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

:root {
  --bg: #0a0e1a;
  --bg2: #0f1528;
  --bg3: #141c35;
  --accent: #3b82f6;
  --accent2: #6366f1;
  --accent-glow: rgba(59,130,246,0.25);
  --text: #e2e8f0;
  --text-muted: #8892a4;
  --border: rgba(255,255,255,0.07);
  --card-bg: rgba(255,255,255,0.03);
  --radius: 12px;
  --radius-lg: 20px;
}

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  overflow-x: hidden;
}

.container { max-width: 1160px; margin: 0 auto; padding: 0 24px; }

/* ── Header ── */
.header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  padding: 16px 0;
  background: transparent;
  transition: background .3s, border-bottom .3s;
}
.header.scrolled {
  background: rgba(10,14,26,0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.header .container { display: flex; align-items: center; justify-content: space-between; }

.logo { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); }
.logo-icon { width: 36px; height: 36px; flex-shrink: 0; }
.logo-text { display: flex; flex-direction: column; line-height: 1.2; }
.logo-text strong { font-size: 15px; letter-spacing: .5px; }
.logo-text small { font-size: 10px; color: var(--text-muted); letter-spacing: 1.5px; }

.nav { display: flex; gap: 32px; }
.nav a { color: var(--text-muted); text-decoration: none; font-size: 14px; transition: color .2s; }
.nav a:hover { color: var(--text); }

.nav-toggle { display: none; background: none; border: none; color: var(--text); font-size: 22px; cursor: pointer; }

/* ── Hero ── */
.hero {
  position: relative; min-height: 80vh;
  display: flex; align-items: center;
  padding: 100px 0 64px;
  overflow: hidden;
}
.hero-bg {
  position: absolute; inset: 0; z-index: 0;
  background: radial-gradient(ellipse 70% 60% at 70% 50%, rgba(59,130,246,0.12) 0%, transparent 70%),
              radial-gradient(ellipse 40% 40% at 20% 80%, rgba(99,102,241,0.08) 0%, transparent 60%);
}
.hero .container { display: flex; align-items: center; gap: 60px; position: relative; z-index: 1; }

.hero-content { flex: 1; }
.hero-tag {
  display: inline-block; padding: 6px 16px; border-radius: 100px;
  border: 1px solid rgba(59,130,246,0.3);
  color: var(--accent); font-size: 13px; letter-spacing: 1px; margin-bottom: 24px;
}
.hero-content h1 { font-size: clamp(30px, 3.5vw, 46px); font-weight: 700; line-height: 1.25; margin-bottom: 18px; }
.hero-content p { font-size: 15px; color: var(--text-muted); max-width: 480px; margin-bottom: 28px; }
.hero-buttons { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 32px; }

.hero-features { display: grid; grid-template-columns: 1fr 1fr; gap: 12px 24px; }
.hero-feat { display: flex; align-items: center; gap: 10px; font-size: 14px; color: var(--text-muted); }
.feat-dot { width: 6px; height: 6px; min-width: 6px; border-radius: 50%; background: var(--accent); }

.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 13px 28px; border-radius: 8px;
  font-size: 15px; font-weight: 500; text-decoration: none;
  cursor: pointer; border: none; transition: all .2s;
}
.btn-primary {
  background: var(--accent); color: #fff;
  box-shadow: 0 0 24px rgba(59,130,246,0.3);
}
.btn-primary:hover { background: #2563eb; box-shadow: 0 0 32px rgba(59,130,246,0.5); transform: translateY(-1px); }
.btn-outline { background: transparent; color: var(--text); border: 1px solid var(--border); }
.btn-outline:hover { border-color: var(--accent); color: var(--accent); }
.btn-full { width: 100%; justify-content: center; font-size: 16px; padding: 16px; }

