/* ============================================================
   游咔网址指南 · 共享外壳样式 /assets/site.css
   草原路标体系：浮岛导航 + 里程刻度 + 夜间路标页脚
   ============================================================ */

:root {
  /* 自然矿物色 */
  --yk-green: #1F6F4A;
  --yk-green-deep: #0E3B2E;
  --yk-sky: #2C6E9B;
  --yk-sky-soft: #CBE7F4;
  --yk-sand: #EAD9B8;
  --yk-cream: #FAF6EC;
  --yk-orange: #E86A33;
  --yk-orange-deep: #B5471F;
  --yk-rock: #4B5563;
  --yk-moss: #8DAA7B;
  --yk-ink: #15261F;
  --yk-clay: #A65B45;

  /* 字体 */
  --yk-font-display: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --yk-font-body: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --yk-font-mono: "JetBrains Mono", "Roboto Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  /* 形状与节奏 */
  --yk-radius-pill: 999px;
  --yk-radius-sm: 12px;
  --yk-radius-md: 20px;
  --yk-radius-lg: 32px;
  --yk-shadow-soft: 0 18px 40px -26px rgba(21, 38, 31, 0.45);
  --yk-shadow-lift: 0 28px 60px -32px rgba(21, 38, 31, 0.55);
  --yk-max: 1200px;
  --yk-gutter: clamp(16px, 4vw, 40px);
  --yk-ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

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

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

body,
h1, h2, h3, h4, h5,
p, ul, ol, li, figure, figcaption, blockquote, dl, dd { margin: 0; }

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

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

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

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

:focus-visible {
  outline: 3px solid var(--yk-orange);
  outline-offset: 3px;
  border-radius: 8px;
}

/* ---------------- 基础排版 ---------------- */
body {
  min-height: 100vh;
  font-family: var(--yk-font-body);
  font-size: 1rem;
  font-weight: 400;
  line-height: 1.75;
  color: var(--yk-ink);
  letter-spacing: 0.01em;
  background-color: var(--yk-cream);
  background-image:
    radial-gradient(circle at 10% -10%, rgba(203, 231, 244, 0.85) 0%, rgba(203, 231, 244, 0) 44%),
    radial-gradient(circle at 92% 2%, rgba(234, 217, 184, 0.7) 0%, rgba(234, 217, 184, 0) 46%);
  background-repeat: no-repeat;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: var(--yk-font-display);
  font-weight: 800;
  line-height: 1.18;
  letter-spacing: -0.01em;
  color: var(--yk-ink);
  text-wrap: balance;
}

p { text-wrap: pretty; overflow-wrap: break-word; }

/* ---------------- 跳转链接 ---------------- */
.yk-skip {
  position: fixed;
  top: 10px;
  left: 12px;
  z-index: 300;
  padding: 10px 20px;
  border-radius: var(--yk-radius-pill);
  background: var(--yk-green-deep);
  color: #FFFFFF;
  font-weight: 600;
  font-size: 0.9rem;
  box-shadow: var(--yk-shadow-lift);
  transform: translateY(-220%);
  transition: transform 0.2s var(--yk-ease);
}

.yk-skip:focus {
  transform: translateY(0);
  outline-color: var(--yk-orange);
}

/* ============================================================
   头部：悬浮胶囊浮岛
   ============================================================ */
.yk-header {
  position: sticky;
  top: 0;
  z-index: 90;
  padding: clamp(10px, 1.5vw, 18px) var(--yk-gutter) 0;
  background: linear-gradient(180deg,
    rgba(250, 246, 236, 0.97) 0%,
    rgba(250, 246, 236, 0.88) 58%,
    rgba(250, 246, 236, 0) 100%);
  transition: padding 0.24s var(--yk-ease);
}

.yk-header[data-scrolled] { padding-top: 6px; }

.yk-header__island {
  max-width: var(--yk-max);
  margin-inline: auto;
  padding: 10px clamp(12px, 1.6vw, 18px);
  border: 1px solid rgba(31, 111, 74, 0.16);
  border-radius: var(--yk-radius-pill);
  background: rgba(255, 255, 255, 0.9);
  box-shadow: var(--yk-shadow-soft);
  backdrop-filter: blur(10px);
  transition: box-shadow 0.24s var(--yk-ease), padding 0.24s var(--yk-ease);
}

.yk-header[data-scrolled] .yk-header__island {
  padding-block: 5px;
  box-shadow: var(--yk-shadow-lift);
}

