:root {
  --bg: #f4f6fb;
  --card: #ffffff;
  --ink: #1f2937;
  --muted: #6b7280;
  --line: #e5e7eb;
  --brand: #4f46e5;
  --brand2: #0ea5e9;
  --ok: #16a34a;
  --ok-bg: #ecfdf5;
  --bad: #dc2626;
  --bad-bg: #fef2f2;
  --surface: #f8fafc;
  --surface-2: #f1f5f9;
  --opt-bg: #ffffff;
  --opt-hover: #f5f7ff;
  --input-bg: #ffffff;
  --inline-bg: #eef2ff;
  --inline-ink: #3730a3;
  --progress-bg: #e9edf5;
  --hint-bg: #fffbeb;
  --hint-line: #f59e0b;
  --hint-ink: #78350f;
  --code-bg: #0f172a;
  --code-ink: #e2e8f0;
  --shadow: 0 1px 2px rgba(16, 24, 40, 0.04), 0 8px 24px rgba(16, 24, 40, 0.06);
}

[data-theme="dark"] {
  --bg: #0b1120;
  --card: #111a2e;
  --ink: #e5e9f0;
  --muted: #94a3b8;
  --line: #26324a;
  --brand: #818cf8;
  --brand2: #38bdf8;
  --ok: #4ade80;
  --ok-bg: #0c2f22;
  --bad: #f87171;
  --bad-bg: #3a1418;
  --surface: #16213a;
  --surface-2: #1b2743;
  --opt-bg: #16213a;
  --opt-hover: #1e293b;
  --input-bg: #16213a;
  --inline-bg: #1e293b;
  --inline-ink: #a5b4fc;
  --progress-bg: #1e293b;
  --hint-bg: #2a2410;
  --hint-line: #a16207;
  --hint-ink: #fde68a;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 8px 24px rgba(0, 0, 0, 0.35);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "PingFang TC", "Microsoft JhengHei", "Noto Sans TC", "Heiti TC", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  transition: background 0.2s ease, color 0.2s ease;
}

/* 頁首 */
.site-header {
  background: linear-gradient(120deg, #4f46e5, #0ea5e9);
  color: #fff;
  box-shadow: 0 2px 12px rgba(79, 70, 229, 0.25);
  position: sticky;
  top: 0;
  z-index: 20;
}
.site-header .inner {
  max-width: 940px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.brand { color: #fff; text-decoration: none; font-weight: 700; font-size: 1.1rem; letter-spacing: 0.3px; }
.brand .logo { font-size: 1.35rem; margin-right: 6px; }
.nav { display: flex; gap: 8px; align-items: center; }
.nav a {
  color: #eef2ff;
  text-decoration: none;
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 0.95rem;
  transition: background 0.15s ease;
}
.nav a:hover { background: rgba(255, 255, 255, 0.18); }
.theme-toggle,
.lang-toggle {
  background: rgba(255, 255, 255, 0.16);
  border: none;
  color: #fff;
  width: 36px;
  height: 36px;
  border-radius: 999px;
  font-size: 1.05rem;
  line-height: 1;
  cursor: pointer;
  transition: background 0.15s ease;
}
.theme-toggle:hover,
.lang-toggle:hover { background: rgba(255, 255, 255, 0.3); }
.lang-toggle { font-size: 0.9rem; font-weight: 700; }

/* 版面 */
.container { max-width: 940px; margin: 0 auto; padding: 26px 20px 80px; }
.lead { color: var(--muted); font-size: 1.05rem; margin-top: -6px; }
.small { font-size: 0.88rem; }
.muted { color: var(--muted); }
.hidden { display: none !important; }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 22px 24px;
  margin: 18px 0;
  box-shadow: var(--shadow);
}
.card > h2 { margin-top: 0; font-size: 1.25rem; }

/* 首頁 */
.hero {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 28px;
  box-shadow: var(--shadow);
  margin-bottom: 22px;
}
.hero h1 { margin: 0 0 6px; font-size: 1.8rem; }
.overall { margin: 20px 0 6px; }
.hero-actions, .quiz-actions { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 16px; }

.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 16px; }
.module-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 20px;
  text-decoration: none;
  color: inherit;
  box-shadow: var(--shadow);
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}
.module-card:hover { transform: translateY(-3px); box-shadow: 0 12px 30px rgba(16, 24, 40, 0.12); border-color: var(--brand); }
.mc-top { display: flex; align-items: center; gap: 10px; }
.mc-top h3 { margin: 0; font-size: 1.12rem; }
.mc-emoji { font-size: 1.5rem; }
.mc-desc { color: var(--muted); font-size: 0.92rem; margin: 8px 0 14px; min-height: 2.8em; }
.mc-foot { display: flex; justify-content: space-between; align-items: center; margin-top: 8px; font-size: 0.88rem; }
.mc-foot .go { color: var(--brand); font-weight: 600; }

