/* =========================================
   顶简科技 — 官方网站样式
   ========================================= */

/* ---------- 基础变量 ---------- */
:root {
  --c-primary: #2563eb;
  --c-primary-dark: #1d4ed8;
  --c-primary-light: #3b82f6;
  --c-accent: #06b6d4;
  --c-bg: #ffffff;
  --c-bg-alt: #f8fafc;
  --c-bg-dark: #0f172a;
  --c-text: #1e293b;
  --c-text-light: #64748b;
  --c-text-lighter: #94a3b8;
  --c-border: #e2e8f0;
  --c-success: #10b981;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,.06);
  --shadow-md: 0 4px 20px rgba(0,0,0,.08);
  --shadow-lg: 0 8px 40px rgba(0,0,0,.1);
  --shadow-xl: 0 20px 60px rgba(0,0,0,.12);
  --transition: .3s cubic-bezier(.4,0,.2,1);
  --font: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --container: 1200px;
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font);
  color: var(--c-text);
  background: var(--c-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }
img { max-width: 100%; display: block; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }
input, textarea, select { font-family: inherit; font-size: inherit; }

/* ---------- Container ---------- */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Section ---------- */
.section {
  padding: 100px 0;
}
.section-header {
  text-align: center;
  margin-bottom: 60px;
}
.section-tag {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--c-primary);
  margin-bottom: 12px;
}
.section-title {
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 900;
  color: var(--c-text);
  margin-bottom: 16px;
  line-height: 1.3;
}
.section-desc {
  font-size: 17px;
  color: var(--c-text-light);
  max-width: 640px;
  margin: 0 auto;
}

/* ========== 导航栏 ========== */
.header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(255,255,255,.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: var(--transition);
}
.header.scrolled {
  border-bottom-color: var(--c-border);
  box-shadow: var(--shadow-sm);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 18px;
}
.logo-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px; height: 36px;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  color: #fff;
  border-radius: var(--radius-sm);
  font-size: 16px;
  font-weight: 900;
}
.logo-text { color: var(--c-text); }
.nav {
  display: flex;
  align-items: center;
  gap: 6px;
}
.nav-link {
  padding: 8px 16px;
  font-size: 15px;
  font-weight: 500;
  color: var(--c-text-light);
  border-radius: var(--radius-sm);
  transition: var(--transition);
}
.nav-link:hover,
.nav-link.active {
  color: var(--c-primary);
  background: rgba(37,99,235,.06);
}
.nav-link--cta {
  color: #fff !important;
  background: var(--c-primary) !important;
  margin-left: 8px;
}
.nav-link--cta:hover {
  background: var(--c-primary-dark) !important;
}
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 28px;
  padding: 4px 0;
}
.hamburger span {
  display: block;
  height: 2.5px;
  background: var(--c-text);
  border-radius: 2px;
  transition: var(--transition);
}

/* ========== Hero ========== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  background: linear-gradient(160deg, #0f172a 0%, #1e3a5f 40%, #1e40af 100%);
}
.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 50% at 70% 30%, rgba(37,99,235,.3) 0%, transparent 70%),
    radial-gradient(ellipse 40% 40% at 20% 80%, rgba(6,182,212,.25) 0%, transparent 60%);
  animation: heroPulse 8s ease-in-out infinite alternate;
}
@keyframes heroPulse {
  0%   { opacity: .6; }
  100% { opacity: 1; }
}
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' xmlns='http://www.w3.org/2000/svg'%3E%3Cdefs%3E%3Cpattern id='grid' width='60' height='60' patternUnits='userSpaceOnUse'%3E%3Cpath d='M 60 0 L 0 0 0 60' fill='none' stroke='rgba(255,255,255,.04)' stroke-width='1'/%3E%3C/pattern%3E%3C/defs%3E%3Crect width='100%25' height='100%25' fill='url(%23grid)'/%3E%3C/svg%3E");
  pointer-events: none;
}
.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 120px 0 80px;
}
.hero-title {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
  font-size: clamp(32px, 5vw, 56px);
  font-weight: 900;
  color: #fff;
  margin-bottom: 24px;
}
.hero-dot {
  color: var(--c-accent);
  font-size: clamp(28px, 4vw, 48px);
}
.hero-subtitle {
  font-size: clamp(18px, 2.5vw, 24px);
  color: rgba(255,255,255,.9);
  font-weight: 500;
  margin-bottom: 16px;
}
.hero-desc {
  font-size: 16px;
  color: rgba(255,255,255,.6);
  line-height: 1.8;
  margin-bottom: 40px;
}
.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 60px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 32px;
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: var(--transition);
  white-space: nowrap;
}
.btn-primary {
  background: var(--c-primary);
  color: #fff;
  box-shadow: 0 4px 16px rgba(37,99,235,.3);
}
.btn-primary:hover {
  background: var(--c-primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(37,99,235,.4);
}
.btn-outline {
  border: 2px solid rgba(255,255,255,.3);
  color: #fff;
}
.btn-outline:hover {
  border-color: #fff;
  background: rgba(255,255,255,.08);
}
.btn-lg {
  padding: 18px 40px;
  font-size: 16px;
}