.yk-header__bar {
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 26px);
}

/* 品牌牌匾 */
.yk-brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
}

.yk-brand__mark {
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border-radius: 16px 16px 16px 5px;
  background: linear-gradient(150deg, var(--yk-green) 0%, var(--yk-green-deep) 100%);
  color: #FFFFFF;
  font-family: var(--yk-font-mono);
  font-size: 0.98rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  box-shadow: inset 0 -3px 0 rgba(0, 0, 0, 0.18), 0 10px 20px -14px rgba(14, 59, 46, 0.9);
}

.yk-brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.16;
}

.yk-brand__name {
  font-family: var(--yk-font-display);
  font-size: 1.06rem;
  font-weight: 800;
  color: var(--yk-ink);
}

.yk-brand__tagline {
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  color: var(--yk-sky);
}

/* 主导航 */
.yk-nav {
  flex: 1 1 auto;
  display: flex;
  justify-content: center;
}

.yk-nav__list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.yk-nav__item { display: block; }

.yk-nav__link {
  display: inline-block;
  padding: 9px 15px;
  border-radius: var(--yk-radius-pill);
  font-size: 0.94rem;
  font-weight: 600;
  color: var(--yk-ink);
  transition: background 0.18s var(--yk-ease), color 0.18s var(--yk-ease);
}

.yk-nav__link:hover {
  background: var(--yk-sky-soft);
  color: var(--yk-green-deep);
}

.yk-nav__link[aria-current="page"] {
  background: var(--yk-green);
  color: #FFFFFF;
  box-shadow: 0 10px 20px -12px rgba(31, 111, 74, 0.95);
}

.yk-nav__link[aria-current="page"]:hover {
  background: var(--yk-green-deep);
  color: #FFFFFF;
}

.yk-nav__cta { display: none; }

/* 右侧工具区 */
.yk-header__tools {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
}

.yk-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 13px;
  border: 1px dashed rgba(14, 59, 46, 0.3);
  border-radius: var(--yk-radius-pill);
  background: var(--yk-sand);
  color: var(--yk-green-deep);
  font-family: var(--yk-font-mono);
  font-size: 0.76rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  transition: background 0.18s var(--yk-ease), color 0.18s var(--yk-ease), border-color 0.18s var(--yk-ease);
}

.yk-chip:hover {
  background: var(--yk-orange);
  border-color: transparent;
  color: #FFFFFF;
}

.yk-chip__dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--yk-orange);
  box-shadow: 0 0 0 3px rgba(232, 106, 51, 0.22);
}

.yk-chip:hover .yk-chip__dot {
  background: #FFFFFF;
  box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.35);
}

/* 汉堡按钮 */
.yk-nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  border: 1px solid rgba(31, 111, 74, 0.28);
  border-radius: var(--yk-radius-pill);
  background: rgba(255, 255, 255, 0.78);
  color: var(--yk-green-deep);
  font-size: 0.88rem;
  font-weight: 600;
  transition: background 0.18s var(--yk-ease), border-color 0.18s var(--yk-ease);
}

.yk-nav-toggle:hover { background: var(--yk-sky-soft); }

.yk-nav-toggle__bars {
  position: relative;
  display: block;
  width: 18px;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: background 0.18s var(--yk-ease);
}

.yk-nav-toggle__bars::before,
.yk-nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform 0.2s var(--yk-ease);
}

.yk-nav-toggle__bars::before { top: -6px; }
.yk-nav-toggle__bars::after { top: 6px; }

.yk-nav-toggle[aria-expanded="true"] .yk-nav-toggle__bars { background: transparent; }
.yk-nav-toggle[aria-expanded="true"] .yk-nav-toggle__bars::before { transform: translateY(6px) rotate(45deg); }
.yk-nav-toggle[aria-expanded="true"] .yk-nav-toggle__bars::after { transform: translateY(-6px) rotate(-45deg); }

.yk-nav-toggle__label { line-height: 1; }

/* 里程刻度进度 */
.yk-header__progress {
  position: relative;
  max-width: var(--yk-max);
  height: 4px;
  margin: 10px auto 0;
  border-radius: var(--yk-radius-pill);
  overflow: hidden;
  background:
    repeating-linear-gradient(90deg,
      rgba(21, 38, 31, 0.14) 0 1px,
      rgba(21, 38, 31, 0) 1px 9px),
    rgba(21, 38, 31, 0.05);
}

.yk-progress__fill {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: var(--yk-radius-pill);
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--yk-green) 0%, var(--yk-sky) 55%, var(--yk-orange) 100%);
  transition: transform 0.14s linear;
}

