@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;700&display=swap');

/* ===== CSS 自定义属性 ===== */
:root {
  --c-black: #000000;
  --c-white: #ffffff;
  --c-accent: #000000;
  --c-gray-100: #f5f5f5;
  --c-gray-200: #e0e0e0;
  --c-gray-400: #9e9e9e;
  --c-gray-700: #424242;

  --base: 8px;
  --sp-1: 8px;
  --sp-2: 16px;
  --sp-3: 24px;
  --sp-4: 32px;
  --sp-5: 48px;
  --sp-6: 64px;
  --sp-7: 96px;
  --sp-8: 128px;

  --radius-card: 4px;

  --font-main: 'Space Grotesk', 'Helvetica Neue', Helvetica, Arial, sans-serif;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-bold: 700;

  --nav-height-brand: 64px;
  --nav-height-menu: 52px;
  --nav-total: 116px;

  --max-w: 1280px;
  --col-gap: 1rem;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-main);
  font-weight: var(--font-weight-normal);
  color: var(--c-black);
  background: var(--c-white);
  line-height: 1.6;
  overflow-x: hidden;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

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

ul {
  list-style: none;
}

/* ===== 布局骨架 ===== */
.site-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ===== ASIDE / 导航（两行：品牌行 + 菜单行）===== */
.site-aside {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--c-black);
  color: var(--c-white);
  width: 100%;
}

.brand-bar {
  display: flex;
  align-items: center;
  height: var(--nav-height-brand);
  padding: 0 var(--sp-4);
  border-bottom: 1px solid rgba(255,255,255,0.12);
}

.brand-link {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  min-height: 40px;
}

.brand__logo {
  height: 36px;
  width: auto;
  object-fit: contain;
}

.brand__wordmark {
  font-size: 1.25rem;
  font-weight: var(--font-weight-bold);
  letter-spacing: -0.02em;
  color: var(--c-white);
  text-transform: uppercase;
  line-height: 1;
}

.main-nav {
  width: 100%;
  background: var(--c-black);
}

.main-nav ul {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  height: var(--nav-height-menu);
  padding: 0 var(--sp-4);
  gap: 0;
  overflow-x: auto;
  scrollbar-width: none;
}

.main-nav ul::-webkit-scrollbar {
  display: none;
}

.main-nav li {
  flex-shrink: 0;
}

.main-nav li a {
  display: flex;
  align-items: center;
  height: var(--nav-height-menu);
  padding: 0 var(--sp-2);
  font-size: 0.875rem;
  font-weight: var(--font-weight-medium);
  color: rgba(255,255,255,0.75);
  letter-spacing: 0.02em;
  white-space: nowrap;
  transition: color 0.18s ease;
  border-bottom: 2px solid transparent;
}

.main-nav li a:hover,
.main-nav li a:focus-visible {
  color: var(--c-white);
  border-bottom-color: var(--c-white);
  outline: none;
}

/* div scroll-margin for sticky nav */
div[id] {
  scroll-margin-top: calc(var(--nav-total) + 16px);
}

/* ===== HERO ===== */
.hero {
  position: relative;
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--col-gap);
  min-height: 70vh;
  background: var(--c-black);
  overflow: hidden;
  align-items: center;
}

.hero__slash {
  position: absolute;
  right: 38%;
  top: 0;
  width: 120px;
  height: 100%;
  background: var(--c-white);
  transform: skewX(-8deg);
  z-index: 1;
  pointer-events: none;
}

.hero__content {
  grid-column: 1 / 7;
  position: relative;
  z-index: 2;
  padding: var(--sp-7) var(--sp-4) var(--sp-7) var(--sp-5);
  color: var(--c-white);
}

.hero__eyebrow {
  font-size: 0.75rem;
  font-weight: var(--font-weight-bold);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.55);
  margin-bottom: var(--sp-2);
}

.hero__title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: var(--font-weight-bold);
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: var(--sp-3);
  color: var(--c-white);
}

.hero__desc {
  font-size: 1.0625rem;
  line-height: 1.65;
  color: rgba(255,255,255,0.72);
  max-width: 42ch;
  margin-bottom: var(--sp-4);
}

.hero__cta {
  display: inline-flex;
  align-items: center;
  height: 48px;
  padding: 0 var(--sp-4);
  background: var(--c-white);
  color: var(--c-black);
  font-weight: var(--font-weight-bold);
  font-size: 0.9375rem;
  letter-spacing: 0.02em;
  border-radius: var(--radius-card);
  transition: background 0.18s ease, color 0.18s ease, transform 0.15s ease;
}

.hero__cta:hover,
.hero__cta:focus-visible {
  background: var(--c-gray-200);
  color: var(--c-black);
  transform: translateY(-2px);
  outline: none;
}

.hero__media {
  grid-column: 7 / 13;
  position: relative;
  z-index: 0;
  height: 100%;
  min-height: 70vh;
  overflow: hidden;
}

.hero__media .hero__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

.hero__media--empty {
  background: linear-gradient(135deg, #111 0%, #333 100%);
}

/* ===== 主内容区 ===== */
.site-main {
  flex: 1;
  background: var(--c-white);
}

.main-article {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: var(--sp-7) var(--sp-4);
}

.content-section {
  width: 100%;
}

/* 正文内部排版 */
.content-section h2,
.content-section h3 {
  font-weight: var(--font-weight-bold);
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-top: var(--sp-6);
  margin-bottom: var(--sp-3);
}

