:root {
  --bg: #fbfaf8;
  --surface: #ffffff;
  --fg: #1c1a17;
  --muted: #6b655d;
  --accent: #b8873a;
  --line: #e6e1d8;
  --shadow: 0 1px 3px rgba(28, 26, 23, 0.06), 0 8px 24px rgba(28, 26, 23, 0.04);
  --radius: 10px;
  --content: 44rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #161513;
    --surface: #1e1c1a;
    --fg: #f0ece5;
    --muted: #9c958a;
    --accent: #d9a85f;
    --line: #2e2b27;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.4), 0 8px 24px rgba(0, 0, 0, 0.24);
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: "Noto Sans TC", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang TC",
    "Helvetica Neue", sans-serif;
  font-size: 1.15rem;
  line-height: 2;
  -webkit-font-smoothing: antialiased;
  overflow-wrap: break-word;
}

img { max-width: 100%; height: auto; display: block; }

a { color: inherit; }

.wrap {
  max-width: var(--content);
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* ---------- site header ---------- */

.site-head {
  padding: 3.5rem 0 2rem;
}

.brand {
  display: inline-block;
  font-size: 0.72rem;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 700;
  text-decoration: none;
  margin-bottom: 0.9rem;
}

.site-title {
  font-size: clamp(1.9rem, 7vw, 2.6rem);
  line-height: 1.25;
  margin: 0 0 0.6rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.site-tagline {
  color: var(--muted);
  margin: 0;
  font-size: 1rem;
}

/* ---------- hero ---------- */

.hero {
  margin: 2rem 0 3rem;
}

.hero img {
  width: 100%;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.hero figcaption {
  margin-top: 0.7rem;
  font-size: 0.8rem;
  color: var(--muted);
}

/* ---------- article cards ---------- */

.section-label {
  font-size: 0.72rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 700;
  margin: 0 0 1.2rem;
}

.cards {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.card:hover { border-color: var(--accent); }

.card a {
  display: block;
  padding: 1.35rem 1.5rem;
  text-decoration: none;
  color: inherit;
}

.card h2 {
  margin: 0 0 0.45rem;
  font-size: 1.15rem;
  line-height: 1.5;
  font-weight: 600;
}

.card p {
  margin: 0 0 0.8rem;
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.7;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  font-size: 0.78rem;
  color: var(--muted);
  align-items: center;
}

.meta time { white-space: nowrap; }

.meta .dot { opacity: 0.4; }

/* ---------- article page ---------- */

.post-head { padding: 3rem 0 0; }

.back {
  display: inline-block;
  font-size: 0.85rem;
  color: var(--muted);
  text-decoration: none;
  margin-bottom: 2rem;
}

.back:hover { color: var(--accent); }

.post-title {
  font-size: clamp(1.6rem, 5.5vw, 2.2rem);
  line-height: 1.4;
  margin: 0 0 0.9rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.post-body { padding-bottom: 1rem; }

.post-body h2 {
  font-size: 1.2rem;
  font-weight: 600;
  margin: 2.6rem 0 0.8rem;
  line-height: 1.6;
}

.post-body h3 {
  font-size: 1.03rem;
  font-weight: 600;
  margin: 2rem 0 0.6rem;
}

.post-body p { margin: 0 0 1.1rem; }

.post-body ul, .post-body ol { margin: 0 0 1.2rem; padding-left: 1.4rem; }

.post-body li { margin-bottom: 0.45rem; }

.post-body blockquote {
  margin: 1.6rem 0;
  padding: 0.2rem 0 0.2rem 1.1rem;
  border-left: 3px solid var(--accent);
  color: var(--muted);
}

.post-body figure { margin: 2rem 0; }

.post-body figure img {
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.post-body figcaption {
  margin-top: 0.7rem;
  font-size: 0.8rem;
  color: var(--muted);
}

hr {
  border: 0;
  border-top: 1px solid var(--line);
  margin: 3rem 0;
}

/* ---------- footer ---------- */

.site-foot {
  margin-top: 4rem;
  padding: 1.8rem 0 3rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.9;
}

