:root {
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-primary-light: #eff6ff;
  --color-accent: #0ea5e9;
  --color-success: #10b981;
  --color-text-dark: #0f172a;
  --color-text-mid: #475569;
  --color-text-light: #94a3b8;
  --color-border: #e2e8f0;
  --color-surface: #ffffff;
  --color-surface-muted: #f8fafc;
  --color-surface-blue: #f0f7ff;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --radius-sm: 12px;
  --radius-md: 20px;
  --radius-lg: 32px;
  --max-width: 1400px;
  --header-height: 80px;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  margin: 0;
  font-family: "Inter", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  background: var(--color-surface);
  color: var(--color-text-dark);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  background-image: 
    radial-gradient(circle at 2px 2px, #e2e8f0 1px, transparent 0);
  background-size: 40px 40px;
}

.site-skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 100;
  padding: 12px 24px;
  background: var(--color-primary);
  color: #ffffff;
  font-size: 14px;
  font-weight: 700;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
}

.site-skip-link:focus {
  left: 50%;
  transform: translateX(-50%);
  top: 0;
  outline: none;
}

.site-shell {
  max-width: var(--max-width);
  margin: 0 auto;
  padding-inline: 32px;
}

.site-section {
  padding-block: 120px;
}

.site-section-muted {
  background: var(--color-surface-muted);
  padding-block: 120px;
  border-block: 1px solid var(--color-border);
}

.site-section-accent {
  background: var(--color-surface-blue);
  border-block: 1px solid var(--color-primary-light);
  padding-block: 120px;
}

/* --- Header --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(20px);
  background: rgba(255, 255, 255, 0.8);
  border-bottom: 1px solid var(--color-border);
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.site-header.is-scrolled {
  background: rgba(255, 255, 255, 0.95);
  box-shadow: var(--shadow-sm);
  padding-block: 4px;
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  min-height: var(--header-height);
}

.site-brand {
  display: flex;
  align-items: center;
  gap: 16px;
  min-width: 0;
}

.site-brand__mark {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  color: #fff;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  box-shadow: 0 8px 20px -4px rgba(37, 99, 235, 0.3);
  flex-shrink: 0;
}

.site-brand__title {
  font-size: 20px;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--color-text-dark);
}

.site-brand__subtitle {
  margin-top: 2px;
  font-size: 11px;
  color: var(--color-text-light);
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.site-nav-link {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text-mid);
  padding: 12px 0;
  position: relative;
  transition: all 0.3s ease;
}

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

.site-nav-link.is-active {
  color: var(--color-primary);
}

.site-nav-link.is-active::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: var(--color-primary);
  border-radius: 99px;
}

.site-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  height: 48px;
  padding-inline: 28px;
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 700;
  border: 1px solid transparent;
  white-space: nowrap;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.site-btn:active {
  transform: scale(0.96);
}

.site-btn--primary {
  color: #fff;
  background: var(--color-primary);
  box-shadow: 0 10px 20px -5px rgba(37, 99, 235, 0.4);
}

.site-btn--primary:hover {
  background: var(--color-primary-dark);
  box-shadow: 0 25px 30px -10px rgba(37, 99, 235, 0.3);
  transform: translateY(-2px);
}

.site-btn--ghost {
  color: var(--color-text-dark);
  background: transparent;
  border-color: var(--color-border);
}

.site-btn--ghost:hover {
  background: var(--color-surface-muted);
  border-color: #cbd5e1;
}

.site-btn--light {
  color: var(--color-primary);
  background: #fff;
  box-shadow: var(--shadow-sm);
}

.site-btn--light:hover {
  background: var(--color-primary-light);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.site-menu-toggle {
  display: inline-flex;
  width: 48px;
  height: 48px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  background: #fff;
  color: var(--color-text-mid);
}

.site-mobile-nav {
  display: none;
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.site-mobile-nav.is-open {
  display: block;
  max-height: 600px;
  padding-bottom: 32px;
  border-top: 1px solid var(--color-border);
}

.site-mobile-nav a {
  display: block;
  padding: 16px 0;
  font-size: 17px;
  font-weight: 700;
  color: var(--color-text-dark);
}