/* ============================================================
   页脚：夜间路标带
   ============================================================ */
.yk-footer {
  position: relative;
  margin-top: clamp(48px, 8vw, 96px);
  padding-top: clamp(40px, 6vw, 76px);
  border-radius: clamp(28px, 4vw, 48px) clamp(28px, 4vw, 48px) 0 0;
  overflow: hidden;
  color: rgba(250, 246, 236, 0.86);
  background:
    radial-gradient(120% 150% at 8% 0%, #16543C 0%, var(--yk-green-deep) 54%, #082A21 100%);
}

.yk-footer__road {
  position: absolute;
  top: clamp(18px, 3vw, 30px);
  left: var(--yk-gutter);
  right: var(--yk-gutter);
  height: 2px;
  background: repeating-linear-gradient(90deg,
    rgba(203, 231, 244, 0.34) 0 18px,
    rgba(203, 231, 244, 0) 18px 36px);
  pointer-events: none;
}

.yk-footer__road::before,
.yk-footer__road::after {
  content: "";
  position: absolute;
  top: 50%;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  transform: translateY(-50%);
}

.yk-footer__road::before {
  left: 0;
  background: var(--yk-orange);
  box-shadow: 0 0 0 4px rgba(232, 106, 51, 0.22);
}

.yk-footer__road::after {
  right: 0;
  background: var(--yk-sky-soft);
  box-shadow: 0 0 0 4px rgba(203, 231, 244, 0.16);
}

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

.yk-footer__grid {
  display: grid;
  grid-template-columns: 1.4fr 0.85fr 0.85fr 1.15fr;
  gap: clamp(24px, 4vw, 44px);
  padding-top: clamp(26px, 4vw, 48px);
}

.yk-footer__brand { display: flex; flex-direction: column; gap: 14px; }

.yk-footer__logo {
  display: inline-block;
  font-family: var(--yk-font-display);
  font-size: 1.3rem;
  font-weight: 900;
  letter-spacing: 0.01em;
  color: #FFFFFF;
}

.yk-footer__logo:hover { color: var(--yk-sky-soft); }

.yk-footer__brand-line {
  font-size: 0.95rem;
  font-weight: 600;
  line-height: 1.6;
  color: var(--yk-sand);
  max-width: 30ch;
}

.yk-footer__stamps {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.yk-footer__stamp {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 6px 12px;
  border: 1px solid rgba(203, 231, 244, 0.22);
  border-radius: var(--yk-radius-pill);
  background: rgba(203, 231, 244, 0.1);
  font-size: 0.76rem;
  color: rgba(250, 246, 236, 0.9);
}

.yk-footer__stamp .yk-mono {
  color: var(--yk-sky-soft);
  font-weight: 700;
}

.yk-footer__col { display: flex; flex-direction: column; }

.yk-footer__title {
  margin-bottom: 14px;
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--yk-sky-soft);
}

.yk-footer__list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.yk-footer__link {
  display: inline-block;
  font-size: 0.94rem;
  color: rgba(250, 246, 236, 0.82);
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--yk-ease), border-color 0.18s var(--yk-ease);
}

.yk-footer__link:hover {
  color: #FFFFFF;
  border-bottom-color: var(--yk-orange);
}

.yk-footer__contact {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.yk-footer__contact-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.yk-footer__contact-key {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  color: var(--yk-moss);
}

.yk-footer__contact-value {
  font-size: 0.88rem;
  line-height: 1.6;
  color: rgba(250, 246, 236, 0.92);
  overflow-wrap: anywhere;
}

.yk-footer__contact-value--mono {
  font-family: var(--yk-font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

.yk-footer__note {
  margin-top: 14px;
  font-size: 0.79rem;
  line-height: 1.7;
  color: rgba(250, 246, 236, 0.6);
}

.yk-footer__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
  width: 100%;
  max-width: var(--yk-max);
  margin: clamp(24px, 4vw, 44px) auto 0;
  padding: 18px var(--yk-gutter);
  border-top: 1px solid rgba(203, 231, 244, 0.16);
  font-size: 0.8rem;
  color: rgba(250, 246, 236, 0.66);
}

.yk-footer__copy { display: flex; align-items: center; gap: 6px; }

.yk-footer__icp {
  font-family: var(--yk-font-mono);
  letter-spacing: 0.02em;
}

/* ============================================================
   通用工具与基础组件
   ============================================================ */
.yk-container {
  width: 100%;
  max-width: var(--yk-max);
  margin-inline: auto;
  padding-inline: var(--yk-gutter);
}

.yk-section { padding-block: clamp(32px, 5.5vw, 76px); }

.yk-mono {
  font-family: var(--yk-font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

.yk-display {
  font-family: var(--yk-font-display);
  font-weight: 900;
  font-size: clamp(2.1rem, 5vw, 4rem);
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--yk-ink);
}

