/* ============================================================
   Zappale — field-manual edition
   Design language: warm paper, ink serif, one orange accent.
   Fraunces (display) + Inter (text), self-hosted, light only.
   Mobile-first hardened: longhand font props (no clamp-in-
   shorthand for Safari), no body overflow hacks, safe-area
   aware, 44px touch targets, anchor scroll margins.
   ============================================================ */

@font-face {
  font-family: "Fraunces";
  src: url("assets/fonts/fraunces-normal.woff2") format("woff2");
  font-weight: 400 700;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: "Fraunces";
  src: url("assets/fonts/fraunces-italic.woff2") format("woff2");
  font-weight: 400 700;
  font-style: italic;
  font-display: swap;
}
@font-face {
  font-family: "Inter";
  src: url("assets/fonts/inter-normal.woff2") format("woff2");
  font-weight: 400 700;
  font-style: normal;
  font-display: swap;
}

:root {
  --paper: #faf6ef;
  --paper-well: #f3ece0;
  --ink: #201b14;
  --ink-soft: #5c5546;
  --ink-faint: #97907e;
  --accent: #d9531e;
  --accent-deep: #a93f12;
  --accent-wash: rgba(217, 83, 30, 0.1);
  --rule: #e3dac8;
  --rule-strong: #c9bea6;
  --serif: "Fraunces", "Iowan Old Style", "Palatino Linotype", Georgia, serif;
  --sans: "Inter", -apple-system, "SF Pro Text", "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --wrap: 1040px;
  --pad: clamp(20px, 4.5vw, 28px);
  --header-h: 64px;
}

/* ---------- base ---------- */

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  text-rendering: optimizeLegibility;
  -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}

a, button, kbd, .btn, .menu-btn { touch-action: manipulation; }

.container {
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--pad);
  padding-left: max(var(--pad), env(safe-area-inset-left));
  padding-right: max(var(--pad), env(safe-area-inset-right));
}

a { color: inherit; text-decoration: none; }
h1, h2, h3, p, ul, ol, figure { margin: 0; }
ul, ol { padding: 0; list-style: none; }
kbd { font-family: var(--mono); }
img { display: block; max-width: 100%; height: auto; }

section, .chapter, .colophon { scroll-margin-top: calc(var(--header-h) + 16px); }

.text-link { color: var(--accent-deep); text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1px; }
.text-link:hover { text-decoration-thickness: 2px; }

.skip {
  position: absolute; left: -9999px; top: 0; z-index: 99;
  background: var(--ink); color: var(--paper);
  padding: 10px 16px; border-radius: 0 0 6px 0;
}
.skip:focus { left: 0; }

::selection { background: rgba(217, 83, 30, 0.18); }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

/* ---------- reveal ---------- */

.reveal { opacity: 0; transform: translateY(10px); transition: opacity 0.6s ease, transform 0.6s cubic-bezier(0.2, 0.7, 0.2, 1); }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* ---------- masthead ---------- */

.masthead {
  position: sticky; top: 0; z-index: 40;
  background: rgba(250, 246, 239, 0.94);
  -webkit-backdrop-filter: blur(10px); backdrop-filter: blur(10px);
  border-bottom: 3px double var(--rule-strong);
}
.masthead-inner { display: flex; align-items: center; gap: 26px; min-height: var(--header-h); }

.brand { display: inline-flex; align-items: center; gap: 11px; min-height: 44px; }
.brand-key {
  display: grid; place-items: center; width: 28px; height: 28px; flex: none;
  background: var(--accent); color: var(--paper);
  border: 1.5px solid var(--ink); border-radius: 6px;
  font-family: var(--serif); font-style: italic; font-weight: 600; font-size: 16px; line-height: 1;
  box-shadow: 1.5px 1.5px 0 0 var(--ink);
}
.brand-name { font-family: var(--serif); font-weight: 600; font-size: 19px; line-height: 1; letter-spacing: -0.01em; }