/* --- Hero --- */
.site-hero-band {
  background: radial-gradient(at 0% 0%, rgba(37, 99, 235, 0.1) 0px, transparent 50%),
              radial-gradient(at 100% 0%, rgba(14, 165, 233, 0.1) 0px, transparent 50%),
              var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.site-shell--hero {
  padding-top: 140px;
  padding-bottom: 140px;
}

.site-label {
  display: inline-flex;
  align-items: center;
  padding: 10px 20px;
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-primary);
  background: var(--color-primary-light);
  border-radius: 999px;
}

.site-heading {
  font-size: clamp(2.5rem, 7vw, 3.5rem);
  font-weight: 900;
  letter-spacing: -0.04em;
  line-height: 1.15;
  color: var(--color-text-dark);
}

.site-hero-heading {
  font-size: clamp(3.5rem, 12vw, 5.5rem);
  font-weight: 900;
  letter-spacing: -0.06em;
  line-height: 1;
  color: var(--color-text-dark);
}

.site-body {
  font-size: 18px;
  color: var(--color-text-mid);
}

.site-body--lg {
  font-size: 20px;
  line-height: 1.8;
}

/* --- Cards --- */
.site-card {
  background: #ffffff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 48px;
  box-shadow: var(--shadow-sm);
  transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}

.site-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 6px;
  background: linear-gradient(to right, var(--color-primary), var(--color-accent));
  opacity: 0;
  transition: opacity 0.4s ease;
}

.site-card--interactive:hover {
  transform: translateY(-12px);
  border-color: var(--color-primary-light);
  box-shadow: var(--shadow-lg);
}

.site-card--interactive:hover::before {
  opacity: 1;
}

.site-card--elevated {
  box-shadow: var(--shadow-md);
}

/* --- Buttons --- */
.site-primary-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 18px 36px;
  border-radius: var(--radius-sm);
  background: var(--color-primary);
  color: #ffffff;
  font-size: 18px;
  font-weight: 800;
  border: none;
  cursor: pointer;
  box-shadow: 0 15px 30px -5px rgba(37, 99, 235, 0.4);
  transition: all 0.4s ease;
}

.site-primary-btn:hover {
  background: var(--color-primary-dark);
  transform: translateY(-3px);
  box-shadow: 0 25px 40px -10px rgba(37, 99, 235, 0.4);
}

.site-ghost-link {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--color-primary);
  font-size: 18px;
  font-weight: 800;
  transition: all 0.3s ease;
}

.site-ghost-link:hover {
  color: var(--color-primary-dark);
  gap: 16px;
}

/* --- Forms --- */
.site-input,
.site-textarea {
  width: 100%;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 18px 24px;
  color: var(--color-text-dark);
  font-size: 17px;
  background: var(--color-surface-muted);
  transition: all 0.3s ease;
}

.site-input:focus,
.site-textarea:focus {
  outline: none;
  background: #fff;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 6px var(--color-primary-light);
}

.site-field-label {
  display: block;
  margin-bottom: 12px;
  font-size: 16px;
  font-weight: 800;
  color: var(--color-text-dark);
}

.site-field-hint {
  margin-top: 12px;
  font-size: 15px;
  color: var(--color-text-light);
}

/* --- Lists --- */
.site-list {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.site-list-item {
  display: block;
  padding: 40px;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all 0.4s ease;
}

.site-list-item:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
  transform: translateX(12px);
}

.site-list-item__title {
  font-size: 22px;
  font-weight: 800;
  color: var(--color-text-dark);
}

.site-list-item__meta {
  margin-top: 14px;
  font-size: 17px;
  color: var(--color-text-mid);
}

.site-list-item__date {
  font-size: 14px;
  font-weight: 800;
  color: var(--color-primary);
  padding: 8px 20px;
  background: var(--color-primary-light);
  border-radius: 999px;
}

/* --- Utilities --- */
.site-meta-grid {
  display: grid;
  gap: 32px;
}

@media (min-width: 768px) {
  .site-meta-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.site-meta-row {
  padding: 24px 32px;
  background: var(--color-surface-muted);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  transition: all 0.3s ease;
}