.yk-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--yk-font-mono);
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--yk-sky);
}

.yk-eyebrow::before {
  content: "";
  width: 26px;
  height: 3px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--yk-green), var(--yk-orange));
}

.yk-lede {
  max-width: 60ch;
  font-size: clamp(1rem, 1.3vw, 1.15rem);
  line-height: 1.85;
  color: var(--yk-rock);
}

.yk-prose {
  max-width: 68ch;
  font-size: 1.02rem;
  line-height: 1.9;
  color: #2B3A33;
}

.yk-prose > * + * { margin-top: 1.1em; }

.yk-prose h2,
.yk-prose h3 { margin-top: 1.8em; }

.yk-prose a {
  color: var(--yk-sky);
  border-bottom: 1px solid rgba(44, 110, 155, 0.4);
}

.yk-prose a:hover { border-bottom-color: var(--yk-sky); }

.yk-prose ul,
.yk-prose ol {
  padding-left: 1.3em;
  list-style: disc;
}

.yk-prose ol { list-style: decimal; }

.yk-rule {
  height: 0;
  margin-block: clamp(24px, 4vw, 44px);
  border: 0;
  border-top: 2px dashed rgba(21, 38, 31, 0.16);
}

/* 按钮 */
.yk-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 20px;
  border: 1px solid transparent;
  border-radius: var(--yk-radius-pill);
  font-size: 0.94rem;
  font-weight: 600;
  line-height: 1.2;
  cursor: pointer;
  transition: transform 0.18s var(--yk-ease), background 0.18s var(--yk-ease),
    color 0.18s var(--yk-ease), border-color 0.18s var(--yk-ease), box-shadow 0.18s var(--yk-ease);
}

.yk-btn--primary {
  background: var(--yk-green);
  color: #FFFFFF;
  box-shadow: 0 14px 26px -18px rgba(31, 111, 74, 0.95);
}

.yk-btn--primary:hover {
  background: var(--yk-green-deep);
  transform: translateY(-1px);
}

.yk-btn--ghost {
  background: transparent;
  color: var(--yk-green-deep);
  border-color: rgba(31, 111, 74, 0.32);
}

.yk-btn--ghost:hover { background: rgba(31, 111, 74, 0.08); }

.yk-btn--sky {
  background: var(--yk-sky);
  color: #FFFFFF;
}

.yk-btn--sky:hover { background: #235A80; }

.yk-btn--orange {
  background: var(--yk-orange);
  color: #2A1206;
}

.yk-btn--orange:hover { background: #F0793F; }

.yk-btn--quiet {
  background: var(--yk-cream);
  color: var(--yk-ink);
  border-color: rgba(21, 38, 31, 0.14);
}

.yk-btn--quiet:hover { background: var(--yk-sand); }

/* 标签 */
.yk-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 12px;
  border-radius: var(--yk-radius-pill);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  background: var(--yk-sand);
  color: var(--yk-green-deep);
}

.yk-tag--green { background: rgba(31, 111, 74, 0.13); color: #17573A; }
.yk-tag--sky { background: var(--yk-sky-soft); color: #1B4F70; }
.yk-tag--clay { background: rgba(166, 91, 69, 0.15); color: #8A4632; }
.yk-tag--orange { background: rgba(232, 106, 51, 0.16); color: var(--yk-orange-deep); }

/* 卡片与网格 */
.yk-card {
  padding: clamp(18px, 2.4vw, 30px);
  border: 1px solid rgba(21, 38, 31, 0.08);
  border-radius: var(--yk-radius-lg);
  background: #FFFFFF;
  box-shadow: var(--yk-shadow-soft);
}

.yk-card--sand { background: var(--yk-sand); border-color: rgba(166, 138, 92, 0.3); }
.yk-card--sky { background: var(--yk-sky-soft); border-color: rgba(44, 110, 155, 0.22); }
.yk-card--deep { background: var(--yk-green-deep); color: rgba(250, 246, 236, 0.9); border-color: transparent; }
.yk-card--deep h2,
.yk-card--deep h3 { color: #FFFFFF; }

.yk-grid {
  display: grid;
  gap: clamp(16px, 2.4vw, 28px);
}

.yk-grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.yk-grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.yk-grid--auto { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }

/* 面包屑 */
.yk-breadcrumb { padding-block: clamp(10px, 2vw, 20px); }

.yk-breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: 0.82rem;
  color: var(--yk-rock);
}

.yk-breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.yk-breadcrumb__item + .yk-breadcrumb__item::before {
  content: "/";
  font-family: var(--yk-font-mono);
  color: rgba(75, 85, 99, 0.5);
}