.site-foot p { margin: 0 0 0.3rem; }

.site-foot a { color: var(--muted); }

.site-foot a:hover { color: var(--accent); }

@media (max-width: 480px) {
  .site-head { padding-top: 2.5rem; }
  .card a { padding: 1.15rem 1.2rem; }
}

/* ---------- 內文圖表 ---------- */

.diagram {
  margin: 2.2rem 0;
}

.diagram svg {
  display: block;
  width: 100%;
  height: auto;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.diagram figcaption {
  margin-top: 0.7rem;
  font-size: 0.8rem;
  color: var(--muted);
}

/* 圖表內的文字與線條顏色，跟著深淺色模式走 */
.d-fg { fill: var(--fg); }
.d-muted { fill: var(--muted); }
.d-accent { fill: var(--accent); }
.d-line { stroke: var(--line); }
.d-bar { fill: var(--accent); opacity: 0.85; }
.d-bar-soft { fill: var(--accent); opacity: 0.35; }

/* ---------- 參考文獻 ---------- */

.refs {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
  font-size: 0.82rem;
  line-height: 1.75;
  color: var(--muted);
}

.refs h2 {
  font-size: 0.95rem;
  color: var(--fg);
  margin: 0 0 0.9rem;
}

.refs ol { padding-left: 1.3rem; margin: 0; }

.refs li { margin-bottom: 0.5rem; }

/* ---------- 互動補給計算器 ---------- */

.fuel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.4rem 1.4rem 1.2rem;
  margin: 2.2rem 0;
}

.fuel-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin: 0 0 0.3rem;
}

.fuel-lede {
  font-size: 0.86rem;
  color: var(--muted);
  margin: 0 0 1.3rem;
  line-height: 1.7;
}

.fuel-q { margin-bottom: 1.1rem; }

.fuel-q > span {
  display: block;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--muted);
  margin-bottom: 0.5rem;
}

.chips { display: flex; flex-wrap: wrap; gap: 0.45rem; }

.chip {
  font: inherit;
  font-size: 0.86rem;
  line-height: 1.3;
  padding: 0.5rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: transparent;
  color: var(--fg);
  cursor: pointer;
  transition: border-color 0.12s ease, background 0.12s ease;
}

.chip:hover { border-color: var(--accent); }

.chip[aria-pressed="true"] {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
  font-weight: 600;
}

.fuel-out {
  margin-top: 1.4rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--line);
}

.fuel-row {
  display: flex;
  gap: 0.9rem;
  padding: 0.55rem 0;
  align-items: baseline;
}

.fuel-row dt {
  flex: 0 0 5.2rem;
  font-size: 0.82rem;
  color: var(--muted);
  font-weight: 600;
}

.fuel-row dd {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.65;
}

.fuel-row dd b { color: var(--accent); font-size: 1.05rem; }

.fuel-row dd small {
  display: block;
  font-size: 0.8rem;
  color: var(--muted);
  margin-top: 0.1rem;
}

.fuel-note {
  margin: 1rem 0 0;
  font-size: 0.78rem;
  color: var(--muted);
  line-height: 1.7;
}

@media (max-width: 420px) {
  .fuel-row { display: block; }
  .fuel-row dt { margin-bottom: 0.1rem; }
}

/* ---------- 常見問答 ---------- */

.qa { margin: 2rem 0 1rem; }

.qa details {
  border-bottom: 1px solid var(--line);
}

.qa details[open] summary { color: var(--accent); }

.qa summary {
  cursor: pointer;
  padding: 0.85rem 0;
  font-size: 0.98rem;
  font-weight: 600;
  line-height: 1.6;
  list-style: none;
  display: flex;
  gap: 0.6rem;
  align-items: baseline;
}

.qa summary::-webkit-details-marker { display: none; }

.qa summary::before {
  content: "＋";
  color: var(--accent);
  font-weight: 700;
  flex: 0 0 auto;
}

.qa details[open] summary::before { content: "－"; }

.qa .qa-body {
  padding: 0 0 1rem 1.5rem;
  font-size: 0.93rem;
  line-height: 1.8;
  color: var(--muted);
}

.qa .qa-body p { margin: 0 0 0.6rem; }

.qa .qa-body p:last-child { margin-bottom: 0; }