key { font-weight: 700; color: var(--blue-dark); }
.opt.selected { border-color: var(--blue); background: #eaf3fd; }
.opt.right { border-color: var(--green); background: var(--green-bg); }
.opt.wrong { border-color: var(--red); background: var(--red-bg); }
.opt.disabled { cursor: default; opacity: .9; }
.explain {
  margin-top: 10px; padding: 10px 14px; border-radius: 9px; font-size: 13.5px; background: #f4f7fb;
  border-left: 4px solid var(--blue);
}
.verdict { font-weight: 700; }
.verdict.ok { color: var(--green); }
.verdict.no { color: var(--red); }

/* ---------- 代码区 ---------- */
.editor-wrap { margin: 10px 0; }
textarea.code-editor {
  width: 100%; min-height: 180px; background: #10192a; color: #dbe7f5;
  font-family: var(--mono); font-size: 13.5px; line-height: 1.55; padding: 14px 16px;
  border: 1.5px solid #26344d; border-radius: 10px; resize: vertical; tab-size: 4; outline: none;
}
textarea.code-editor:focus { border-color: var(--blue); }
.io-label { font-size: 12.5px; color: var(--muted); margin: 8px 0 4px; font-weight: 600; }
pre.output {
  background: #0d1522; color: #cfe3d8; padding: 12px 15px; border-radius: 10px;
  font-family: var(--mono); font-size: 13px; min-height: 20px; white-space: pre-wrap;
  word-break: break-all; margin: 4px 0 0;
}
pre.output .out-err { color: #ff9d97; }
.diff-line-add { background: #123b25; display: block; }
.diff-line-del { background: #4a1613; display: block; }
.canvas-box { background: #fff; border: 1px solid var(--line); border-radius: 10px; margin-top: 8px; }

/* ---------- 判定结果 ---------- */
.result-banner {
  border-radius: 10px; padding: 12px 16px; margin-top: 12px; font-size: 14.5px; font-weight: 600;
}
.result-banner.pass { background: var(--green-bg); border: 1px solid #bfe3cd; color: #1d6b3c; }
.result-banner.fail { background: var(--red-bg); border: 1px solid #f2c9c7; color: #96261f; }
.testtable { width: 100%; border-collapse: collapse; font-size: 13px; margin-top: 10px; }
.testtable th, .testtable td { border: 1px solid var(--line); padding: 6px 9px; text-align: left; vertical-align: top; }
.testtable th { background: #f0f5fa; }
.testtable .pass-cell { color: var(--green); font-weight: 700; }
.testtable .fail-cell { color: var(--red); font-weight: 700; }

/* ---------- 模拟考 ---------- */
.mock-timer {
  position: sticky; top: 96px; z-index: 30; display: flex; justify-content: space-between; align-items: center;
  background: #14243b; color: #fff; border-radius: 10px; padding: 10px 18px; margin-bottom: 16px;
}
.mock-timer .t { font-family: var(--mono); font-size: 22px; font-weight: 700; letter-spacing: 1px; }
.mock-timer.urgent .t { color: #ff9d97; animation: blink 1s infinite; }
@keyframes blink { 50% { opacity: .55; } }
.sec-tabs { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 14px; }
.sec-tab {
  padding: 6px 14px; border-radius: 999px; background: #eef3f8; color: var(--blue-dark);
  font-size: 13.5px; font-weight: 600; cursor: pointer; border: 1.5px solid transparent;
}
.sec-tab.active { background: var(--blue); color: #fff; }
.sec-tab .flag { color: var(--red); }
.score-hero { text-align: center; padding: 26px; }
.score-hero .big { font-size: 52px; font-weight: 800; color: var(--blue-dark); }
.grade-tag { display: inline-block; padding: 4px 18px; border-radius: 999px; font-weight: 700; margin: 8px 0; }
.grade-tag.pass { background: var(--green-bg); color: #1d6b3c; border: 1.5px solid #9fd8b4; }
.grade-tag.fail { background: var(--red-bg); color: #96261f; border: 1.5px solid #efb9b5; }

/* ---------- 资源 / 计划 ---------- */
.res-list { display: grid; gap: 10px; }
.res-item {
  display: flex; gap: 12px; align-items: flex-start; background: var(--card);
  border: 1px solid var(--line); border-radius: 10px; padding: 12px 16px; text-decoration: none; color: inherit;
}
.res-item:hover { border-color: var(--blue); }
.res-item .res-ico { font-size: 20px; }
.res-item b { color: var(--blue-dark); }
.res-item .res-desc { color: var(--muted); font-size: 13px; }
.plan-week { display: flex; gap: 12px; margin-bottom: 10px; }
.plan-week .wk {
  flex: 0 0 92px; text-align: center; background: var(--blue); color: #fff; border-radius: 10px;
  padding: 10px 6px; font-weight: 700; font-size: 13.5px; align-self: flex-start;
}
.plan-week .wk small { display: block; font-weight: 400; opacity: .85; font-size: 11.5px; }
.plan-week .wk-body { flex: 1; background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 12px 16px; font-size: 14px; }
.plan-week .wk-body b { color: var(--blue-dark); }

/* ---------- 杂项 ---------- */
.notice {
  background: var(--amber-bg); border: 1px solid #f2dfae; border-radius: 10px;
  padding: 12px 16px; font-size: 13.5px; margin: 12px 0;
}
.notice b { color: var(--amber); }
.stat-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 12px; margin: 14px 0; }
.stat-box { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 14px; text-align: center; }
.stat-box .v { font-size: 24px; font-weight: 800; color: var(--blue-dark); }
.stat-box .k { font-size: 12.5px; color: var(--muted); }
.pagination { display: flex; justify-content: space-between; margin-top: 16px; gap: 10px; }
mark { background: #fff3bf; padding: 0 3px; border-radius: 3px; }
kbd {
  font-family: var(--mono); font-size: .85em; background: #eef2f7; border: 1px solid #d5dde7;
  border-bottom-width: 2px; border-radius: 5px; padding: 1px 6px;
}

@media (max-width: 640px) {
  .brand-sub { display: none; }
  .hero-count { flex-basis: 100%; }
  #app { padding: 14px 12px 50px; }
}