/* ============================
   RESET & 基础变量
   ============================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --color-primary: #CC2936;
  --color-secondary: #1E90FF;
  --color-accent: #FFD700;
  --color-bg-light: #F8F8F8;
  --color-bg-dark: #1A1A2E;
  --color-text: #222222;
  --color-text-light: #FFFFFF;
  --color-data: #FF6347;
  --font-heading: Impact, sans-serif;
  --font-body: 'Google Sans', Arial, sans-serif;
  --font-number: 'Courier New', monospace;
  --font-size-base: 16px;
  --scale: 1.25;
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 2rem;
  --space-lg: 4rem;
  --max-width: 1200px;
  --header-height: 80px;
}
html { scroll-behavior: smooth; font-size: var(--font-size-base); }
body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg-light);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
:focus-visible { outline: 3px solid var(--color-accent); outline-offset: 2px; }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
  html { scroll-behavior: auto; }
}
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 var(--space-sm); }

/* ============================
   SKIP LINK
   ============================ */
.skip-link {
  position: absolute; top: -100vh; left: 0; z-index: 9999;
  background: var(--color-primary); color: #fff;
  padding: 0.5rem 1rem; text-decoration: none; font-weight: bold;
}
.skip-link:focus { top: 0; }

/* ============================
   HEADER
   ============================ */
.header {
  position: fixed; top: 0; left: 0; width: 100%; z-index: 1000;
  background: linear-gradient(135deg, var(--color-bg-dark) 0%, #0f0f1f 100%);
  color: var(--color-text-light);
  box-shadow: 0 2px 20px rgba(0,0,0,0.3);
}
.header__inner {
  display: flex; align-items: center; justify-content: space-between;
  height: var(--header-height); position: relative; z-index: 2;
}
.header__brand { display: flex; align-items: baseline; gap: 0.75rem; }
.header__logo {
  font-family: var(--font-heading); font-size: 1.8rem; color: var(--color-primary);
  text-decoration: none; letter-spacing: 0.05em;
}
.header__tagline { font-size: 0.8rem; color: var(--color-accent); display: none; }
@media (min-width: 768px) { .header__tagline { display: inline; } }

.header__toggle {
  display: flex; flex-direction: column; gap: 5px;
  background: none; border: none; cursor: pointer; padding: 0.5rem;
}
.header__toggle-line {
  display: block; width: 24px; height: 2px; background: var(--color-text-light);
  transition: transform 0.3s;
}
.header[data-open] .header__toggle-line:nth-child(1) { transform: rotate(45deg) translate(5px,5px); }
.header[data-open] .header__toggle-line:nth-child(2) { opacity: 0; }
.header[data-open] .header__toggle-line:nth-child(3) { transform: rotate(-45deg) translate(5px,-5px); }

.header__nav { display: none; }
.header[data-open] .header__nav {
  display: block;
  position: absolute; top: var(--header-height); left: 0; width: 100%;
  background: var(--color-bg-dark); padding: var(--space-sm);
}
.header__nav-list {
  list-style: none; display: flex; flex-direction: column; gap: var(--space-xs);
}
.header__nav-link {
  display: block; padding: 0.75rem 1rem; color: var(--color-text-light);
  text-decoration: none; font-size: 1rem; font-weight: 500;
  border-left: 3px solid transparent; transition: all 0.3s;
}
.header__nav-link:hover, .header__nav-link:focus {
  color: var(--color-accent); border-left-color: var(--color-primary);
}
.header__nav-link[aria-current="page"] {
  color: var(--color-primary); border-left-color: var(--color-primary);
  font-weight: bold;
}
@media (min-width: 768px) {
  .header__toggle { display: none; }
  .header__nav { display: block; position: static; background: transparent; padding: 0; }
  .header__nav-list { flex-direction: row; gap: 0.25rem; }
  .header__nav-link { border-left: none; border-bottom: 3px solid transparent; padding: 0.5rem 0.75rem; }
  .header__nav-link:hover { border-bottom-color: var(--color-accent); }
  .header__nav-link[aria-current="page"] { border-bottom-color: var(--color-primary); }
}

