:root {
  --color-primary: #004d40;
  --color-secondary: #cfa144;
  --color-accent: #8b2252;
  --color-bg-dark: #00251a;
  --color-bg-light: #f5f5f0;
  --color-text: #1a1a1a;
  --color-text-light: #ffffff;
  --font-heading: Impact, 'Arial Black', sans-serif;
  --font-body: Georgia, 'Times New Roman', serif;
  --border-thick: 4px;
  --shadow-heavy: 8px 8px 0 rgba(0,0,0,0.15);
  --shadow-heavy-accent: 8px 8px 0 rgba(139,34,82,0.25);
  --transition-speed: 0.3s ease;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  color: var(--color-text);
  background-color: var(--color-bg-light);
  display: flex; flex-direction: column; min-height: 100vh;
  line-height: 1.6;
}
img { max-width: 100%; display: block; }
a { color: var(--color-secondary); text-decoration: none; transition: color var(--transition-speed); }
a:hover { color: var(--color-accent); }
a:focus-visible { outline: 3px solid var(--color-secondary); outline-offset: 4px; border-radius: 2px; }

/* 排版 */
h1, h2, h3, h4, h5, h6 { font-family: var(--font-heading); font-weight: bold; line-height: 1.1; letter-spacing: 0.02em; }
h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }

/* 跳转链接 */
.skip-link {
  position: absolute; top: -100%; left: 1rem; padding: 0.5rem 1rem; background: var(--color-secondary);
  color: var(--color-text); font-family: var(--font-heading); z-index: 10000; border: var(--border-thick) solid var(--color-text);
}
.skip-link:focus { top: 0.5rem; }

/* 布局框架 */
.site-frame { display: flex; flex: 1; }

/* 侧边栏 */
.sidebar {
  width: 280px; min-height: 100vh; background: var(--color-bg-dark); color: var(--color-text-light);
  border-right: var(--border-thick) solid var(--color-secondary); display: flex; flex-direction: column;
  position: fixed; top: 0; left: 0; z-index: 1000; transition: transform var(--transition-speed);
  box-shadow: 4px 0 20px rgba(0,0,0,0.3);
}
.sidebar-inner { display: flex; flex-direction: column; height: 100vh; padding: 1.5rem; }
.brand { display: flex; flex-direction: column; margin-bottom: 2rem; }
.brand-zh { font-family: var(--font-heading); font-size: 2rem; color: var(--color-secondary); letter-spacing: 0.1em; }
.brand-en { font-family: var(--font-body); font-size: 0.8rem; color: rgba(207,161,68,0.7); letter-spacing: 0.2em; text-transform: uppercase; }
.nav-toggle { display: none; background: none; border: none; color: var(--color-text-light); cursor: pointer; padding: 0.5rem; position: absolute; top: 1rem; right: 1rem; }
.hamburger-line { display: block; width: 28px; height: 3px; background: var(--color-text-light); margin: 5px 0; border-radius: 2px; transition: var(--transition-speed); }
.nav-list { list-style: none; margin: 0; padding: 0; }
.nav-link {
  display: flex; align-items: center; padding: 0.8rem 1rem; font-family: var(--font-heading); font-size: 1.1rem;
  color: var(--color-text-light); border-right: 3px solid transparent; transition: all var(--transition-speed);
  text-transform: uppercase; letter-spacing: 0.05em;
}
.nav-link:hover, .nav-link:focus { color: var(--color-secondary); border-right-color: var(--color-secondary); background: rgba(207,161,68,0.1); }
.nav-link[aria-current="page"] { color: var(--color-secondary); border-right-color: var(--color-secondary); background: linear-gradient(90deg, rgba(207,161,68,0.15), transparent); }
.nav-index { font-family: var(--font-body); font-weight: bold; font-size: 0.85rem; color: var(--color-accent); margin-right: 0.75rem; width: 1.8rem; opacity: 0.8; }
.sidebar-meta { margin-top: auto; padding-top: 2rem; border-top: 1px solid rgba(207,161,68,0.3); display: flex; flex-direction: column; gap: 0.75rem; }
.sidebar-phone { font-family: var(--font-heading); color: var(--color-secondary); font-size: 1rem; }
.sidebar-cta { text-align: center; }

/* 内容区 */
.content-area { margin-left: 280px; flex: 1; width: calc(100% - 280px); }
#main-content:focus { outline: none; }