.site-meta-row:hover {
  border-color: var(--color-primary-light);
  background: #fff;
  box-shadow: var(--shadow-sm);
}

.site-meta-row__label {
  display: block;
  font-size: 14px;
  font-weight: 800;
  color: var(--color-text-light);
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.site-meta-row__value {
  font-size: 17px;
  font-weight: 800;
  color: var(--color-text-dark);
}

.site-feature-icon {
  width: 64px;
  height: 64px;
  border-radius: 16px;
  background: var(--color-primary-light);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 32px;
  box-shadow: 0 6px 15px rgba(37, 99, 235, 0.1);
}

.site-feature-icon--green { background: #d1fae5; color: #059669; }
.site-feature-icon--violet { background: #ede9fe; color: #7c3aed; }
.site-feature-icon--amber { background: #fef3c7; color: #d97706; }

.site-stat-card {
  text-align: center;
  padding: 56px 40px;
  background: #fff;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}

.site-stat-card__value {
  font-size: 48px;
  font-weight: 900;
  color: var(--color-primary);
  letter-spacing: -0.03em;
}

.site-stat-card__label {
  margin-top: 12px;
  font-size: 16px;
  font-weight: 800;
  color: var(--color-text-mid);
}

.site-category-heading {
  font-size: 32px;
  font-weight: 900;
  color: var(--color-text-dark);
  letter-spacing: -0.04em;
  position: relative;
  padding-left: 24px;
}

.site-category-heading::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 8px;
  height: 40px;
  background: var(--color-primary);
  border-radius: 99px;
}

.site-proof-bar {
  background: var(--color-surface-muted);
  border-block: 1px solid var(--color-border);
}

.site-status {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 8px 20px;
  background: #d1fae5;
  color: #065f46;
  font-size: 14px;
  font-weight: 900;
  border-radius: 999px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.site-message {
  padding: 24px 32px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  font-size: 17px;
  font-weight: 600;
}

.site-message--success {
  background: #d1fae5;
  color: #065f46;
  border-color: #a7f3d0;
}

/* --- CTA --- */
.site-cta {
  padding: 80px;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  color: #fff;
  box-shadow: 0 40px 80px -15px rgba(37, 99, 235, 0.5);
  position: relative;
  overflow: hidden;
}

.site-cta::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(circle at 2px 2px, rgba(255, 255, 255, 0.2) 1px, transparent 0);
  background-size: 48px 48px;
}

/* --- Footer --- */
.site-footer {
  padding-block: 120px 80px;
  border-top: 1px solid var(--color-border);
  background: var(--color-surface-muted);
}

.site-footer__inner {
  display: flex;
  flex-direction: column;
  gap: 80px;
}

.site-footer-tag {
  padding: 8px 20px;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  color: var(--color-text-mid);
  font-size: 14px;
  font-weight: 800;
  box-shadow: var(--shadow-sm);
}

.site-footer-link {
  display: flex;
  align-items: center;
  gap: 14px;
  color: var(--color-text-mid);
  font-weight: 700;
  transition: all 0.3s ease;
}

.site-footer-link:hover {
  color: var(--color-primary);
  transform: translateX(6px);
}

.site-to-top {
  position: fixed;
  right: 48px;
  bottom: 48px;
  z-index: 50;
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: #fff;
  color: var(--color-primary);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(30px);
  transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

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

.site-to-top:hover {
  background: var(--color-primary);
  color: #fff;
  transform: translateY(-6px);
  box-shadow: 0 20px 40px -10px rgba(37, 99, 235, 0.4);
}

.site-loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
  padding: 100px;
  color: var(--color-text-mid);
}

.site-spinner {
  width: 48px;
  height: 48px;
  border: 5px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: site-spin 0.8s linear infinite;
}

@keyframes site-spin {
  to { transform: rotate(360deg); }
}

[data-reveal] {
  opacity: 0;
  transform: translateY(40px);
  transition: all 1s cubic-bezier(0.2, 1, 0.3, 1);
}

[data-reveal].is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (min-width: 1024px) {
  .site-header__inner {
    min-height: 100px;
  }
}