.yk-breadcrumb__link {
  color: var(--yk-sky);
  border-bottom: 1px solid transparent;
  transition: border-color 0.18s var(--yk-ease);
}

.yk-breadcrumb__link:hover { border-bottom-color: var(--yk-sky); }

.yk-breadcrumb__current {
  font-weight: 600;
  color: var(--yk-ink);
}

/* 图片容器基础规则（页面阶段放置真实占位图） */
.yk-figure {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 0;
}

.yk-figure__frame {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  border: 1px solid rgba(21, 38, 31, 0.08);
  border-radius: var(--yk-radius-lg);
  background:
    radial-gradient(circle at 22% 18%, rgba(255, 255, 255, 0.65) 0%, rgba(255, 255, 255, 0) 55%),
    linear-gradient(135deg, var(--yk-sand) 0%, var(--yk-sky-soft) 100%);
}

.yk-figure__frame > img,
.yk-figure__frame > picture,
.yk-figure__frame > picture > img,
.yk-figure__frame > svg {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.yk-figure__frame--wide { aspect-ratio: 21 / 9; }
.yk-figure__frame--tall { aspect-ratio: 3 / 4; }
.yk-figure__frame--square { aspect-ratio: 1 / 1; }

.yk-figure__caption {
  font-size: 0.82rem;
  line-height: 1.65;
  color: var(--yk-rock);
}

/* 滚动显现 */
.yk-reveal {
  transition: opacity 0.5s var(--yk-ease), transform 0.5s var(--yk-ease);
}

.yk-reveal.yk-hidden {
  opacity: 0;
  transform: translateY(18px);
}

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 1120px) {
  .yk-nav__link { padding: 8px 11px; font-size: 0.9rem; }
  .yk-brand__tagline { letter-spacing: 0.1em; }
}

@media (max-width: 980px) {
  .yk-nav-toggle { display: inline-flex; }
  .yk-chip { display: none; }

  .yk-nav {
    position: absolute;
    top: calc(100% + 12px);
    left: 0;
    right: 0;
    display: none;
    flex-direction: column;
    justify-content: flex-start;
    padding: 14px;
    border: 1px solid rgba(31, 111, 74, 0.18);
    border-radius: var(--yk-radius-lg);
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--yk-shadow-lift);
    backdrop-filter: blur(12px);
  }

  .yk-nav[data-open] {
    display: block;
    animation: yk-drop 0.22s var(--yk-ease) both;
  }

  .yk-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 6px;
  }

  .yk-nav__link {
    display: block;
    padding: 13px 16px;
    border-radius: var(--yk-radius-md);
    font-size: 1rem;
  }

  .yk-nav__cta {
    display: flex;
    width: 100%;
    margin-top: 12px;
  }

  .yk-footer__grid { grid-template-columns: 1fr 1fr; }
  .yk-footer__brand { grid-column: 1 / -1; }

  .yk-grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@keyframes yk-drop {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 720px) {
  .yk-brand__mark { width: 42px; height: 42px; border-radius: 14px 14px 14px 5px; font-size: 0.9rem; }
  .yk-brand__name { font-size: 1rem; }
  .yk-brand__tagline { font-size: 0.68rem; letter-spacing: 0.1em; }
  .yk-header__tools .yk-btn--primary { display: none; }
  .yk-header__progress { height: 3px; margin-top: 8px; }
  .yk-footer__meta { flex-direction: column; align-items: flex-start; gap: 8px; }
}

@media (max-width: 640px) {
  .yk-grid--2,
  .yk-grid--3 { grid-template-columns: minmax(0, 1fr); }

  .yk-figure__frame { aspect-ratio: 4 / 3; }

  .yk-footer__grid { grid-template-columns: minmax(0, 1fr); }
  .yk-footer__brand { grid-column: auto; }
}

@media (max-width: 420px) {
  .yk-brand__tagline { display: none; }
  .yk-brand { gap: 9px; }
  .yk-nav-toggle { padding: 10px 12px; }
  .yk-nav-toggle__label { font-size: 0.82rem; }
}

/* ============================================================
   可访问性与减少动效
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  .yk-reveal,
  .yk-reveal.yk-hidden {
    opacity: 1;
    transform: none;
  }
}

@media print {
  .yk-header,
  .yk-skip,
  .yk-nav-toggle { display: none !important; }

  .yk-footer {
    margin-top: 0;
    border-radius: 0;
    background: none;
    color: var(--yk-ink);
  }

  .yk-footer__link,
  .yk-footer__note,
  .yk-footer__contact-value { color: var(--yk-ink); }
}