/* Code window */
.hero-visual { flex: 1; position: relative; max-width: 480px; }
.code-window {
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: var(--radius-lg); overflow: hidden;
  box-shadow: 0 40px 80px rgba(0,0,0,0.4);
}
.window-bar { display: flex; gap: 7px; padding: 14px 16px; background: var(--bg3); border-bottom: 1px solid var(--border); }
.window-bar span { width: 12px; height: 12px; border-radius: 50%; background: rgba(255,255,255,0.15); }
.window-bar span:nth-child(1) { background: #ff5f57; }
.window-bar span:nth-child(2) { background: #febc2e; }
.window-bar span:nth-child(3) { background: #28c840; }
.code-content { padding: 24px 28px; font-size: 14px; font-family: "SF Mono", Menlo, monospace; line-height: 2; white-space: pre; }
.c-keyword { color: #c792ea; }
.c-var { color: #82aaff; }
.c-fn { color: #82b1ff; }
.c-key { color: #f07178; }
.c-str { color: #c3e88d; }
.c-comment { color: #546e7a; }

.float-card {
  position: absolute; background: var(--bg2); border: 1px solid var(--border);
  border-radius: 10px; padding: 12px 18px; display: flex; align-items: center; gap: 10px;
  font-size: 13px; font-weight: 500; white-space: nowrap;
  box-shadow: 0 8px 32px rgba(0,0,0,0.3);
}
.fc1 { bottom: -20px; left: -20px; }
.fc2 { top: -20px; right: -20px; }
.fc-icon { width: 28px; height: 28px; border-radius: 6px; background: var(--accent-glow); color: var(--accent); display: flex; align-items: center; justify-content: center; font-size: 14px; }

.hero-scroll {
  position: absolute; bottom: 32px; left: 50%; transform: translateX(-50%);
  display: flex; justify-content: center;
}
.hero-scroll span {
  display: block; width: 1px; height: 48px;
  background: linear-gradient(to bottom, transparent, var(--accent), transparent);
  animation: scrollLine 2s infinite;
}
@keyframes scrollLine { 0%,100%{opacity:.2}50%{opacity:1} }

/* ── Stats ── */
.stats {
  background: var(--bg2);
  border-top: 1px solid var(--border); border-bottom: 1px solid var(--border);
  padding: 48px 0;
}
.stats .container { display: flex; gap: 0; }
.stat-item { flex: 1; text-align: center; padding: 0 24px; }
.stat-item + .stat-item { border-left: 1px solid var(--border); }
.stat-num { font-size: 40px; font-weight: 700; color: var(--accent); line-height: 1.1; margin-bottom: 8px; }
.stat-label { color: var(--text-muted); font-size: 14px; }

/* ── Section ── */
.section { padding: 72px 0; }
.section-header { text-align: center; margin-bottom: 60px; }
.section-tag {
  display: inline-block; color: var(--accent); font-size: 13px; letter-spacing: 2px;
  text-transform: uppercase; margin-bottom: 16px;
}
.section-header h2 { font-size: clamp(26px, 3vw, 38px); font-weight: 700; margin-bottom: 16px; }
.section-header p { color: var(--text-muted); font-size: 16px; max-width: 480px; margin: 0 auto; }

/* ── Services ── */
.services { background: var(--bg); }
.services-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }

.service-card {
  background: var(--card-bg); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 32px;
  transition: all .3s;
}
.service-card:hover { border-color: rgba(59,130,246,0.3); background: rgba(59,130,246,0.05); transform: translateY(-4px); }
.service-card.featured { border-color: rgba(59,130,246,0.2); background: linear-gradient(135deg, rgba(59,130,246,0.08), rgba(99,102,241,0.05)); }

