/* 轻书 · 全局 */
:root {
  --ink: #1f1b18;
  --ink-soft: #4a423c;
  --paper: #f6f1e9;
  --paper-deep: #ebe4d8;
  --accent: #8b3a2f;
  --accent-hover: #6f2e25;
  --gold: #b8956c;
  --radius: 12px;
  --shadow: 0 18px 48px rgba(31, 27, 24, 0.08);
  --font-serif: "Noto Serif SC", "Songti SC", serif;
  --font-sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --max: 1080px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-weight: 400;
  color: var(--ink-soft);
  background: var(--paper);
  line-height: 1.7;
  min-height: 100vh;
}

.grain {
  pointer-events: none;
  position: fixed;
  inset: 0;
  z-index: 0;
  opacity: 0.045;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

a {
  color: inherit;
  text-decoration: none;
}

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

.site-header,
main,
.site-footer {
  position: relative;
  z-index: 1;
}

/* 顶栏 */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  max-width: var(--max);
  margin: 0 auto;
  padding: 1.25rem 0 1.5rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-serif);
  color: var(--ink);
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 8px;
  background: var(--ink);
  color: var(--paper);
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.brand-name {
  font-size: 1.25rem;
  font-weight: 600;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  border: none;
  background: transparent;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  height: 2px;
  width: 1.35rem;
  margin: 0 auto;
  background: var(--ink);
  border-radius: 1px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1.75rem;
  font-size: 0.95rem;
}

.site-nav a {
  color: var(--ink-soft);
}

.nav-cta {
  padding: 0.45rem 1rem;
  border-radius: 999px;
  background: var(--ink);
  color: var(--paper) !important;
  font-weight: 500;
}

.nav-cta:hover {
  background: var(--accent);
  color: var(--paper) !important;
}

@media (max-width: 720px) {
  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: fixed;
    top: 0;
    right: 0;
    height: 100%;
    width: min(280px, 82vw);
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    padding: 5rem 1.5rem 2rem;
    background: var(--paper-deep);
    box-shadow: var(--shadow);
    transform: translateX(100%);
    transition: transform 0.28s ease;
  }

  .site-nav.is-open {
    transform: translateX(0);
  }

  .site-nav a {
    width: 100%;
    padding: 0.85rem 0;
    border-bottom: 1px solid rgba(31, 27, 24, 0.08);
  }

  .site-nav .nav-cta {
    margin-top: 1rem;
    text-align: center;
    width: 100%;
  }
}

body.nav-open {
  overflow: hidden;
}

/* Hero */
.hero {
  padding: 2rem 1.5rem 4rem;
}

.hero-inner {
  max-width: var(--max);
  margin: 0 auto;
}

.hero-eyebrow {
  font-size: 1rem;
  letter-spacing: 0.35em;
  text-transform: uppercase;
  color: var(--gold);
  margin: 0 0 1.25rem;
  font-weight: 500;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(2.25rem, 6vw, 3.5rem);
  font-weight: 600;
  color: var(--ink);
  line-height: 1.25;
  margin: 0 0 1.25rem;
  letter-spacing: 0.02em;
}

.hero-title-accent {
  color: var(--accent);
}

.hero-lead {
  max-width: 34rem;
  margin: 0 0 2rem;
  font-size: 1.05rem;
  font-weight: 300;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 3rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.35rem;
  border-radius: 999px;
  font-size: 0.95rem;
  font-weight: 500;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  color: #fff;
}

.btn-ghost {
  background: transparent;
  color: var(--ink);
  border-color: rgba(31, 27, 24, 0.2);
}

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

.hero-paper {
  position: relative;
  max-width: 420px;
  margin: 0;
  padding: 2rem 2rem 2.25rem;
  background: #fffef9;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid rgba(139, 58, 47, 0.12);
}

.paper-lines {
  position: absolute;
  inset: 2.5rem 1.75rem 2rem;
  background: repeating-linear-gradient(
    to bottom,
    transparent,
    transparent 1.65rem,
    rgba(74, 66, 60, 0.06) 1.65rem,
    rgba(74, 66, 60, 0.06) calc(1.65rem + 1px)
  );
  pointer-events: none;
}

.paper-quote {
  position: relative;
  font-family: var(--font-serif);
  font-size: 1.35rem;
  color: var(--ink);
  margin: 0;
  padding-top: 0.25rem;
}