.site-nav { margin-left: auto; display: flex; gap: 26px; }
.site-nav a {
  font-family: var(--sans); font-weight: 500; font-size: 14px; line-height: 1;
  color: var(--ink-soft); padding: 12px 0; transition: color 0.15s;
}
.site-nav a:hover {
  color: var(--ink); text-decoration: underline;
  text-underline-offset: 6px; text-decoration-color: var(--accent); text-decoration-thickness: 2px;
}

.masthead-actions { display: flex; align-items: center; gap: 18px; }
.gh-link { font-family: var(--sans); font-weight: 500; font-size: 14px; line-height: 1; color: var(--ink-soft); padding: 12px 0; }
.gh-link:hover { color: var(--ink); }

.menu-btn {
  display: none; margin-left: auto;
  align-items: center; gap: 10px; min-height: 44px; padding: 8px 0;
  background: none; border: 0; cursor: pointer;
  font-family: var(--sans); font-weight: 600; font-size: 13px; line-height: 1;
  letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink);
}
.menu-btn-box { display: grid; gap: 4px; width: 20px; }
.menu-btn-box span { height: 2px; background: var(--ink); border-radius: 1px; transition: transform 0.2s, opacity 0.2s; }
.menu-btn[aria-expanded="true"] .menu-btn-box span:first-child { transform: translateY(6px) rotate(45deg); }
.menu-btn[aria-expanded="true"] .menu-btn-box span:nth-child(2) { opacity: 0; }
.menu-btn[aria-expanded="true"] .menu-btn-box span:last-child { transform: translateY(-6px) rotate(-45deg); }

.mobile-nav { border-top: 1px solid var(--rule); }
.mobile-nav .container { display: grid; gap: 2px; padding-block: 10px 18px; }
.mobile-nav a:not(.btn) {
  display: flex; align-items: center;
  font-family: var(--sans); font-weight: 500; font-size: 16px; line-height: 1.2;
  color: var(--ink); padding: 12px 0; min-height: 44px;
}
.mobile-nav .btn { margin-top: 12px; justify-content: center; }

/* ---------- buttons ---------- */

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 44px; padding: 10px 22px;
  font-family: var(--sans); font-weight: 600; font-size: 14.5px; line-height: 1; letter-spacing: 0.01em;
  border-radius: 6px; border: 1px solid transparent;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s, transform 0.12s;
}
.btn:active { transform: translateY(1px); }
.btn-small { min-height: 38px; padding: 8px 16px; font-size: 13.5px; }
.btn-primary { background: var(--ink); color: var(--paper); }
.btn-primary:hover { background: var(--accent); border-color: var(--accent-deep); }
.btn-ghost { border-color: var(--ink); color: var(--ink); background: transparent; }
.btn-ghost:hover { background: var(--paper-well); }

/* ---------- title page ---------- */

.hero { padding: clamp(44px, 9vw, 96px) 0 0; text-align: center; }

.kicker {
  display: flex; align-items: center; justify-content: center; gap: 16px;
  font-family: var(--sans); font-weight: 600; font-size: 11.5px; line-height: 1;
  letter-spacing: 0.26em; text-transform: uppercase; color: var(--ink-soft);
}
.kicker::before, .kicker::after { content: ""; height: 1px; width: min(72px, 14vw); background: var(--rule-strong); flex: none; }

.hero h1 {
  margin: 24px auto 0; max-width: 12em;
  font-family: var(--serif); font-weight: 580;
  font-size: clamp(33px, 8vw, 68px); line-height: 1.05;
  letter-spacing: -0.012em;
  text-wrap: balance;
}
.hero h1 em { font-style: italic; color: var(--accent); }

.lede {
  margin: 20px auto 0; max-width: 35em;
  font-size: clamp(15px, 2vw, 17.5px); line-height: 1.68; color: var(--ink-soft);
}

.cta-row { margin-top: 30px; display: flex; justify-content: center; gap: 12px; flex-wrap: wrap; }