/* Hero Stats */
.hero-stats {
  display: flex;
  justify-content: center;
  gap: 48px;
  flex-wrap: wrap;
}
.stat { text-align: center; }
.stat-num {
  display: block;
  font-size: 42px;
  font-weight: 900;
  color: #fff;
  line-height: 1;
}
.stat-plus {
  font-size: 28px;
  font-weight: 700;
  color: var(--c-accent);
}
.stat-label {
  font-size: 14px;
  color: rgba(255,255,255,.5);
  margin-top: 6px;
  display: block;
}

/* Hero scroll indicator */
.hero-scroll {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  color: rgba(255,255,255,.4);
  font-size: 12px;
  letter-spacing: 2px;
}
.scroll-line {
  width: 1px;
  height: 40px;
  background: linear-gradient(to bottom, rgba(255,255,255,.4), transparent);
  animation: scrollDown 1.6s ease-in-out infinite;
}
@keyframes scrollDown {
  0%   { transform: scaleY(0); transform-origin: top; }
  50%  { transform: scaleY(1); transform-origin: top; }
  51%  { transform-origin: bottom; }
  100% { transform: scaleY(0); transform-origin: bottom; }
}

/* ========== Products ========== */
.services { background: var(--c-bg); }

.product-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-bottom: 60px;
}
.product-card {
  background: var(--c-bg);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 36px 28px 28px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}
.product-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--c-primary), var(--c-accent));
  opacity: 0;
  transition: var(--transition);
}
.product-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}
.product-card:hover::before { opacity: 1; }

.product-icon {
  width: 56px; height: 56px;
  color: var(--c-primary);
  margin-bottom: 20px;
}
.product-icon svg { width: 100%; height: 100%; }

.product-title {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 10px;
}
.product-desc {
  font-size: 14px;
  color: var(--c-text-light);
  margin-bottom: 16px;
  line-height: 1.7;
}
.product-tags {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.product-tags li {
  padding: 4px 12px;
  font-size: 12px;
  font-weight: 600;
  background: rgba(37,99,235,.06);
  color: var(--c-primary);
  border-radius: 20px;
}

/* Sub products */
.sub-products {
  background: var(--c-bg-alt);
  border-radius: var(--radius-lg);
  padding: 40px;
}
.sub-products-title {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 28px;
  text-align: center;
}
.sub-product-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.sub-product-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 16px;
  background: var(--c-bg);
  border-radius: var(--radius-md);
  transition: var(--transition);
}
.sub-product-item:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}
.sub-product-icon {
  font-size: 24px;
  flex-shrink: 0;
  line-height: 1;
}
.sub-product-item strong {
  font-size: 15px;
  display: block;
  margin-bottom: 4px;
}
.sub-product-item p {
  font-size: 13px;
  color: var(--c-text-light);
  margin: 0;
}