/* 波浪曲线装饰 */
.header__wave {
  position: absolute; bottom: -12px; left: 0; width: 100%; height: 24px;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1200 24'%3E%3Cpath d='M0,12 C150,0 350,24 600,12 C850,0 1050,24 1200,12 L1200,24 L0,24 Z' fill='%231A1A2E'/%3E%3C/svg%3E") repeat-x;
  background-size: 1200px 24px;
  pointer-events: none; z-index: 1;
}

/* ============================
   FOOTER
   ============================ */
.footer {
  background: var(--color-bg-dark); color: var(--color-text-light);
  padding: var(--space-lg) 0 var(--space-sm);
  margin-top: var(--space-lg);
}
.footer__inner {
  display: grid; grid-template-columns: 1fr; gap: var(--space-md);
}
@media (min-width: 768px) {
  .footer__inner { grid-template-columns: 1fr 1fr 1fr; }
}
.footer__heading {
  font-family: var(--font-heading); font-size: 1.1rem;
  color: var(--color-primary); margin-bottom: var(--space-sm);
  border-bottom: 2px solid var(--color-secondary); padding-bottom: 0.5rem;
}
.footer__text { font-size: 0.9rem; margin-bottom: 0.5rem; }
.footer__text a { color: var(--color-accent); text-decoration: underline; }
.footer__links { list-style: none; }
.footer__links li { margin-bottom: 0.5rem; }
.footer__links a {
  color: var(--color-text-light); text-decoration: none; transition: color 0.3s;
}
.footer__links a:hover { color: var(--color-accent); }
.footer__bottom {
  text-align: center; border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: var(--space-sm); margin-top: var(--space-md);
  font-size: 0.85rem; opacity: 0.8;
}
.footer__icp { margin-bottom: 0.25rem; }

/* ============================
   BASE COMPONENTS
   ============================ */
.btn {
  display: inline-block; padding: 0.6rem 1.5rem; border: 2px solid transparent;
  font-family: var(--font-body); font-size: 1rem; font-weight: 600;
  text-decoration: none; cursor: pointer; transition: all 0.3s; border-radius: 4px;
}
.btn--primary { background: var(--color-primary); color: #fff; border-color: var(--color-primary); }
.btn--primary:hover { background: transparent; color: var(--color-primary); }
.btn--outline { background: transparent; color: var(--color-secondary); border-color: var(--color-secondary); }
.btn--outline:hover { background: var(--color-secondary); color: #fff; }

.breadcrumb {
  font-size: 0.85rem; padding: var(--space-xs) 0; color: #666;
}
.breadcrumb a { color: var(--color-secondary); text-decoration: none; }
.breadcrumb a:hover { text-decoration: underline; }
.breadcrumb span { margin: 0 0.35rem; color: #888; }

/* 可展开面板 */
.panel { border: 1px solid #ddd; border-radius: 6px; overflow: hidden; margin-bottom: var(--space-sm); }
.panel__toggle {
  display: flex; justify-content: space-between; align-items: center;
  width: 100%; padding: var(--space-sm) var(--space-md);
  background: var(--color-bg-light); border: none; cursor: pointer;
  font-family: var(--font-body); font-size: 1rem; font-weight: 600;
  color: var(--color-text); transition: background 0.3s;
}
.panel__toggle:hover { background: #e8e8e8; }
.panel__toggle::after {
  content: '+'; font-size: 1.4rem; transition: transform 0.3s;
}
.panel--open .panel__toggle::after { transform: rotate(45deg); }
.panel__content {
  max-height: 0; overflow: hidden; transition: max-height 0.4s ease, padding 0.4s ease;
  padding: 0 var(--space-md);
}
.panel--open .panel__content {
  max-height: 500px; padding: var(--space-sm) var(--space-md);
}

/* 滚动显现基本样式（供页面使用） */
[data-scroll-fade] {
  opacity: 0; transform: translateY(20px); transition: opacity 0.6s, transform 0.6s;
}
[data-scroll-fade].visible {
  opacity: 1; transform: translateY(0);
}
@media (prefers-reduced-motion: reduce) {
  [data-scroll-fade] { transition: none; }
  [data-scroll-fade].visible { opacity: 1; transform: none; }
}

/* 通用布局 */
main { padding-top: var(--header-height); min-height: 60vh; }
.page-content { padding: var(--space-md) 0; }