/* ==========================================================================
   喵君官网 · 基础层 (Reset / Typography / Layout / Header / Footer)
   ========================================================================== */

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

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

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--fs-base);
  line-height: var(--lh-body);
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

/* 纸张肌理 + 顶部暖光晕，取代纯色平铺 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(70rem 42rem at 82% -14%, rgba(179, 64, 14, 0.07), transparent 62%),
    radial-gradient(56rem 40rem at -8% 6%, rgba(22, 20, 15, 0.045), transparent 60%);
}

body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.035;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='3'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

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

/* ---------- 排版 ---------- */

h1,
h2,
h3,
h4 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 600;
  line-height: var(--lh-title);
  letter-spacing: var(--ls-display);
  color: var(--color-ink);
}

p {
  margin: 0;
}

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

img,
svg {
  display: block;
  max-width: 100%;
}

ul,
ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

button {
  font: inherit;
  color: inherit;
}

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

/* ---------- 排版工具类 ---------- */

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.container--narrow {
  max-width: var(--container-narrow);
}

.label {
  font-family: var(--font-label);
  font-size: var(--fs-xs);
  letter-spacing: var(--ls-label);
  text-transform: uppercase;
  color: var(--color-muted);
}

.label--accent {
  color: var(--color-accent);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-label);
  font-size: var(--fs-xs);
  letter-spacing: var(--ls-label);
  text-transform: uppercase;
  color: var(--color-muted);
}

.eyebrow::before {
  content: "";
  width: 34px;
  height: 1px;
  background: var(--color-accent);
}

.lead {
  font-size: var(--fs-md);
  line-height: 1.9;
  color: var(--color-ink-soft);
}

.muted {
  color: var(--color-muted);
}

/* 大标题的「破格」处理：中文宋体 + 拉丁衬线数字 */
.display {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(2.4rem, 6.2vw, var(--fs-5xl));
  line-height: var(--lh-tight);
  letter-spacing: -0.03em;
}

.display em {
  font-style: normal;
  color: var(--color-accent);
}

.display--sm {
  font-size: clamp(2rem, 4.4vw, var(--fs-3xl));
}

.num {
  font-family: var(--font-display-latin);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "ss01";
}

/* ---------- 区块节奏 ---------- */

.section {
  padding-block: clamp(64px, 9vw, var(--space-9));
}

.section--tight {
  padding-block: clamp(48px, 6vw, var(--space-7));
}

.section--dark {
  background: var(--color-bg-deep);
  color: var(--color-on-dark);
}

.section--dark h1,
.section--dark h2,
.section--dark h3,
.section--dark h4 {
  color: var(--color-on-dark);
}

.section--dark .lead,
.section--dark .muted {
  color: var(--color-on-dark-muted);
}

.section--dark .label {
  color: var(--color-on-dark-muted);
}

.rule {
  height: 1px;
  background: var(--color-line);
  border: 0;
  margin: 0;
}

.section--dark .rule {
  background: var(--color-on-dark-line);
}

/* ---------- 页头 ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(245, 242, 236, 0.82);
  backdrop-filter: blur(14px) saturate(1.2);
  -webkit-backdrop-filter: blur(14px) saturate(1.2);
  border-bottom: 1px solid var(--color-line-soft);
  transition: box-shadow var(--dur-base) var(--ease-out),
    background var(--dur-base) var(--ease-out);
}

.site-header.is-scrolled {
  background: rgba(245, 242, 236, 0.95);
  box-shadow: var(--shadow-1);
}

.header-inner {
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

/* 猫头几何标志：两耳 + 圆角方脸 + 眼 */
.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  flex-shrink: 0;
}

.brand-mark {
  width: 34px;
  height: 34px;
  flex-shrink: 0;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand-name {
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.brand-sub {
  font-family: var(--font-label);
  font-size: 0.625rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-muted);
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  margin-left: auto;
}

.nav-link {
  position: relative;
  font-size: var(--fs-sm);
  color: var(--color-ink-soft);
  padding-block: 6px;
  transition: color var(--dur-fast) ease-out;
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 1px;
  background: var(--color-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur-base) var(--ease-out);
}