/* ========== Solutions ========== */
.solutions {
  background: var(--c-bg-alt);
}
.solution-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  margin-bottom: 40px;
}
.solution-tab {
  padding: 10px 24px;
  font-size: 14px;
  font-weight: 600;
  border-radius: 40px;
  color: var(--c-text-light);
  border: 1px solid var(--c-border);
  background: var(--c-bg);
  transition: var(--transition);
}
.solution-tab:hover {
  color: var(--c-primary);
  border-color: var(--c-primary-light);
}
.solution-tab.active {
  background: var(--c-primary);
  color: #fff;
  border-color: var(--c-primary);
}

.solution-panels { position: relative; }
.solution-panel {
  display: none;
  gap: 48px;
  align-items: flex-start;
  animation: fadeIn .4s ease;
}
.solution-panel.active {
  display: grid;
  grid-template-columns: 1fr 360px;
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

.solution-info h3 {
  font-size: 26px;
  font-weight: 800;
  margin-bottom: 8px;
}
.solution-clients {
  font-size: 14px;
  color: var(--c-primary);
  font-weight: 600;
  margin-bottom: 24px;
}
.solution-features {
  display: flex;
  flex-direction: column;
  gap: 14px;
}
.solution-features li {
  font-size: 15px;
  color: var(--c-text-light);
  padding-left: 20px;
  position: relative;
}
.solution-features li::before {
  content: '';
  position: absolute;
  left: 0; top: 10px;
  width: 8px; height: 8px;
  background: var(--c-primary);
  border-radius: 50%;
}
.solution-features li strong {
  color: var(--c-text);
}

.solution-visual {
  display: flex;
  justify-content: center;
  align-items: flex-start;
}
.solution-mockup {
  width: 320px;
  perspective: 800px;
}
.mockup-screen {
  background: var(--c-bg);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  overflow: hidden;
  padding: 0;
  transform: rotateY(-6deg) rotateX(2deg);
  transition: var(--transition);
}
.mockup-screen:hover {
  transform: rotateY(0) rotateX(0);
}
.mockup-header {
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  color: #fff;
  padding: 24px;
  font-size: 18px;
  font-weight: 700;
}
.mockup-items {
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.mockup-item {
  height: 48px;
  background: var(--c-bg-alt);
  border-radius: var(--radius-sm);
  animation: pulse 2s ease-in-out infinite;
}
.mockup-item:nth-child(2) { animation-delay: .3s; width: 85%; }
.mockup-item:nth-child(3) { animation-delay: .6s; width: 70%; }
@keyframes pulse {
  0%, 100% { opacity: .5; }
  50%      { opacity: 1; }
}

/* ========== Advantages ========== */
.advantages { background: var(--c-bg); }
.advantage-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}
.advantage-card {
  padding: 40px 36px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--c-border);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}
.advantage-card:hover {
  border-color: transparent;
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}
.advantage-num {
  font-size: 48px;
  font-weight: 900;
  color: rgba(37,99,235,.08);
  line-height: 1;
  margin-bottom: 12px;
}
.advantage-card h3 {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 10px;
}
.advantage-card p {
  font-size: 15px;
  color: var(--c-text-light);
  line-height: 1.8;
}

/* ========== Clients ========== */
.clients { background: var(--c-bg-alt); }
.client-categories {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  margin-bottom: 36px;
}
.client-cat {
  padding: 8px 20px;
  font-size: 13px;
  font-weight: 600;
  border-radius: 40px;
  color: var(--c-text-light);
  border: 1px solid var(--c-border);
  background: var(--c-bg);
  transition: var(--transition);
}
.client-cat:hover { color: var(--c-primary); border-color: var(--c-primary-light); }
.client-cat.active {
  background: var(--c-primary);
  color: #fff;
  border-color: var(--c-primary);
}

.client-logos {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 16px;
}
.client-logo {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px 16px;
  background: var(--c-bg);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-md);
  font-size: 14px;
  font-weight: 600;
  color: var(--c-text-light);
  transition: var(--transition);
  text-align: center;
}
.client-logo:hover {
  border-color: var(--c-primary-light);
  color: var(--c-primary);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}
.client-logo.hidden { display: none; }

