:root {
  --color-primary: #0b5cff;
  --color-primary-dark: #0946c4;
  --color-primary-light: #3b82ff;
  --color-accent: #00d4ff;
  --color-bg: #ffffff;
  --color-bg-soft: #f6f8fc;
  --color-bg-dark: #0a1a3a;
  --color-text: #1a2238;
  --color-text-soft: #5b6478;
  --color-text-muted: #8a93a6;
  --color-border: #e4e8f0;
  --color-white: #ffffff;
  --gradient-hero: linear-gradient(135deg, #0a1a3a 0%, #0b3a8a 50%, #0b5cff 100%);
  --gradient-accent: linear-gradient(135deg, #0b5cff 0%, #00d4ff 100%);
  --shadow-sm: 0 2px 8px rgba(11, 92, 255, 0.08);
  --shadow-md: 0 8px 24px rgba(11, 92, 255, 0.12);
  --shadow-lg: 0 16px 40px rgba(11, 92, 255, 0.18);
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-pill: 999px;
  --container-max: 1200px;
  --header-height: 72px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Roboto, "Helvetica Neue", Arial, sans-serif;
  --container-padding: clamp(16px, 4vw, 32px);
  --section-padding-y: clamp(56px, 8vw, 96px);
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;
}

@media (min-width: 1601px) {
  :root { --container-max: 1400px; }
}
@media (max-width: 1280px) {
  :root { --container-max: 1200px; }
}
@media (max-width: 960px) {
  :root { --container-max: 960px; }
}
@media (max-width: 640px) {
  :root { --container-max: 100%; }
}

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

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

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  color: var(--color-text);
  background: var(--color-bg);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

ul,
ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.25;
  color: var(--color-text);
}

h1 { font-size: clamp(1.75rem, 2.5rem + 1vw, 3rem); }
h2 { font-size: clamp(1.5rem, 1.5rem + 1vw, 2.25rem); }
h3 { font-size: clamp(1.15rem, 1.1rem + 0.5vw, 1.5rem); }

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

.section {
  padding: var(--section-padding-y) 0;
}

.section--soft {
  background: var(--color-bg-soft);
}

.section--dark {
  background: var(--color-bg-dark);
  color: var(--color-white);
}

.section--dark h2,
.section--dark h3 {
  color: var(--color-white);
}

.section__head {
  text-align: center;
  max-width: min(720px, 100%);
  margin: 0 auto clamp(36px, 5vw, 56px);
}

.section__eyebrow {
  display: inline-block;
  font-size: clamp(0.78rem, 0.75rem + 0.1vw, 0.85rem);
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-primary);
  background: rgba(11, 92, 255, 0.08);
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  margin-bottom: 16px;
}

.section--dark .section__eyebrow {
  color: var(--color-accent);
  background: rgba(0, 212, 255, 0.12);
}

.section__title {
  margin-bottom: 16px;
}

.section__desc {
  color: var(--color-text-soft);
  font-size: clamp(0.95rem, 0.9rem + 0.3vw, 1.05rem);
}

.section--dark .section__desc {
  color: rgba(255, 255, 255, 0.75);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

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

@media (max-width: 768px) {
  .section__head { margin-bottom: 36px; }
}