/* ---------- tokens ---------- */
:root {
  --color-canvas: #f7f8fa;
  --color-container: #ffffff;
  --color-surface: #f2f4f7;
  --color-surface-selected: #eef4ff;
  --color-text: #16202e;
  --color-text-muted: #64707f;
  --color-border: #e3e7ec;
  --color-border-strong: #cfd6de;
  --color-accent: #3b6fd4;
  --color-accent-hover: #2f5bb0;
  --color-on-accent: #ffffff;

  --c-base: #64707f;
  --c-c1: #3b6fd4;
  --c-c2a: #c2622f;
  --c-c2b: #8a5bbf;
  --c-cached: #8fa6c4;
  --c-uncached: #3b6fd4;
  --c-output: #c2622f;

  --sidebar-width: 236px;
  --content-max: 1180px;
  --head-primary-h: 62px;
  --head-secondary-h: 48px;

  --space-1: .25rem; --space-2: .5rem; --space-3: .75rem; --space-4: 1rem;
  --space-5: 1.25rem; --space-6: 1.5rem; --space-8: 2rem; --space-12: 3rem;

  --radius-sm: 6px; --radius-md: 10px; --radius-lg: 14px;

  --fs-caption: .8125rem;
  --fs-nav2: .875rem;
  --fs-body: .9375rem;
  --fs-heading: 1.0625rem;
  --fs-section: 1.3125rem;
  --fs-metric: 1.75rem;
}

:root[data-theme="dark"] {
  --color-canvas: #0b0d10;
  --color-container: #000000;
  --color-surface: #16191e;
  --color-surface-selected: #16233b;
  --color-text: #e7ebf0;
  --color-text-muted: #98a2b0;
  --color-border: #232830;
  --color-border-strong: #333a45;
  --color-accent: #6b9bff;
  --color-accent-hover: #86afff;
  --color-on-accent: #07101f;

  --c-base: #98a2b0;
  --c-c1: #6b9bff;
  --c-c2a: #e2894f;
  --c-c2b: #b48ae0;
  --c-cached: #6d829c;
  --c-uncached: #6b9bff;
  --c-output: #e2894f;
}

/* Web Awesome remap (unlayered so it wins over the theme's layered rules) */
:root, :root[data-theme="dark"] {
  --wa-form-control-background-color: var(--color-container);
  --wa-form-control-border-color: var(--color-border-strong);
  --wa-form-control-activated-color: var(--color-accent);
  --wa-color-surface-default: var(--color-container);
  --wa-color-surface-raised: var(--color-container);
  --wa-color-surface-border: var(--color-border);
  --wa-color-neutral-fill-quiet: var(--color-surface);
  --wa-color-text-normal: var(--color-text);
  --wa-color-text-quiet: var(--color-text-muted);
  --wa-color-text-link: var(--color-accent);
}
wa-option::part(base) { color: var(--color-text); }
wa-option { --current-text-color: var(--color-text); }

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--color-canvas);
  color: var(--color-text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC",
               "PingFang TC", "Microsoft JhengHei", Roboto, sans-serif;
  font-size: var(--fs-body);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
:focus-visible { outline: 2px solid var(--color-accent); outline-offset: 2px; }
.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--color-container); padding: var(--space-2) var(--space-4);
  border: 1px solid var(--color-border); border-radius: var(--radius-sm);
}
.skip-link:focus { left: var(--space-4); top: var(--space-4); }

/* ---------- shell ---------- */
.shell { display: flex; min-height: 100vh; }

.sidebar {
  width: var(--sidebar-width); flex: 0 0 var(--sidebar-width);
  position: sticky; top: 0; height: 100vh;
  display: flex; flex-direction: column;
  background: var(--color-canvas);
  border-right: 1px solid var(--color-border);
}
.sidebar-header { padding: var(--space-5) var(--space-4) var(--space-4); }
.sidebar-title { font-size: var(--fs-heading); font-weight: 650; line-height: 1.35; display: block; }
.sidebar-content { flex: 1; overflow-y: auto; padding: 0 var(--space-3); }
.sidebar-footer { padding: var(--space-3) var(--space-4) var(--space-4); }

