/* ══════════════════════════════════════════════════════════════
   base.css — 设计令牌、宣纸底、排版
   所有颜色字号都从这里取，不要在别处硬编码
   ══════════════════════════════════════════════════════════════ */

:root {
  /* 墨 */
  --ink-900: #1c1f1d;
  --ink-700: #333a35;
  --ink-500: #5a625b;
  --ink-300: #8d948a;
  --ink-150: #c3c6bd;

  /* 纸 */
  --paper: #f4efe4;
  --paper-warm: #ece4d3;
  --paper-deep: #ddd2bb;

  /* 点缀 */
  --water: #6d8f8a;
  --bamboo: #7c9160;
  --ochre: #b1813f;
  --cinnabar: #9d3a30;
  --gold: #b8912f;

  /* 字体 */
  --font-serif: "Songti SC", "Source Han Serif SC", "Noto Serif SC", "SimSun", 宋体, serif;
  --font-kai: "Kaiti SC", "KaiTi", "STKaiti", 楷体, serif;
  --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", 黑体, sans-serif;

  /* 字号 */
  --t-hero: clamp(2.4rem, 6vw, 4.6rem);
  --t-h1: clamp(1.7rem, 3.2vw, 2.6rem);
  --t-h2: clamp(1.25rem, 2.1vw, 1.7rem);
  --t-h3: clamp(1.02rem, 1.5vw, 1.2rem);
  --t-body: clamp(0.94rem, 1.05vw, 1.04rem);
  --t-small: 0.84rem;
  --t-tiny: 0.72rem;

  /* 间距 */
  --s1: 0.25rem;
  --s2: 0.5rem;
  --s3: 0.75rem;
  --s4: 1rem;
  --s6: 1.5rem;
  --s8: 2rem;
  --s12: 3rem;
  --s16: 4rem;
  --s24: 6rem;

  /* 动效 */
  --ease-scroll: cubic-bezier(0.22, 0.61, 0.36, 1);
  --ease-in: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-out: cubic-bezier(0.5, 0, 0.75, 0);
}

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

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

body {
  margin: 0;
  min-height: 100%;
  background-color: var(--paper);
  color: var(--ink-700);
  font-family: var(--font-serif);
  font-size: var(--t-body);
  line-height: 1.85;
  letter-spacing: 0.012em;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* ── 宣纸底：多层渐变 + 噪声 ─────────────────────────────── */

body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: -2;
  background-color: var(--paper);
  background-image:
    radial-gradient(ellipse 70% 50% at 22% 18%, rgba(255, 253, 245, 0.85), transparent 62%),
    radial-gradient(ellipse 55% 45% at 78% 76%, rgba(250, 243, 228, 0.7), transparent 60%),
    radial-gradient(ellipse 90% 80% at 50% 50%, transparent 42%, rgba(196, 180, 152, 0.16) 100%);
}

body::after {
  content: '';
  position: fixed;
  inset: -20%;
  z-index: -1;
  opacity: 0.032;
  pointer-events: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='220' height='220'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.82' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='220' height='220' filter='url(%23n)'/%3E%3C/svg%3E");
  mix-blend-mode: multiply;
}

/* ── 排版 ─────────────────────────────────────────────── */

h1,
h2,
h3,
h4 {
  margin: 0;
  font-weight: 500;
  line-height: 1.32;
  color: var(--ink-900);
  letter-spacing: 0.02em;
}

p {
  margin: 0 0 var(--s4);
}

p:last-child {
  margin-bottom: 0;
}

a {
  color: var(--cinnabar);
  text-decoration: none;
  border-bottom: 1px solid rgba(157, 58, 48, 0.28);
  transition: border-color 0.2s, color 0.2s;
}

a:hover {
  border-bottom-color: var(--cinnabar);
}

strong {
  font-weight: 600;
  color: var(--ink-900);
}

em {
  font-style: normal;
  background: linear-gradient(transparent 62%, rgba(184, 145, 47, 0.24) 62%);
}

/* 竖排标题 */
.vertical {
  writing-mode: vertical-rl;
  text-orientation: upright;
  letter-spacing: 0.24em;
}

/* 楷体题跋 */
.kai {
  font-family: var(--font-kai);
}

/* 小字编号 */
.num {
  font-family: var(--font-sans);
  font-size: var(--t-tiny);
  letter-spacing: 0.18em;
  color: var(--ink-300);
  font-variant-numeric: tabular-nums;
}

/* ── 工具类 ─────────────────────────────────────────── */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.wrap {
  width: min(1180px, 100% - var(--s8));
  margin-inline: auto;
}

/* 焦点可见 */
:focus-visible {
  outline: 2px solid var(--cinnabar);
  outline-offset: 3px;
  border-radius: 2px;
}

/* ── 按钮：手绘风 ───────────────────────────────────── */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--s2);
  padding: 0.66rem 1.5rem;
  font-family: var(--font-kai);
  font-size: 1rem;
  letter-spacing: 0.16em;
  color: var(--ink-900);
  background: transparent;
  border: 1px solid var(--ink-500);
  border-radius: 1px;
  cursor: pointer;
  position: relative;
  transition: background 0.25s, color 0.25s, border-color 0.25s;
  text-indent: 0.16em;
}

.btn::after {
  content: '';
  position: absolute;
  inset: 2px;
  border: 1px solid transparent;
  border-radius: 1px;
  transition: border-color 0.25s;
  pointer-events: none;
}

.btn:hover {
  background: var(--ink-900);
  color: var(--paper);
  border-color: var(--ink-900);
}

.btn:hover::after {
  border-color: rgba(244, 239, 228, 0.28);
}

.btn--seal {
  color: var(--cinnabar);
  border-color: var(--cinnabar);
}

.btn--seal:hover {
  background: var(--cinnabar);
  color: var(--paper);
  border-color: var(--cinnabar);
}

.btn--ghost {
  border-color: var(--ink-150);
  color: var(--ink-500);
  font-size: 0.9rem;
  padding: 0.5rem 1rem;
  letter-spacing: 0.1em;
}

.btn--ghost:hover {
  background: var(--ink-500);
  border-color: var(--ink-500);
  color: var(--paper);
}

/* ── 引文块 ─────────────────────────────────────────── */

.quote-block {
  position: relative;
  margin: var(--s6) 0;
  padding: var(--s4) 0 var(--s4) var(--s6);
  border-left: 2px solid var(--gold);
  font-family: var(--font-kai);
  font-size: 1.04rem;
  line-height: 1.9;
  color: var(--ink-700);
}

.quote-block cite {
  display: block;
  margin-top: var(--s2);
  font-family: var(--font-sans);
  font-size: var(--t-small);
  font-style: normal;
  color: var(--ink-300);
  letter-spacing: 0.04em;
}

/* ── 来源标注 ───────────────────────────────────────── */

.src {
  font-family: var(--font-sans);
  font-size: var(--t-tiny);
  color: var(--ink-300);
  line-height: 1.6;
  letter-spacing: 0.02em;
}

.src::before {
  content: '出处 · ';
  opacity: 0.7;
}

/* ── 手绘分隔 ───────────────────────────────────────── */

.rule {
  height: 8px;
  margin: var(--s8) 0;
  opacity: 0.5;
}

/* ── 动效降级 ───────────────────────────────────────── */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

/* ── 选中 ───────────────────────────────────────────── */

::selection {
  background: rgba(184, 145, 47, 0.3);
  color: var(--ink-900);
}

/* ── 滚动条 ─────────────────────────────────────────── */

::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: rgba(90, 98, 91, 0.26);
  border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
  background: rgba(90, 98, 91, 0.42);
}