.service-card-header { display: flex; align-items: center; gap: 16px; margin-bottom: 16px; }
.service-icon { width: 44px; height: 44px; min-width: 44px; color: var(--accent); }
.service-icon svg { width: 100%; height: 100%; }
.service-card h3 { font-size: 17px; font-weight: 600; }
.service-card p { color: var(--text-muted); font-size: 14px; line-height: 1.75; margin-bottom: 16px; }
.service-list { list-style: none; margin-bottom: 20px; display: flex; flex-direction: column; gap: 8px; }
.service-list li { font-size: 14px; color: var(--text-muted); display: flex; align-items: baseline; gap: 8px; }
.service-list li span { color: var(--accent); font-size: 10px; flex-shrink: 0; }
.service-tags { display: flex; flex-wrap: wrap; gap: 8px; list-style: none; }
.service-tags li {
  padding: 3px 12px; border-radius: 100px;
  background: rgba(59,130,246,0.1); border: 1px solid rgba(59,130,246,0.2);
  color: var(--accent); font-size: 12px;
}

/* ── Process ── */
.process { background: var(--bg2); }
.process-steps { display: flex; align-items: center; justify-content: center; gap: 0; flex-wrap: wrap; }
.process-step { text-align: center; flex: 1; min-width: 160px; padding: 32px 20px; }
.step-num { font-size: 48px; font-weight: 800; color: rgba(59,130,246,0.15); line-height: 1; margin-bottom: 16px; }
.process-step h4 { font-size: 16px; font-weight: 600; margin-bottom: 8px; }
.process-step p { color: var(--text-muted); font-size: 13px; }
.process-arrow { font-size: 24px; color: rgba(59,130,246,0.4); padding: 0 8px; }

/* ── About ── */
.about { background: var(--bg); }
.about-inner { display: flex; align-items: center; gap: 80px; }
.about-visual { flex: 1; }
.about-card {
  background: linear-gradient(135deg, var(--bg2), var(--bg3));
  border: 1px solid var(--border); border-radius: var(--radius-lg);
  padding: 48px 40px; position: relative; overflow: hidden;
}
.about-card-line {
  position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
}
.about-badge {
  display: inline-block; padding: 5px 12px; border-radius: 100px;
  background: rgba(59,130,246,0.1); border: 1px solid rgba(59,130,246,0.2);
  color: var(--accent); font-size: 12px; margin-bottom: 20px;
}
.about-card h3 { font-size: 24px; font-weight: 700; margin-bottom: 8px; }
.about-card p { color: var(--text-muted); font-size: 14px; }
.about-dots { display: flex; gap: 8px; margin-top: 32px; }
.about-dots span { width: 8px; height: 8px; border-radius: 50%; background: var(--accent); opacity: .3; }
.about-dots span:first-child { opacity: 1; }

.about-content { flex: 1.2; }
.about-content h2 { font-size: clamp(26px, 3vw, 38px); font-weight: 700; margin: 16px 0 20px; }
.about-content p { color: var(--text-muted); margin-bottom: 16px; }
.about-values { display: flex; flex-direction: column; gap: 20px; margin-top: 32px; }
.value-item { display: flex; align-items: flex-start; gap: 14px; }
.value-icon { color: var(--accent); font-size: 20px; line-height: 1.6; }
.value-item strong { display: block; margin-bottom: 2px; }
.value-item span { color: var(--text-muted); font-size: 14px; }

/* ── Cases ── */
.cases { background: var(--bg2); }
.cases-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.case-card {
  background: var(--card-bg); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 28px; display: flex; align-items: center; gap: 16px;
  transition: all .3s;
}
.case-card:hover { border-color: rgba(59,130,246,0.3); transform: translateY(-2px); }
.case-card.placeholder { opacity: 0.5; }
.case-logo {
  width: 56px; height: 56px; min-width: 56px; border-radius: 12px;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  display: flex; align-items: center; justify-content: center;
  font-size: 16px; font-weight: 700; color: #fff;
}
.case-card.placeholder .case-logo { background: var(--bg3); color: var(--text-muted); }
.case-info strong { display: block; font-size: 14px; margin-bottom: 4px; }
.case-info span { color: var(--text-muted); font-size: 13px; }