.nav-list, .nav-list ul { list-style: none; margin: 0; padding: 0; }
.nav-list li { margin: 0; }
.nav-row {
  display: flex; align-items: center; gap: var(--space-1);
  border-radius: var(--radius-sm);
}
.nav-row:has(> .nav-link.is-active),
.nav-row.is-active-ancestor { background: var(--color-surface-selected); }
.nav-link {
  display: block; flex: 1; min-width: 0;
  padding: var(--space-2) var(--space-3);
  color: var(--color-text); text-decoration: none;
  font-size: var(--fs-body); font-weight: 550;
  border-radius: var(--radius-sm);
}
.nav-link.nav-child {
  padding-left: var(--space-6); font-size: var(--fs-nav2);
  font-weight: 450; color: var(--color-text-muted);
}
.nav-link:hover { color: var(--color-accent); }
.nav-link.is-active { color: var(--color-accent); font-weight: 650; }
.nav-chevron {
  height: 26px; width: 26px; align-self: center; flex: 0 0 26px;
  display: grid; place-items: center; margin-right: var(--space-1);
  background: none; border: 0; cursor: pointer; border-radius: var(--radius-sm);
  color: var(--color-text-muted);
}
.nav-chevron svg { width: 15px; height: 15px; min-width: 15px; fill: none; stroke: currentColor; stroke-width: 2; transition: transform .18s ease; }
.nav-chevron[aria-expanded="false"] svg { transform: rotate(-90deg); }
.nav-sub { display: grid; grid-template-rows: 0fr; overflow: hidden; transition: grid-template-rows .2s ease; }
.nav-sub.is-open { grid-template-rows: 1fr; }
.nav-sub > ul { min-height: 0; margin: 0; padding: 0; overflow: visible; }

.theme-toggle {
  width: 32px; height: 32px; border-radius: 50%;
  border: 1px solid var(--color-border-strong); background: var(--color-container);
  color: var(--color-text-muted); cursor: pointer; display: grid; place-items: center;
}
.theme-toggle svg { width: 16px; height: 16px; min-width: 16px; flex: none; fill: none; stroke: currentColor; stroke-width: 1.8; grid-area: 1/1; transition: opacity .18s ease; }
:root[data-theme="light"] .icon-moon, :root[data-theme="dark"] .icon-sun { opacity: 0; }

.drawer-trigger, .backdrop { display: none; }

/* ---------- content ---------- */
.inset { flex: 1; min-width: 0; scroll-padding-top: calc(var(--head-primary-h) + var(--head-secondary-h)); }
.section { max-width: var(--content-max); margin: 0 auto; padding: 0 var(--space-8); }
html { scroll-padding-top: calc(var(--head-primary-h) + var(--head-secondary-h)); scroll-behavior: smooth; }

.sec-head {
  position: sticky; top: 0; z-index: 20;
  background: var(--color-canvas);
  border-bottom: 1px solid var(--color-border);
  min-height: var(--head-primary-h);
  display: flex; align-items: center; justify-content: space-between;
  gap: var(--space-4); flex-wrap: wrap;
  padding: var(--space-3) 0;
}
.sec-head.sub {
  top: var(--head-primary-h); z-index: 15;
  min-height: var(--head-secondary-h); border-bottom: 0;
  padding: var(--space-2) 0;
}
.sec-head h2 { font-size: var(--fs-section); margin: 0; font-weight: 650; }
.sec-head h3 { font-size: var(--fs-heading); margin: 0; font-weight: 600; color: var(--color-text-muted); }
.sec-body { padding: var(--space-5) 0 var(--space-12); }

.head-controls { display: flex; align-items: center; gap: var(--space-4); flex-wrap: wrap; }
.head-controls .ctl { font-size: var(--fs-body); color: var(--color-text-muted); white-space: nowrap; }
.head-controls wa-select { min-width: 220px; }

.lede { margin: 0 0 var(--space-5); color: var(--color-text-muted); max-width: 72ch; }
.note { font-size: var(--fs-caption); color: var(--color-text-muted); margin: var(--space-3) 0 0; max-width: 78ch; }
h4 { font-size: var(--fs-heading); margin: var(--space-6) 0 var(--space-3); font-weight: 600; }
.sec-body > h4:first-child { margin-top: 0; }