.progress { height: 8px; background: var(--progress-bg); border-radius: 999px; overflow: hidden; }
.progress.big { height: 12px; }
.progress .bar {
  height: 100%;
  width: 0;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--brand), var(--brand2));
  transition: width 0.4s ease;
}

.crumb { margin: 4px 0 10px; }
.crumb a { color: var(--brand); text-decoration: none; font-size: 0.95rem; }
.module-head h1 { margin: 0 0 4px; font-size: 1.65rem; }
.module-progress { margin-top: 14px; }

/* 筆記與範例 */
.note { padding: 6px 0 14px; border-bottom: 1px dashed var(--line); }
.note:last-child { border-bottom: none; }
.note h3 { margin: 12px 0 8px; font-size: 1.05rem; color: var(--brand); }
.note ul { margin: 0 0 10px; padding-left: 22px; }
.note li { margin: 3px 0; }

.example { padding: 6px 0 14px; border-bottom: 1px dashed var(--line); }
.example:last-child { border-bottom: none; }
.example h4 { margin: 10px 0 8px; font-size: 1rem; }
.example .explain {
  font-size: 0.92rem;
  color: var(--ink);
  background: var(--surface);
  border-left: 3px solid var(--brand2);
  padding: 6px 12px;
  border-radius: 0 8px 8px 0;
}

code {
  background: var(--inline-bg);
  color: var(--inline-ink);
  padding: 1px 6px;
  border-radius: 6px;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.9em;
}

.code-block {
  background: var(--code-bg);
  color: var(--code-ink);
  padding: 14px 16px;
  border-radius: 12px;
  overflow-x: auto;
  margin: 10px 0;
  font-size: 0.92rem;
  line-height: 1.55;
}
.code-block code { background: none; color: inherit; padding: 0; font-size: 1em; }

/* 語法高亮（深色底，兩主題共用） */
.tok-kw { color: #c792ea; font-weight: 600; }
.tok-str { color: #a5e075; }
.tok-num { color: #f78c6c; }
.tok-cm { color: #7f8ea3; font-style: italic; }
.tok-bi { color: #82aaff; }

.shade { margin: 8px 0; }
.shade .lbl, .diff .lbl {
  display: inline-block;
  font-size: 0.78rem;
  color: var(--muted);
  background: var(--surface-2);
  border-radius: 6px;
  padding: 1px 8px;
  margin-bottom: 4px;
}
.shade pre, .diff pre {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 12px;
  margin: 0;
  overflow-x: auto;
  white-space: pre-wrap;
  word-break: break-word;
  font-family: "SFMono-Regular", Consolas, Menlo, monospace;
  font-size: 0.88rem;
}

/* 選擇題 */
.q { padding: 14px 0; border-bottom: 1px dashed var(--line); }
.q:last-child { border-bottom: none; }
.qt { font-weight: 600; margin: 0 0 10px; }
.qno {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 24px;
  height: 24px;
  padding: 0 6px;
  margin-right: 8px;
  border-radius: 8px;
  background: linear-gradient(120deg, var(--brand), var(--brand2));
  color: #fff;
  font-size: 0.82rem;
  vertical-align: middle;
}
.opts { display: grid; gap: 8px; }
.opt {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  text-align: left;
  background: var(--opt-bg);
  border: 1.5px solid var(--line);
  border-radius: 12px;
  padding: 10px 14px;
  font: inherit;
  color: inherit;
  cursor: pointer;
  transition: border-color 0.12s ease, background 0.12s ease, transform 0.08s ease;
}
.opt:hover:not(:disabled) { border-color: var(--brand); background: var(--opt-hover); }
.opt:disabled { cursor: default; opacity: 1; }
.opt .mark {
  flex: none;
  width: 24px; height: 24px;
  display: inline-flex; align-items: center; justify-content: center;
  border-radius: 7px;
  background: var(--surface-2);
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--muted);
}
.opt.correct { border-color: var(--ok); background: var(--ok-bg); }
.opt.correct .mark { background: var(--ok); color: #fff; }
.opt.wrong { border-color: var(--bad); background: var(--bad-bg); }
.opt.wrong .mark { background: var(--bad); color: #fff; }
.explain {
  margin-top: 10px;
  background: var(--surface);
  border-left: 3px solid var(--brand2);
  padding: 8px 14px;
  border-radius: 0 8px 8px 0;
  font-size: 0.94rem;
}

/* 填充題 */
.fill-row { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; margin-top: 4px; }
.fill-input {
  flex: 1 1 200px;
  min-width: 160px;
  padding: 10px 12px;
  border: 1.5px solid var(--line);
  border-radius: 10px;
  background: var(--input-bg);
  color: var(--ink);
  font: inherit;
}
.fill-input:focus { outline: 2px solid var(--brand2); outline-offset: 1px; }
.fill-status { font-size: 0.9rem; font-weight: 600; }
.fill-status.ok { color: var(--ok); }
.fill-status.bad { color: var(--bad); }