/* ── Contact ── */
.contact { background: var(--bg); }
.contact-inner { display: grid; grid-template-columns: 1fr 1.5fr; gap: 60px; }
.contact-item { display: flex; gap: 16px; align-items: flex-start; margin-bottom: 28px; }
.contact-icon {
  width: 44px; height: 44px; min-width: 44px; border-radius: 10px;
  background: rgba(59,130,246,0.1); border: 1px solid rgba(59,130,246,0.2);
  display: flex; align-items: center; justify-content: center; color: var(--accent);
}
.contact-icon svg { width: 20px; height: 20px; }
.contact-item strong { display: block; font-size: 13px; color: var(--text-muted); margin-bottom: 4px; }
.contact-item span { font-size: 15px; }
.contact-qr {
  margin-top: 12px;
  width: 120px; height: 120px; border-radius: 12px;
  background: var(--bg2); border: 1px dashed var(--border);
  display: flex; align-items: center; justify-content: center;
  color: var(--text-muted); font-size: 13px; text-align: center; line-height: 1.6;
}

.contact-form { background: var(--bg2); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 40px; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.form-group { margin-bottom: 20px; }
.form-group label { display: block; font-size: 13px; color: var(--text-muted); margin-bottom: 8px; }
.form-group input, .form-group textarea {
  width: 100%; background: rgba(255,255,255,0.04); border: 1px solid var(--border);
  border-radius: 8px; padding: 12px 16px; color: var(--text); font-size: 14px;
  font-family: inherit; transition: border-color .2s; outline: none;
}
.form-group input:focus, .form-group textarea:focus { border-color: var(--accent); }
.form-group textarea { resize: vertical; min-height: 120px; }

/* ── Footer ── */
.footer { background: var(--bg2); border-top: 1px solid var(--border); padding: 60px 0 32px; }
.footer-top { display: flex; gap: 80px; margin-bottom: 48px; }
.footer-brand { flex: 1.5; }
.footer-brand p { color: var(--text-muted); font-size: 14px; line-height: 1.8; margin-top: 16px; }
.footer-links { display: flex; gap: 60px; }
.footer-col { display: flex; flex-direction: column; gap: 12px; }
.footer-col strong { font-size: 14px; margin-bottom: 4px; }
.footer-col a { color: var(--text-muted); text-decoration: none; font-size: 14px; transition: color .2s; }
.footer-col a:hover { color: var(--text); }
.footer-bottom {
  display: flex; justify-content: space-between; align-items: center;
  padding-top: 24px; border-top: 1px solid var(--border);
  color: var(--text-muted); font-size: 13px;
}

/* ── Responsive ── */
@media (max-width: 900px) {
  .hero .container { flex-direction: column; }
  .hero-visual { display: none; }
  .stats .container { flex-wrap: wrap; }
  .stat-item { flex: 1 1 45%; border: none; padding: 20px; }
  .services-grid { grid-template-columns: 1fr; }
  .about-inner { flex-direction: column; }
  .contact-inner { grid-template-columns: 1fr; }
  .footer-top { flex-direction: column; gap: 40px; }
}

@media (max-width: 600px) {
  .nav { display: none; }
  .nav.open { display: flex; flex-direction: column; position: absolute; top: 64px; left: 0; right: 0; background: var(--bg2); padding: 20px 24px; border-bottom: 1px solid var(--border); }
  .nav-toggle { display: block; }
  .services-grid { grid-template-columns: 1fr; }
  .cases-grid { grid-template-columns: 1fr; }
  .process-steps { flex-direction: column; }
  .process-arrow { transform: rotate(90deg); }
  .form-row { grid-template-columns: 1fr; }
  .footer-links { flex-direction: column; gap: 32px; }
  .footer-bottom { flex-direction: column; gap: 8px; text-align: center; }
}

