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

:root {
  --color-bg: #0f1117;
  --color-surface: #161822;
  --color-surface-raised: #1d1f2e;
  --color-border: #252838;
  --color-border-light: #2e3142;
  --color-text: #e4e6f0;
  --color-text-muted: #8b8fa8;
  --color-text-dim: #5c6080;
  --color-primary: #3b82f6;
  --color-primary-hover: #2563eb;
  --color-primary-glow: rgba(59, 130, 246, 0.15);
  --color-accent: #06b6d4;
  --color-accent-glow: rgba(6, 182, 212, 0.12);
  --color-white: #ffffff;
  --color-success: #10b981;

  --font-body: 'Noto Sans SC', 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;

  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.5);
  --shadow-glow: 0 0 40px var(--color-primary-glow);

  --max-width: 1200px;
  --header-h: 64px;
}

html { scroll-behavior: smooth; scroll-padding-top: var(--header-h); }

body {
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img { max-width: 100%; display: block; }
button { cursor: pointer; font: inherit; border: none; background: none; color: inherit; }
input, select, textarea { font: inherit; color: inherit; }

.header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  background: rgba(15, 17, 23, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
  transition: border-color 0.3s;
}
.header.scrolled { border-bottom-color: var(--color-border-light); }

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}
.logo-icon { width: auto; height: 36px; border-radius: 4px; }
.logo-text-accent { color: var(--color-primary); }

.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}
.nav-link {
  padding: 8px 16px;
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-muted);
  transition: color 0.2s, background 0.2s;
}
.nav-link:hover, .nav-link.active { color: var(--color-white); }
.nav-link.active { background: var(--color-surface-raised); }
.nav-link-cta {
  background: var(--color-primary);
  color: var(--color-white) !important;
  margin-left: 8px;
}
.nav-link-cta:hover { background: var(--color-primary-hover); }

.nav-toggle { display: none; flex-direction: column; gap: 5px; padding: 8px; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--color-text); border-radius: 2px; transition: transform 0.3s, opacity 0.3s; }

.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 24px 80px;
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 50% at 50% 0%, rgba(59, 130, 246, 0.08), transparent),
    radial-gradient(ellipse 40% 40% at 80% 80%, rgba(6, 182, 212, 0.05), transparent);
}
.hero-bg::after {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background-image:
    linear-gradient(rgba(37, 40, 56, 0.3) 1px, transparent 1px),
    linear-gradient(90deg, rgba(37, 40, 56, 0.3) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse at center, black 30%, transparent 70%);
}

.hero-content { position: relative; z-index: 1; max-width: 800px; }

.hero-title { font-size: clamp(2.4rem, 6vw, 4rem); font-weight: 700; line-height: 1.15; margin-bottom: 24px; }
.hero-title-line { display: block; }
.hero-title-accent {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  line-height: 1.75;
  margin-bottom: 40px;
}

.hero-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-weight: 600;
  transition: all 0.2s;
  white-space: nowrap;
}
.btn-primary {
  background: var(--color-primary);
  color: var(--color-white);
  box-shadow: 0 0 20px var(--color-primary-glow);
}
.btn-primary:hover { background: var(--color-primary-hover); transform: translateY(-1px); box-shadow: 0 4px 24px var(--color-primary-glow); }
.btn-outline {
  border: 1px solid var(--color-border-light);
  color: var(--color-text);
}
.btn-outline:hover { border-color: var(--color-primary); color: var(--color-primary); background: var(--color-primary-glow); }
.btn-full { width: 100%; }

.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

section { padding: 100px 0; }

.section-header {
  text-align: center;
  margin-bottom: 60px;
}
.section-tag {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-primary);
  background: var(--color-primary-glow);
  padding: 4px 12px;
  border-radius: 20px;
  margin-bottom: 16px;
}
.section-title { font-size: clamp(1.8rem, 3.5vw, 2.4rem); font-weight: 700; margin-bottom: 12px; }
.section-desc { color: var(--color-text-muted); font-size: 1rem; max-width: 560px; margin: 0 auto; }

.services { background: var(--color-surface); }
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.service-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px;
  transition: border-color 0.3s, transform 0.3s, box-shadow 0.3s;
}
.service-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.service-icon { margin-bottom: 20px; color: var(--color-primary); }
.service-card-title { font-size: 1.2rem; font-weight: 700; margin-bottom: 10px; }
.service-card-desc { color: var(--color-text-muted); font-size: 0.9rem; line-height: 1.7; margin-bottom: 16px; }
.service-card-tags { display: flex; flex-wrap: wrap; gap: 6px; }
.service-card-tags li {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text-muted);
  background: var(--color-surface-raised);
  padding: 3px 10px;
  border-radius: var(--radius-sm);
}

.cases { background: var(--color-bg); }
.cases-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.case-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color 0.3s, transform 0.3s;
}
.case-card:hover { border-color: var(--color-border-light); transform: translateY(-2px); }
.case-card-visual {
  height: 120px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}
.case-visual-1 { background: linear-gradient(135deg, #1e3a5f, #162240); }
.case-visual-2 { background: linear-gradient(135deg, #1a3a2a, #0f2420); }
.case-visual-3 { background: linear-gradient(135deg, #3a1e4f, #241640); }
.case-card-icon { color: rgba(255,255,255,0.5); }
.case-card-body { padding: 24px; }
.case-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-accent);
  margin-bottom: 8px;
}
.case-card-title { font-size: 1.05rem; font-weight: 700; margin-bottom: 8px; }
.case-card-desc { color: var(--color-text-muted); font-size: 0.88rem; line-height: 1.65; }