/* 页脚 */
.footer {
  background: var(--color-bg-dark); color: var(--color-text-light); border-top: var(--border-thick) solid var(--color-secondary);
  padding: 3rem 2rem 1.5rem; margin-top: auto;
}
.footer-inner { max-width: 1200px; margin: 0 auto; display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 2rem; }
.footer-brand .brand-zh { font-size: 1.8rem; }
.footer-brand .brand-en { font-size: 0.7rem; }
.footer-tagline { margin-top: 0.5rem; font-family: var(--font-body); color: rgba(255,255,255,0.6); font-style: italic; }
.footer-heading { font-family: var(--font-heading); font-size: 1rem; color: var(--color-secondary); margin-bottom: 1rem; text-transform: uppercase; }
.footer-nav a, .footer-contact span { display: block; margin-bottom: 0.5rem; color: rgba(255,255,255,0.8); transition: var(--transition-speed); }
.footer-nav a:hover { color: var(--color-secondary); }
.footer-legal { grid-column: 1 / -1; border-top: 1px solid rgba(207,161,68,0.2); padding-top: 1rem; margin-top: 1rem; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 0.5rem; font-size: 0.85rem; color: rgba(255,255,255,0.5); }

/* 共享组件 */
.btn {
  display: inline-block; font-family: var(--font-heading); text-transform: uppercase; letter-spacing: 0.1em;
  padding: 0.8rem 1.8rem; border: var(--border-thick) solid transparent; cursor: pointer; transition: all var(--transition-speed);
  font-size: 0.9rem; text-align: center; line-height: 1.2;
}
.btn:focus-visible { outline: 3px solid var(--color-secondary); outline-offset: 2px; }
@media (prefers-reduced-motion: no-preference) { .btn:hover { transform: scale(1.05); } }
.btn-primary { background: var(--color-primary); color: var(--color-text-light); border-color: var(--color-secondary); }
.btn-primary:hover { background: var(--color-secondary); color: var(--color-text); }
.btn-accent { background: var(--color-accent); color: var(--color-text-light); border-color: var(--color-accent); }
.btn-accent:hover { background: transparent; color: var(--color-accent); }

.card {
  background: #ffffff; border: var(--border-thick) solid var(--color-primary); box-shadow: var(--shadow-heavy);
  padding: 1.5rem; transition: var(--transition-speed);
}
@media (prefers-reduced-motion: no-preference) { .card:hover { box-shadow: var(--shadow-heavy-accent); transform: translateY(-2px); } }

.page-container { max-width: 1200px; margin: 0 auto; padding: 2rem; }

/* 滚动进度条 */
.scroll-progress { width: 100%; height: 4px; background: transparent; position: sticky; top: 0; z-index: 999; }
.scroll-progress-bar { height: 100%; width: 0%; background: linear-gradient(90deg, var(--color-secondary), var(--color-accent)); transition: width 0.1s linear; }

/* 标签页 */
[data-tab-list] { display: flex; gap: 0; border-bottom: 3px solid var(--color-primary); margin-bottom: 1.5rem; }
[data-tab] { background: none; border: none; padding: 0.75rem 1.5rem; font-family: var(--font-heading); font-size: 1rem; cursor: pointer; color: var(--color-text); opacity: 0.6; transition: var(--transition-speed); border-bottom: 3px solid transparent; margin-bottom: -3px; }
[data-tab]:hover { opacity: 1; }
[data-tab][data-active="true"] { opacity: 1; border-bottom-color: var(--color-accent); color: var(--color-accent); }
[data-tab-panel] { display: none; }
[data-tab-panel][data-active="true"] { display: block; }

/* 滚动显现 */
[data-reveal] { opacity: 0; transform: translateY(30px); transition: opacity 0.6s ease, transform 0.6s ease; }
[data-reveal][data-revealed] { opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce) { [data-reveal] { opacity: 1; transform: none; } }

/* 移动端响应 */
@media (max-width: 768px) {
  .sidebar { width: 100%; min-height: auto; position: relative; border-right: none; box-shadow: none; }
  .sidebar-inner { height: auto; flex-direction: row; flex-wrap: wrap; align-items: center; padding: 0.8rem 1rem; }
  .brand { margin-bottom: 0; flex: 1; }
  .brand-zh { font-size: 1.4rem; }
  .brand-en { font-size: 0.6rem; }
  .nav-toggle { display: block; position: static; }
  .nav { flex-basis: 100%; max-height: 0; overflow: hidden; transition: max-height 0.4s ease, opacity 0.3s ease; opacity: 0; }
  .nav[data-open] { max-height: 500px; opacity: 1; }
  .nav-list { margin-top: 1rem; }
  .nav-link { border-right: none; border-left: 3px solid transparent; justify-content: flex-start; }
  .nav-link[aria-current="page"] { border-left-color: var(--color-secondary); border-right: none; }
  .sidebar-meta { display: none; }
  .content-area { margin-left: 0; width: 100%; }
  .footer-inner { grid-template-columns: 1fr; }
  .footer-legal { flex-direction: column; text-align: center; }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .sidebar { width: 220px; }
  .content-area { margin-left: 220px; width: calc(100% - 220px); }
  .sidebar-phone { font-size: 0.85rem; }
}