:root {
  --paper: #f4f0e8;
  --paper-deep: #e9e3d8;
  --ink: #1c1d1b;
  --ink-soft: #474844;
  --ink-light: #88877f;
  --qing: #55766f;
  --chi: #a84a3f;
  --huang: #c5a35a;
  --bai: #e7e2d6;
  --hei: #252927;
  --cinnabar: #a83b32;
  --seal-red: #9d3027;
  --line: rgba(28, 29, 27, 0.16);
  --line-light: rgba(28, 29, 27, 0.08);
  --warm-white: #eee9dd;
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", serif;
  --sans: "Noto Sans SC", "Source Han Sans SC", "Microsoft YaHei", sans-serif;
}

body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.8;
  overflow-x: hidden;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 999;
  pointer-events: none;
  opacity: 0.032;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120' viewBox='0 0 120 120'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.82' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='120' height='120' filter='url(%23n)' opacity='.42'/%3E%3C/svg%3E");
  background-size: 120px 120px;
}

::selection {
  color: var(--warm-white);
  background: var(--cinnabar);
}

:focus-visible {
  outline: 1px solid var(--cinnabar);
  outline-offset: 5px;
}

::-webkit-scrollbar {
  width: 6px;
}

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

::-webkit-scrollbar-thumb {
  background: rgba(37, 41, 39, 0.56);
}

.section-inner {
  width: min(90vw, 1320px);
  margin-inline: auto;
}

.section-title {
  display: grid;
  gap: 6px;
  align-content: start;
}

.section-title__index {
  color: var(--ink-light);
  font-size: 13px;
  letter-spacing: 0.22em;
}

.section-title h2 {
  font-family: var(--serif);
  font-size: clamp(42px, 5vw, 72px);
  font-weight: 560;
  line-height: 1.12;
  letter-spacing: 0.04em;
}

.section-title p {
  color: var(--ink-light);
  font-size: 12px;
  letter-spacing: 0.22em;
  line-height: 1.4;
}

.section-lede {
  max-width: 620px;
  margin-top: 22px;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: clamp(18px, 2vw, 24px);
}

.scroll-progress {
  position: fixed;
  z-index: 90;
  top: 0;
  right: 10px;
  width: 1px;
  height: calc(var(--scroll-progress, 0) * 100vh);
  background: rgba(28, 29, 27, 0.45);
  transform-origin: top;
  pointer-events: none;
}

.line-button {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  min-height: 44px;
  color: var(--ink);
  font-size: 15px;
  letter-spacing: 0.12em;
}

.line-button span {
  transition: transform 320ms var(--ease-out);
}

.line-button:hover span,
.line-button:focus-visible span {
  transform: translateX(6px);
}