/* 区块通用 */
.section {
  padding: 4rem 1.5rem;
}

.section:nth-of-type(even) {
  background: linear-gradient(180deg, var(--paper-deep) 0%, var(--paper) 100%);
}

.section-inner {
  max-width: var(--max);
  margin: 0 auto;
}

.section-title {
  font-family: var(--font-serif);
  font-size: clamp(1.6rem, 3.5vw, 2rem);
  color: var(--ink);
  margin: 0 0 1rem;
  font-weight: 600;
}

.section-sub {
  max-width: 40rem;
  margin: 0 0 2.5rem;
  font-weight: 300;
  font-size: 1.02rem;
}

/* 理念网格 */
.essence-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.essence-grid li {
  padding: 1.5rem;
  background: #fffef9;
  border-radius: var(--radius);
  border: 1px solid rgba(31, 27, 24, 0.06);
  box-shadow: 0 8px 24px rgba(31, 27, 24, 0.04);
}

.essence-icon {
  display: inline-block;
  font-family: var(--font-serif);
  font-size: 1.5rem;
  color: var(--accent);
  margin-bottom: 0.75rem;
}

.essence-grid h3 {
  font-size: 1.1rem;
  color: var(--ink);
  margin: 0 0 0.5rem;
  font-weight: 600;
}

.essence-grid p {
  margin: 0;
  font-size: 0.92rem;
  font-weight: 300;
}

@media (max-width: 900px) {
  .essence-grid {
    grid-template-columns: 1fr;
  }
}

/* 特点 */
.features-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.feature-card {
  padding: 1.5rem 1.5rem 1.65rem;
  border-radius: var(--radius);
  background: rgba(255, 254, 249, 0.7);
  border: 1px dashed rgba(139, 58, 47, 0.25);
}

.feature-card h3 {
  margin: 0 0 0.5rem;
  font-size: 1.05rem;
  color: var(--ink);
  font-weight: 600;
}

.feature-card p {
  margin: 0;
  font-size: 0.92rem;
  font-weight: 300;
}

@media (max-width: 640px) {
  .features-list {
    grid-template-columns: 1fr;
  }
}

/* 场景 */
.scenes-wrap {
  display: grid;
  gap: 1.5rem;
}

.scene-quote {
  margin: 0;
  padding: 0;
  border: none;
  font-family: var(--font-serif);
  font-size: clamp(1.15rem, 2.5vw, 1.35rem);
  color: var(--ink);
  line-height: 1.75;
}

.scene-quote p {
  margin: 0;
}

.scene-tags {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.scene-tags li {
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  font-size: 0.85rem;
  background: rgba(139, 58, 47, 0.08);
  color: var(--ink-soft);
}

/* CTA */
.cta {
  padding-bottom: 5rem;
}

.cta-inner {
  text-align: center;
}

.cta-inner .section-title {
  margin-bottom: 0.75rem;
}

.cta-text {
  max-width: 28rem;
  margin: 0 auto 1.75rem;
  font-weight: 300;
}

.cta-form {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  justify-content: center;
  align-items: center;
  max-width: 480px;
  margin: 0 auto 0.75rem;
}

.cta-form input[type="email"] {
  flex: 1 1 200px;
  min-width: 0;
  padding: 0.65rem 1rem;
  border-radius: 999px;
  border: 1px solid rgba(31, 27, 24, 0.15);
  background: #fffef9;
  font-family: var(--font-sans);
  font-size: 0.95rem;
}

.cta-form input:focus {
  outline: 2px solid rgba(139, 58, 47, 0.35);
  outline-offset: 2px;
}

.cta-note {
  margin: 0;
  font-size: 0.8rem;
  color: rgba(74, 66, 60, 0.75);
}

.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;
}

/* 页脚 */
.site-footer {
  border-top: 1px solid rgba(31, 27, 24, 0.08);
  padding: 2rem 1.5rem;
}

.footer-inner {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.footer-brand {
  font-family: var(--font-serif);
  font-weight: 600;
  color: var(--ink);
  margin: 0;
}

.footer-meta {
  text-align: right;
}

.footer-copy {
  margin: 0;
  font-size: 0.85rem;
  color: rgba(74, 66, 60, 0.8);
}

.footer-icp {
  margin: 0.35rem 0 0;
  font-size: 0.85rem;
}

.footer-icp a {
  color: rgba(74, 66, 60, 0.85);
}

.footer-icp a:hover {
  color: var(--accent);
}

@media (max-width: 520px) {
  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }

  .footer-meta {
    text-align: left;
  }
}