.content-section h2 {
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  padding-bottom: var(--sp-2);
  border-bottom: 2px solid var(--c-black);
}

.content-section h2 > span {
  display: inline;
}

.content-section h3 {
  font-size: clamp(1.125rem, 2vw, 1.5rem);
}

.content-section h3 > span {
  display: inline;
}

.content-section p {
  font-size: 1rem;
  line-height: 1.75;
  color: var(--c-gray-700);
  margin-bottom: var(--sp-3);
  max-width: 72ch;
}

.content-section ul,
.content-section ol {
  margin-left: var(--sp-3);
  margin-bottom: var(--sp-3);
}

.content-section li {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--c-gray-700);
  margin-bottom: var(--sp-1);
  list-style: disc;
}

.content-section ol li {
  list-style: decimal;
}

.content-section a {
  color: var(--c-black);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: opacity 0.15s;
}

.content-section a:hover {
  opacity: 0.65;
}

.content-section strong {
  font-weight: var(--font-weight-bold);
  color: var(--c-black);
}

.content-section blockquote {
  border-left: 4px solid var(--c-black);
  padding-left: var(--sp-3);
  margin: var(--sp-4) 0;
  font-style: normal;
  color: var(--c-gray-700);
}

.content-section table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: var(--sp-4);
  font-size: 0.9375rem;
}

.content-section th,
.content-section td {
  text-align: left;
  padding: var(--sp-2) var(--sp-2);
  border-bottom: 1px solid var(--c-gray-200);
}

.content-section th {
  font-weight: var(--font-weight-bold);
  background: var(--c-gray-100);
}

/* div 区块分隔 */
.content-section > div,
.content-section div {
  padding-top: var(--sp-5);
  padding-bottom: var(--sp-5);
  border-bottom: 1px solid var(--c-gray-200);
}

.content-section > div:last-child,
.content-section div:last-child {
  border-bottom: none;
}

/* ===== 页脚 ===== */
.site-footer {
  background: var(--c-black);
  color: var(--c-white);
  margin-top: var(--sp-7);
}

.footer__inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: var(--sp-6) var(--sp-4) var(--sp-4);
}

.footer__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-5);
  margin-bottom: var(--sp-5);
  padding-bottom: var(--sp-5);
  border-bottom: 1px solid rgba(255,255,255,0.12);
}

.footer__address {
  display: flex;
  flex-direction: column;
  gap: var(--sp-2);
  font-style: normal;
}

.footer__brand-name {
  font-size: 1.125rem;
  font-weight: var(--font-weight-bold);
  letter-spacing: -0.01em;
}

.footer__brand-desc {
  font-size: 0.875rem;
  line-height: 1.6;
  color: rgba(255,255,255,0.6);
  max-width: 38ch;
}

.footer__links-label {
  font-size: 0.75rem;
  font-weight: var(--font-weight-bold);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.45);
  margin-bottom: var(--sp-2);
}

.footer__links-col ul {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.footer__links-col li a {
  display: flex;
  align-items: center;
  min-height: 40px;
  padding: 2px 0;
  font-size: 0.9rem;
  color: rgba(255,255,255,0.7);
  transition: color 0.15s ease;
}

.footer__links-col li a:hover {
  color: var(--c-white);
}

.footer__bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--sp-2);
  font-size: 0.8125rem;
  color: rgba(255,255,255,0.45);
}

.footer__notice {
  text-align: right;
}

/* ===== 卡片样式（正文内部卡片）===== */
.card {
  background: var(--c-gray-100);
  border-radius: var(--radius-card);
  padding: var(--sp-3);
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.10);
}

/* ===== Scroll Reveal 动效 ===== */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .hero__cta,
  .card,
  .main-nav li a,
  .footer__links-col li a {
    transition: none;
  }
  html {
    scroll-behavior: auto;
  }
}

/* ===== 响应式断点 ===== */
@media (max-width: 1024px) {
  .hero__content {
    grid-column: 1 / 8;
    padding: var(--sp-6) var(--sp-3) var(--sp-6) var(--sp-4);
  }
  .hero__media {
    grid-column: 8 / 13;
  }
}

@media (max-width: 768px) {
  :root {
    --nav-height-brand: 56px;
    --nav-height-menu: 48px;
    --nav-total: 104px;
  }

  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .hero__slash {
    display: none;
  }

  .hero__content {
    grid-column: 1 / -1;
    padding: var(--sp-6) var(--sp-3);
    min-height: auto;
  }

  .hero__media {
    grid-column: 1 / -1;
    min-height: 280px;
    height: 280px;
  }

  .footer__grid {
    grid-template-columns: 1fr;
    gap: var(--sp-4);
  }

  .footer__notice {
    text-align: left;
  }

  .main-article {
    padding: var(--sp-5) var(--sp-3);
  }
}

@media (max-width: 480px) {
  .brand-bar {
    padding: 0 var(--sp-3);
  }

  .main-nav ul {
    padding: 0 var(--sp-2);
    gap: 0;
  }

  .main-nav li a {
    padding: 0 var(--sp-1);
    font-size: 0.8125rem;
  }

  .hero__content {
    padding: var(--sp-5) var(--sp-2);
  }

  .hero__cta {
    height: 44px;
    padding: 0 var(--sp-3);
  }

  .footer__inner {
    padding: var(--sp-5) var(--sp-3) var(--sp-3);
  }
}