.why-us { background: var(--color-surface); }
.why-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.why-item {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: border-color 0.3s;
}
.why-item:hover { border-color: var(--color-primary); }
.why-number {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-primary);
  margin-bottom: 12px;
}
.why-item h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 8px; }
.why-item p { color: var(--color-text-muted); font-size: 0.88rem; line-height: 1.6; }

.about { background: var(--color-bg); }
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}
.about-text { max-width: 540px; }
.about-text .section-tag { margin-bottom: 12px; }
.about-text .section-title { margin-bottom: 20px; }
.about-text p { color: var(--color-text-muted); font-size: 0.95rem; line-height: 1.75; margin-bottom: 16px; }
.about-stats {
  display: flex;
  gap: 40px;
  margin-top: 32px;
}
.about-stat-num {
  display: block;
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-white);
}
.about-stat-label { font-size: 0.85rem; color: var(--color-text-muted); }
.about-visual { display: flex; justify-content: center; }
.about-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: 48px;
  text-align: center;
  max-width: 320px;
}
.about-card-icon { color: var(--color-primary); margin-bottom: 20px; }
.about-card-text {
  font-size: 1.4rem;
  font-weight: 700;
  line-height: 1.5;
  color: var(--color-white);
}

.contact { background: var(--color-surface); }
.contact-grid {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 40px;
  align-items: start;
}
.contact-info {
  display: flex;
  flex-direction: column;
  gap: 20px;
  padding: 32px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
}
.contact-info-item {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}
.contact-info-item svg { color: var(--color-primary); flex-shrink: 0; }

.contact-form {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.form-field { display: flex; flex-direction: column; gap: 6px; }
.form-field label { font-size: 0.85rem; font-weight: 500; color: var(--color-text-muted); }
.form-field input,
.form-field select,
.form-field textarea {
  padding: 10px 14px;
  background: var(--color-surface-raised);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  color: var(--color-text);
  transition: border-color 0.2s;
  outline: none;
}
.form-field input:focus,
.form-field select:focus,
.form-field textarea:focus {
  border-color: var(--color-primary);
}
.form-field input::placeholder,
.form-field textarea::placeholder { color: var(--color-text-dim); }
.form-field select { appearance: none; background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath d='M2 4l4 4 4-4' fill='none' stroke='%238b8fa8' stroke-width='1.5' stroke-linecap='round'/%3E%3C/svg%3E"); background-repeat: no-repeat; background-position: right 12px center; padding-right: 36px; }

.footer {
  background: var(--color-bg);
  border-top: 1px solid var(--color-border);
  padding: 60px 0 0;
}
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px 40px;
  display: flex;
  justify-content: space-between;
  gap: 60px;
}
.footer-brand { max-width: 280px; }
.footer-logo { font-size: 1.2rem; font-weight: 700; }
.footer-tagline { color: var(--color-text-muted); font-size: 0.88rem; margin-top: 8px; }
.footer-links { display: flex; gap: 60px; }
.footer-col h4 { font-size: 0.85rem; font-weight: 600; color: var(--color-text-muted); margin-bottom: 12px; }
.footer-col a {
  display: block;
  font-size: 0.88rem;
  color: var(--color-text-dim);
  padding: 4px 0;
  transition: color 0.2s;
}
.footer-col a:hover { color: var(--color-text); }
.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding: 20px 24px;
  text-align: center;
  font-size: 0.8rem;
  color: var(--color-text-dim);
}
.footer-icp { margin-top: 6px; }
.footer-icp a { color: var(--color-text-dim); transition: color 0.2s; }
.footer-icp a:hover { color: var(--color-text-muted); }

.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: var(--color-surface-raised);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all 0.3s;
  z-index: 90;
}
.back-to-top.visible { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { color: var(--color-primary); border-color: var(--color-primary); }

@media (max-width: 900px) {
  .services-grid, .cases-grid { grid-template-columns: 1fr; }
  .why-grid { grid-template-columns: repeat(2, 1fr); }
  .about-grid { grid-template-columns: 1fr; gap: 40px; }
  .contact-grid { grid-template-columns: 1fr; }

  .nav-list {
    position: fixed;
    top: var(--header-h);
    left: 0; right: 0;
    bottom: 0;
    background: var(--color-bg);
    flex-direction: column;
    padding: 32px 24px;
    gap: 8px;
    transform: translateX(100%);
    transition: transform 0.3s;
  }
  .nav-list.open { transform: translateX(0); }
  .nav-link { font-size: 1.1rem; padding: 12px 16px; width: 100%; }
  .nav-link-cta { margin-left: 0; margin-top: 8px; text-align: center; }
  .nav-toggle { display: flex; }

  .form-row { grid-template-columns: 1fr; }
}

@media (max-width: 560px) {
  .hero-title { font-size: 2rem; }
  .hero-desc { font-size: 0.95rem; }
  .why-grid { grid-template-columns: 1fr; }
  .about-stats { gap: 24px; }
  .about-stat-num { font-size: 1.6rem; }
  .footer-inner { flex-direction: column; gap: 32px; }
  .footer-links { gap: 40px; }
}