.nav-link:hover {
  color: var(--color-ink);
}

.nav-link:hover::after {
  transform: scaleX(1);
}

.nav-link.is-active {
  color: var(--color-ink);
  font-weight: 500;
}

.nav-link.is-active::after {
  transform: scaleX(1);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

/* 汉堡按钮：仅移动端出现 */
.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  background: none;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  cursor: pointer;
  position: relative;
}

.nav-toggle span {
  position: absolute;
  left: 12px;
  width: 18px;
  height: 1.5px;
  background: var(--color-ink);
  transition: transform var(--dur-base) var(--ease-out),
    opacity var(--dur-fast) ease-out;
}

.nav-toggle span:nth-child(1) {
  top: 16px;
}
.nav-toggle span:nth-child(2) {
  top: 21px;
}
.nav-toggle span:nth-child(3) {
  top: 26px;
}

.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(5px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-5px) rotate(-45deg);
}

@media (max-width: 880px) {
  .nav-toggle {
    display: block;
  }

  .nav {
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    margin: 0;
    padding: var(--space-2) var(--gutter) var(--space-5);
    background: var(--color-bg-elevated);
    border-bottom: 1px solid var(--color-line);
    box-shadow: var(--shadow-2);
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--dur-base) var(--ease-out),
      transform var(--dur-base) var(--ease-out),
      visibility var(--dur-base);
  }

  .nav.is-open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-link {
    padding-block: 14px;
    border-bottom: 1px solid var(--color-line-soft);
  }

  .nav-link::after {
    display: none;
  }

  .header-actions .btn {
    display: none;
  }
}

/* ---------- 页脚 ---------- */

.site-footer {
  background: var(--color-bg-deep);
  color: var(--color-on-dark-muted);
  padding-block: var(--space-8) var(--space-6);
}

.footer-top {
  display: grid;
  grid-template-columns: 1.4fr repeat(3, 1fr);
  gap: var(--space-7) var(--space-6);
  padding-bottom: var(--space-7);
  border-bottom: 1px solid var(--color-on-dark-line);
}

.footer-brand .brand-name {
  color: var(--color-on-dark);
}

.footer-brand .brand-sub {
  color: var(--color-on-dark-muted);
}

.footer-brand p {
  margin-top: var(--space-4);
  font-size: var(--fs-sm);
  max-width: 30ch;
}

.footer-col h4 {
  font-family: var(--font-label);
  font-size: var(--fs-xs);
  letter-spacing: var(--ls-label);
  text-transform: uppercase;
  color: var(--color-on-dark);
  margin-bottom: var(--space-4);
  font-weight: 500;
}

.footer-col li + li {
  margin-top: 10px;
}

.footer-col a {
  font-size: var(--fs-sm);
  transition: color var(--dur-fast) ease-out;
}

.footer-col a:hover {
  color: var(--color-on-dark);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4) var(--space-6);
  justify-content: space-between;
  align-items: center;
  padding-top: var(--space-5);
  font-size: var(--fs-xs);
  font-family: var(--font-label);
  letter-spacing: 0.04em;
}

.footer-bottom .dot {
  opacity: 0.45;
}

@media (max-width: 880px) {
  .footer-top {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-6);
  }
}

@media (max-width: 560px) {
  .footer-top {
    grid-template-columns: 1fr;
  }
}

/* ---------- 回到顶部 ---------- */

.to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 46px;
  height: 46px;
  display: grid;
  place-items: center;
  background: var(--color-bg-deep);
  color: var(--color-on-dark);
  border: 0;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-2);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity var(--dur-base) var(--ease-out),
    transform var(--dur-base) var(--ease-out),
    visibility var(--dur-base),
    background var(--dur-fast) ease-out;
  z-index: 30;
}

.to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.to-top:hover {
  background: var(--color-accent);
}

.to-top svg {
  width: 16px;
  height: 16px;
}