/* 程式練習 */
.task { padding: 16px 0; border-bottom: 1px dashed var(--line); }
.task:last-child { border-bottom: none; }
.task h4 { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin: 4px 0 8px; font-size: 1.02rem; }
.prompt { background: var(--surface); border-radius: 10px; padding: 10px 14px; margin: 6px 0 10px; font-size: 0.95rem; }

.editor-wrap { position: relative; }
.editor-wrap .editor-highlight,
.editor-wrap .code-editor {
  margin: 0;
  padding: 14px;
  border: 1px solid #1e293b;
  border-radius: 12px;
  font-family: "SFMono-Regular", Consolas, Menlo, monospace;
  font-size: 0.92rem;
  line-height: 1.6;
  tab-size: 4;
  white-space: pre-wrap;
  overflow-wrap: break-word;
  word-break: break-word;
}
.editor-wrap .editor-highlight {
  position: absolute;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
  background: var(--code-bg);
  color: var(--code-ink);
}
.editor-wrap .code-editor {
  position: relative;
  z-index: 1;
  width: 100%;
  min-height: 180px;
  resize: vertical;
  background: transparent;
  color: transparent;
  caret-color: var(--code-ink);
}
.editor-wrap .code-editor::selection { background: rgba(99, 102, 241, 0.45); }
.editor-wrap .code-editor:focus { outline: 2px solid var(--brand2); outline-offset: 1px; }

.task-actions { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-top: 10px; }
.run-status { font-size: 0.88rem; }
.run-status.ok { color: var(--ok); font-weight: 600; }
.run-status.bad { color: var(--bad); font-weight: 600; }
.hint, .solution { margin-top: 10px; }
.hint {
  background: var(--hint-bg);
  color: var(--hint-ink);
  border-left: 3px solid var(--hint-line);
  padding: 8px 14px;
  border-radius: 0 8px 8px 0;
  font-size: 0.94rem;
}
.badge {
  margin-left: 4px;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--ok);
  background: var(--ok-bg);
  border: 1px solid var(--ok);
  border-radius: 999px;
  padding: 1px 10px;
}
.tag-debug {
  margin-left: 4px;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--hint-ink);
  background: var(--hint-bg);
  border: 1px solid var(--hint-line);
  border-radius: 999px;
  padding: 1px 10px;
}
.results { margin-top: 12px; display: grid; gap: 8px; }
.result { border-radius: 10px; padding: 10px 14px; font-size: 0.92rem; }
.result.pass { background: var(--ok-bg); color: var(--ok); border: 1px solid var(--ok); }
.result.fail { background: var(--bad-bg); color: var(--bad); border: 1px solid var(--bad); }
.result pre { margin: 6px 0 0; white-space: pre-wrap; word-break: break-word; font-size: 0.85rem; color: var(--ink); }
.diff { display: grid; gap: 10px; grid-template-columns: 1fr; margin-top: 8px; }
@media (min-width: 640px) { .diff { grid-template-columns: 1fr 1fr; } }

/* 按鈕 */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  border: 1.5px solid transparent;
  border-radius: 11px;
  padding: 9px 16px;
  font: inherit;
  font-size: 0.95rem;
  cursor: pointer;
  text-decoration: none;
  transition: filter 0.12s ease, background 0.12s ease, transform 0.08s ease;
}
.btn:active { transform: scale(0.98); }
.btn.primary { background: linear-gradient(120deg, #4f46e5, #0ea5e9); color: #fff; }
.btn.primary:hover { filter: brightness(1.06); }
.btn.primary:disabled { opacity: 0.6; cursor: progress; }
.btn.ghost { background: var(--card); border-color: var(--line); color: var(--ink); }
.btn.ghost:hover { border-color: var(--brand); color: var(--brand); }
.btn.big { padding: 12px 22px; font-size: 1.02rem; font-weight: 600; }

/* 綜合測驗 */
.quiz h2 { margin: 14px 0 4px; font-size: 1.2rem; line-height: 1.6; }
.quiz-top { display: flex; justify-content: space-between; gap: 10px; }
.pill { background: var(--inline-bg); color: var(--inline-ink); border-radius: 999px; padding: 3px 14px; font-size: 0.85rem; font-weight: 600; }
.pill.alt { background: var(--surface-2); color: var(--brand2); }
.result-card { text-align: center; padding: 44px 24px; }
.result-card h1 { margin: 0; }
.score {
  font-size: 3rem;
  font-weight: 800;
  margin: 12px 0 4px;
  background: linear-gradient(120deg, var(--brand), var(--brand2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.result-card .hero-actions { justify-content: center; }

.about ol { padding-left: 22px; }
.about li { margin: 6px 0; }

.site-footer { text-align: center; color: var(--muted); font-size: 0.85rem; padding: 24px 20px 40px; }