/* ── Hero gradient text ── */
.hero h1 .gradient {
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ── Advantages section (核心优势) ── */
.advantages { background: linear-gradient(180deg, var(--bg) 0%, var(--bg2) 100%); }
.advantages-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  margin-top: 48px;
}
.feature-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px 32px;
  position: relative;
  overflow: hidden;
  transition: all .3s;
}
.feature-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent);
  box-shadow: 0 12px 40px rgba(59, 130, 246, 0.15);
}
.feature-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
}
.feature-num {
  font-size: 14px;
  color: var(--accent);
  font-weight: 600;
  letter-spacing: 2px;
  margin-bottom: 8px;
}
.feature-icon {
  font-size: 36px;
  margin-bottom: 16px;
}
.feature-card h3 {
  font-size: 22px;
  margin-bottom: 12px;
  color: var(--text);
}
.feature-card > p {
  color: var(--text-muted);
  margin-bottom: 20px;
  font-size: 14.5px;
}
.feature-list {
  list-style: none;
  padding: 0;
}
.feature-list li {
  padding: 8px 0;
  border-top: 1px solid var(--border);
  font-size: 14px;
  color: var(--text-muted);
  position: relative;
  padding-left: 18px;
}
.feature-list li::before {
  content: '✓';
  color: var(--accent);
  position: absolute;
  left: 0;
  font-weight: 700;
}

/* ── Tech stack (技术栈) ── */
.tech-stacks {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
  margin-top: 48px;
}
.tech-group {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
}
.tech-group h4 {
  font-size: 18px;
  margin-bottom: 16px;
  color: var(--accent);
  display: flex;
  align-items: center;
  gap: 8px;
}
.tech-group h4::before {
  content: '';
  width: 4px; height: 18px;
  background: linear-gradient(180deg, var(--accent), var(--accent2));
  border-radius: 2px;
}
.tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.tech-tag {
  background: rgba(59, 130, 246, 0.08);
  border: 1px solid rgba(59, 130, 246, 0.2);
  color: var(--text);
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 13px;
  transition: all .2s;
}
.tech-tag:hover {
  background: rgba(59, 130, 246, 0.18);
  border-color: var(--accent);
}

/* ── FAQ ── */
.faq { background: linear-gradient(180deg, var(--bg2) 0%, var(--bg) 100%); }
.faq-list {
  max-width: 860px;
  margin: 48px auto 0;
}
.faq-item {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
  transition: all .3s;
}
.faq-item:hover {
  border-color: rgba(59, 130, 246, 0.4);
}
.faq-question {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 24px;
  cursor: pointer;
  font-weight: 500;
  font-size: 16px;
  color: var(--text);
  user-select: none;
}
.faq-question:hover { background: rgba(59, 130, 246, 0.05); }
.faq-toggle {
  width: 28px; height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(59, 130, 246, 0.15);
  color: var(--accent);
  border-radius: 50%;
  font-size: 18px;
  font-weight: 600;
  transition: all .3s;
  flex-shrink: 0;
}
.faq-item.open .faq-toggle {
  transform: rotate(45deg);
  background: var(--accent);
  color: white;
}
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height .4s ease, padding .4s ease;
  padding: 0 24px;
}
.faq-item.open .faq-answer {
  max-height: 400px;
  padding: 0 24px 20px;
}
.faq-answer p {
  color: var(--text-muted);
  font-size: 14.5px;
  line-height: 1.8;
}
.faq-answer p strong {
  color: var(--text);
}

/* ── Form select ── */
.contact-form select {
  width: 100%;
  padding: 12px 14px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-size: 15px;
  font-family: inherit;
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg width='12' height='8' viewBox='0 0 12 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%238892a4' stroke-width='1.5'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 16px center;
  transition: all .2s;
}
.contact-form select:focus {
  outline: none;
  border-color: var(--accent);
  background-color: rgba(59, 130, 246, 0.05);
}
.contact-form select option {
  background: var(--bg2);
  color: var(--text);
}

/* ── Responsive ── */
@media (max-width: 900px) {
  .advantages-grid { grid-template-columns: 1fr; }
  .tech-stacks { grid-template-columns: 1fr; }
}