.metrics { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: var(--space-3); margin-bottom: var(--space-6); }
.metric {
  border: 1px solid var(--color-border); border-radius: var(--radius-md);
  background: var(--color-container); padding: var(--space-4);
}
.metric .label { font-size: var(--fs-body); color: var(--color-text-muted); display: block; }
.metric .value { font-size: var(--fs-metric); font-weight: 650; line-height: 1.25; display: block; margin-top: var(--space-1); }
.metric .delta { font-size: var(--fs-body); color: var(--color-text-muted); }
.metric .delta.up { color: var(--c-c2a); }

.panel {
  border: 1px solid var(--color-border); border-radius: var(--radius-md);
  background: var(--color-container); padding: var(--space-5);
  margin: 0 0 var(--space-6); overflow: hidden;
}
.panel figcaption h4, .panel > h4 { margin: 0 0 var(--space-4); }
.chart-box { position: relative; height: 320px; }
.chart-box.tall { height: 420px; }

.table-wrap { overflow-x: auto; border: 1px solid var(--color-border); border-radius: var(--radius-md); background: var(--color-container); margin-bottom: var(--space-4); }
table { width: 100%; border-collapse: collapse; font-size: var(--fs-body); }
th, td { padding: var(--space-3) var(--space-4); text-align: right; white-space: nowrap; border-bottom: 1px solid var(--color-border); }
th:first-child, td:first-child { text-align: left; }
thead th { background: var(--color-surface); font-weight: 600; color: var(--color-text-muted); position: sticky; top: 0; }
tbody tr:last-child td { border-bottom: 0; }
tbody tr.is-total td { font-weight: 650; background: var(--color-surface); }
td.num { font-variant-numeric: tabular-nums; }
td .sub { color: var(--color-text-muted); }

.defs { margin: 0; display: grid; gap: var(--space-4); }
.defs dt { font-weight: 650; }
.defs dd { margin: var(--space-1) 0 0; color: var(--color-text-muted); max-width: 80ch; }

.bullets { margin: 0 0 var(--space-4); padding-left: 1.2rem; }
.bullets li { margin-bottom: var(--space-2); max-width: 82ch; }

.info {
  width: 17px; height: 17px; border-radius: 50%; margin-left: var(--space-2);
  border: 1px solid var(--color-border-strong); background: transparent;
  color: var(--color-text-muted); font-size: 11px; line-height: 1; cursor: help;
  display: inline-grid; place-items: center; vertical-align: middle; padding: 0;
}
.tip {
  position: fixed; z-index: 60; max-width: 280px;
  background: var(--color-container); color: var(--color-text);
  border: 1px solid var(--color-border-strong); border-radius: var(--radius-sm);
  padding: var(--space-2) var(--space-3); font-size: var(--fs-caption); line-height: 1.5;
}

.status { max-width: var(--content-max); margin: 0 auto; padding: var(--space-8); color: var(--color-text-muted); }
.status.error { color: var(--c-c2a); }

/* ---------- responsive ---------- */
@media (max-width: 900px) {
  .drawer-trigger {
    display: grid; place-items: center; position: fixed; top: 10px; left: 10px; z-index: 50;
    width: 38px; height: 38px; border-radius: var(--radius-sm);
    border: 1px solid var(--color-border-strong); background: var(--color-container); cursor: pointer;
    color: var(--color-text);
  }
  .drawer-trigger svg { width: 18px; height: 18px; min-width: 18px; fill: none; stroke: currentColor; stroke-width: 2; }
  body.drawer-open .drawer-trigger { left: calc(var(--sidebar-width) + 10px); }
  .sidebar {
    position: fixed; z-index: 45; transform: translateX(-100%);
    transition: transform .2s ease; background: var(--color-canvas);
  }
  body.drawer-open .sidebar { transform: none; }
  .sidebar-header { padding-top: 58px; }
  .backdrop { display: block; position: fixed; inset: 0; z-index: 40; background: rgba(0,0,0,.38); }
  .backdrop[hidden] { display: none; }
  .section { padding: 0 var(--space-4); }
  .sec-head { padding-top: 56px; }
  .sec-head.sub { padding-top: var(--space-2); }
  .head-controls wa-select { min-width: 180px; }
}