.plate { margin: clamp(32px, 6vw, 60px) auto 0; max-width: 900px; text-align: left; }
.plate-frame { border: 1px solid var(--rule-strong); padding: clamp(7px, 1.8vw, 14px); }
.plate-frame img { width: 100%; border: 1px solid var(--rule); }
.plate figcaption {
  margin-top: 12px; text-align: center;
  font-family: var(--serif); font-style: italic; font-weight: 400; font-size: 14px; line-height: 1.5;
  color: var(--ink-soft);
}
.fig-no {
  font-family: var(--sans); font-style: normal; font-weight: 600; font-size: 10.5px; line-height: 1;
  letter-spacing: 0.18em; text-transform: uppercase;
  color: var(--ink-faint); margin-right: 9px;
}

/* ---------- chapters ---------- */

.chapter { padding-top: clamp(60px, 11vw, 120px); }

.chapter-head {
  display: flex; align-items: center; gap: 14px;
  font-family: var(--sans); font-weight: 600; font-size: 11px; line-height: 1.2;
  letter-spacing: 0.22em; text-transform: uppercase; color: var(--ink-faint);
}
.chapter-head::after { content: ""; flex: 1; height: 1px; background: var(--rule); }
.chapter-no { color: var(--accent-deep); }

.chapter-title {
  margin-top: 18px; max-width: 17em;
  font-family: var(--serif); font-weight: 600;
  font-size: clamp(26px, 4.4vw, 42px); line-height: 1.12;
  letter-spacing: -0.012em;
  text-wrap: balance;
}
.chapter-intro { margin-top: 14px; max-width: 39em; font-size: clamp(15px, 2vw, 16.5px); line-height: 1.68; color: var(--ink-soft); }

/* ---------- chapter 01: the index ---------- */

.index { margin-top: 40px; border-top: 1px solid var(--rule-strong); }
.index li {
  display: grid; grid-template-columns: 58px 1fr auto; gap: 6px 20px;
  align-items: start; padding: 20px 0;
  border-bottom: 1px solid var(--rule);
}
.ix-no { padding-top: 3px; font-family: var(--mono); font-weight: 500; font-size: 12.5px; line-height: 1.4; color: var(--accent-deep); }
.ix-line { display: flex; align-items: baseline; gap: 12px; min-width: 0; }
.ix-title { font-family: var(--sans); font-weight: 600; font-size: 16px; line-height: 1.35; }
.ix-lead { flex: 1; min-width: 24px; border-bottom: 1px dotted var(--rule-strong); transform: translateY(-4px); }
.ix-tag { padding-top: 3px; font-family: var(--mono); font-weight: 500; font-size: 12px; line-height: 1.4; color: var(--ink-soft); white-space: nowrap; }
.ix-desc { margin-top: 6px; max-width: 46em; font-size: 14.5px; line-height: 1.62; color: var(--ink-soft); }

.index-tail { margin-top: 24px; font-family: var(--serif); font-style: italic; font-weight: 400; font-size: 16px; line-height: 1.65; color: var(--ink-soft); }

/* ---------- chapter 02: principles ---------- */

.principles { margin-top: 44px; display: grid; grid-template-columns: repeat(3, 1fr); gap: 36px 44px; }
.principle { border-top: 2px solid var(--ink); padding-top: 16px; }
.pr-no { font-family: var(--serif); font-style: italic; font-weight: 500; font-size: 30px; line-height: 1; color: var(--accent); }
.principle h3 { margin-top: 12px; font-family: var(--sans); font-weight: 600; font-size: 17px; line-height: 1.3; }
.principle p { margin-top: 8px; font-size: 14.5px; line-height: 1.64; color: var(--ink-soft); }

.fineprint { margin-top: 32px; font-family: var(--serif); font-style: italic; font-weight: 400; font-size: 14px; line-height: 1.6; color: var(--ink-faint); }

