:root {
  --color-primary: #0F4C81;
  --color-primary-light: #1a5fa0;
  --color-primary-dark: #0a3560;
  --color-secondary: #36A2EB;
  --color-secondary-light: #5bb8f0;
  --color-accent: #FF7D00;
  --color-accent-light: #ff9a33;
  --color-accent-dark: #e06e00;
  --color-text-primary: #2D3748;
  --color-text-secondary: #718096;
  --color-text-light: #A0AEC0;
  --color-bg-primary: #FFFFFF;
  --color-bg-secondary: #F7FAFC;
  --color-bg-tertiary: #EDF2F7;
  --color-border: #E2E8F0;
  --color-border-light: #F1F5F9;

  --font-family-cn: "Alibaba PuHuiTi", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei UI", sans-serif;
  --font-family-en: "Inter", "Noto Sans SC", sans-serif;
  --font-family-mono: "JetBrains Mono", monospace;

  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;
  --font-size-6xl: 3.75rem;

  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;

  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  --spacing-4xl: 6rem;
  --spacing-5xl: 8rem;

  --container-max: 1200px;
  --container-wide: 1400px;

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;

  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.08);
  --shadow-xl: 0 20px 25px rgba(0,0,0,0.1);
  --shadow-accent: 0 4px 14px rgba(255,125,0,0.25);

  --transition-fast: 0.15s ease-out;
  --transition-normal: 0.2s ease-out;
  --transition-slow: 0.3s ease-out;
  --transition-slower: 0.5s ease-out;

  --header-height: 72px;
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-fixed: 300;
  --z-modal-backdrop: 400;
  --z-modal: 500;
  --z-tooltip: 600;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-family-cn);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  overflow-x: hidden;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-normal);
}

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

ul, ol {
  list-style: none;
}

button, input, textarea, select {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
  border: none;
  outline: none;
  background: none;
}

button {
  cursor: pointer;
}

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--spacing-xl);
}

.container--wide {
  max-width: var(--container-wide);
}

.section {
  padding: var(--spacing-5xl) 0;
}

.section--sm {
  padding: var(--spacing-4xl) 0;
}

.section__header {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

.section__label {
  display: inline-block;
  font-family: var(--font-family-en);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--spacing-sm);
}

.section__title {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-md);
  line-height: var(--line-height-tight);
}

.section__desc {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  max-width: 640px;
  margin: 0 auto;
  line-height: var(--line-height-relaxed);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: 0.75rem 1.75rem;
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  border-radius: var(--radius-md);
  transition: all var(--transition-normal);
  white-space: nowrap;
  cursor: pointer;
}

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

.btn--primary:hover {
  background: var(--color-accent-light);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(255,125,0,0.35);
}

.btn--primary:active {
  transform: translateY(0);
}

.btn--outline {
  background: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn--outline:hover {
  background: var(--color-primary);
  color: #fff;
}

.btn--ghost {
  background: transparent;
  color: var(--color-primary);
}

.btn--ghost:hover {
  background: rgba(15,76,129,0.08);
}

.btn--lg {
  padding: 1rem 2.25rem;
  font-size: var(--font-size-lg);
  border-radius: var(--radius-lg);
}

.btn--sm {
  padding: 0.5rem 1.25rem;
  font-size: var(--font-size-sm);
}

.card {
  background: var(--color-bg-primary);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  overflow: hidden;
  transition: all var(--transition-slow);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.card__image {
  width: 100%;
  aspect-ratio: 16/10;
  object-fit: cover;
  background: var(--color-bg-tertiary);
}

.card__body {
  padding: var(--spacing-lg);
}

.card__tag {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  color: var(--color-accent);
  background: rgba(255,125,0,0.1);
  border-radius: var(--radius-full);
  margin-bottom: var(--spacing-sm);
}

.card__title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-sm);
  line-height: var(--line-height-tight);
}

.card__desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

.grid {
  display: grid;
  gap: var(--spacing-xl);
}

.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }
.grid--6 { grid-template-columns: repeat(6, 1fr); }

.text-gradient {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.bg-gradient-primary {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
}

.bg-gradient-hero {
  background: linear-gradient(135deg, #0a3560 0%, var(--color-primary) 40%, #1a5fa0 100%);
}

.animate-fade-in-up {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s ease-out, transform 0.7s ease-out;
}

.animate-fade-in-up.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 1023px) {
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
  .grid--6 { grid-template-columns: repeat(3, 1fr); }
  .section { padding: var(--spacing-4xl) 0; }
  .section__title { font-size: var(--font-size-2xl); }
}

@media (max-width: 767px) {
  :root {
    --header-height: 60px;
  }
  .grid--2,
  .grid--3,
  .grid--4,
  .grid--6 { grid-template-columns: 1fr; }
  .section { padding: var(--spacing-3xl) 0; }
  .section__title { font-size: var(--font-size-xl); }
  .section__desc { font-size: var(--font-size-base); }
  .container { padding: 0 var(--spacing-md); }
}