/* ---------- chapter 03: keys ---------- */

.keys { margin-top: 44px; max-width: 680px; }
.key-row {
  display: grid; grid-template-columns: 150px 1fr; gap: 8px 24px;
  align-items: center; padding: 15px 0;
  border-bottom: 1px solid var(--rule);
}
.key-row:first-child { border-top: 1px solid var(--rule-strong); }
.keycaps { display: flex; gap: 6px; flex-wrap: wrap; }
kbd {
  min-width: 27px; padding: 5px 9px; text-align: center;
  font-family: var(--mono); font-weight: 500; font-size: 12.5px; line-height: 1.4;
  color: var(--ink); background: var(--paper);
  border: 1px solid var(--ink); border-radius: 5px;
  box-shadow: 2px 2px 0 0 var(--rule-strong);
}
.key-desc { font-size: 15px; line-height: 1.5; color: var(--ink-soft); }

/* ---------- chapter 04: steps ---------- */

.steps { margin-top: 44px; display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px 40px; }
.step { border-top: 2px solid var(--ink); padding-top: 16px; }
.step-n { font-family: var(--sans); font-weight: 600; font-size: 11px; line-height: 1; letter-spacing: 0.2em; text-transform: uppercase; color: var(--accent-deep); }
.step h3 { margin-top: 12px; font-family: var(--sans); font-weight: 600; font-size: 17px; line-height: 1.3; }
.step h3 kbd { margin: 0 1px; }
.step p { margin-top: 8px; font-size: 14.5px; line-height: 1.64; color: var(--ink-soft); }

/* ---------- colophon ---------- */

.colophon {
  margin-top: clamp(72px, 12vw, 132px);
  border-top: 3px double var(--rule-strong);
  padding-top: clamp(48px, 8vw, 80px);
  text-align: center;
}
.fleuron { display: block; color: var(--accent); font-size: 22px; line-height: 1; }
.colophon h2 {
  margin-top: 16px;
  font-family: var(--serif); font-weight: 600;
  font-size: clamp(25px, 4vw, 40px); line-height: 1.15; letter-spacing: -0.012em;
}
.colophon p { margin: 14px auto 0; max-width: 34em; color: var(--ink-soft); font-size: 16px; line-height: 1.65; }
.colophon .cta-row { margin-top: 28px; }

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

.footer { margin-top: clamp(64px, 10vw, 104px); border-top: 1px solid var(--rule-strong); padding: 26px 0 36px; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; gap: 14px 24px; flex-wrap: wrap; }
.footer p { font-family: var(--sans); font-weight: 500; font-size: 12.5px; line-height: 1.5; color: var(--ink-faint); }
.footer-links { display: flex; gap: 20px; flex-wrap: wrap; }
.footer-links a { font-family: var(--sans); font-weight: 500; font-size: 13.5px; line-height: 1; color: var(--ink-soft); padding: 8px 0; }
.footer-links a:hover { color: var(--ink); }

/* ---------- responsive ---------- */

/* 平板与大型手机：索引条目改为两栏网格，§ 编号与标题同行 */
@media (max-width: 720px) {
  :root { --header-h: 58px; }
  .index li {
    grid-template-columns: auto 1fr;
    column-gap: 12px; row-gap: 8px;
    padding: 18px 0;
  }
  .ix-main { display: contents; }
  .ix-no { grid-area: 1 / 1; align-self: center; padding-top: 0; }
  .ix-line { grid-area: 1 / 2; display: flex; align-items: baseline; }
  .ix-tag {
    grid-area: 2 / 2; justify-self: start;
    padding: 3px 9px; margin-top: 2px;
    border: 1px solid var(--rule-strong); border-radius: 4px;
  }
  .ix-desc { grid-area: 3 / 2; margin-top: 0; }
}

@media (max-width: 900px) {
  .principles { grid-template-columns: 1fr; gap: 30px; }
  .steps { grid-template-columns: 1fr; gap: 28px; }
}

@media (max-width: 760px) {
  .site-nav, .masthead-actions { display: none; }
  .menu-btn { display: inline-flex; }
}

@media (max-width: 560px) {
  .key-row { grid-template-columns: 1fr; gap: 10px; }
  .cta-row .btn { width: 100%; }
  .plate figcaption { font-size: 13px; }
  .footer-inner { justify-content: center; text-align: center; }
  .chapter-head { letter-spacing: 0.16em; }
}