/* ========== About ========== */
.about { background: var(--c-bg); }
.about-inner {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: 60px;
  align-items: center;
}
.about-text p {
  font-size: 16px;
  color: var(--c-text-light);
  margin-bottom: 16px;
  line-height: 1.8;
}
.about-highlights {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-top: 28px;
}
.about-hl {
  padding: 16px 20px;
  background: var(--c-bg-alt);
  border-radius: var(--radius-md);
}
.about-hl strong {
  display: block;
  font-size: 15px;
  margin-bottom: 4px;
}
.about-hl span {
  font-size: 13px;
  color: var(--c-text-light);
}

.about-visual {
  display: flex;
  justify-content: center;
}
.about-card-stack {
  position: relative;
  width: 280px;
  height: 320px;
}
.about-fcard {
  position: absolute;
  width: 200px;
  padding: 40px 28px;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  color: #fff;
  font-size: 22px;
  font-weight: 900;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  text-align: center;
  transition: var(--transition);
}
.about-fcard:nth-child(1) { top: 0; left: 0; z-index: 4; transform: rotate(-3deg); }
.about-fcard:nth-child(2) { top: 30px; left: 40px; z-index: 3; transform: rotate(2deg); background: linear-gradient(135deg, #1d4ed8, #2563eb); }
.about-fcard:nth-child(3) { top: 60px; left: 80px; z-index: 2; transform: rotate(-1deg); background: linear-gradient(135deg, #0891b2, #06b6d4); }
.about-fcard:nth-child(4) { top: 90px; left: 40px; z-index: 1; transform: rotate(3deg); background: linear-gradient(135deg, #059669, #10b981); }
.about-card-stack:hover .about-fcard:nth-child(1) { transform: rotate(0) translateX(-40px) translateY(-20px); }
.about-card-stack:hover .about-fcard:nth-child(2) { transform: rotate(0) translateX(40px) translateY(-10px); }
.about-card-stack:hover .about-fcard:nth-child(3) { transform: rotate(0) translateX(-20px) translateY(30px); }
.about-card-stack:hover .about-fcard:nth-child(4) { transform: rotate(0) translateX(60px) translateY(40px); }

/* ========== Cooperation ========== */
.cooperation {
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  color: #fff;
  text-align: center;
}
.cooperation h2 {
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 900;
  margin-bottom: 16px;
}
.cooperation p {
  font-size: 17px;
  opacity: .85;
  margin-bottom: 32px;
  line-height: 1.8;
}
.cooperation .btn-primary {
  background: #fff;
  color: var(--c-primary);
  box-shadow: 0 4px 20px rgba(0,0,0,.15);
}
.cooperation .btn-primary:hover {
  background: #f0f0f0;
}

/* ========== Contact ========== */
.contact { background: var(--c-bg-alt); }
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: 48px;
  align-items: flex-start;
}
.contact-form {
  background: var(--c-bg);
  padding: 40px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}
.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}
.form-group {
  margin-bottom: 20px;
}
.form-group label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--c-text);
}
.required { color: #ef4444; }
.form-group input,
.form-group textarea {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--c-border);
  border-radius: var(--radius-sm);
  background: var(--c-bg);
  color: var(--c-text);
  transition: var(--transition);
  outline: none;
}
.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--c-primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,.1);
}
.form-group textarea { resize: vertical; min-height: 100px; }
.btn-submit { width: 100%; margin-top: 4px; }
.form-note {
  text-align: center;
  margin-top: 16px;
  font-size: 13px;
  color: var(--c-text-lighter);
}

.contact-info-card {
  background: var(--c-bg);
  padding: 32px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  margin-bottom: 24px;
}
.contact-info-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 20px;
}
.contact-details li {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  margin-bottom: 18px;
}
.contact-details li:last-child { margin-bottom: 0; }
.ci-icon { font-size: 20px; flex-shrink: 0; line-height: 1.5; }
.contact-details strong {
  font-size: 14px;
  display: block;
  margin-bottom: 2px;
}
.contact-details p {
  font-size: 14px;
  color: var(--c-text-light);
  margin: 0;
}

.contact-qr {
  display: flex;
  justify-content: center;
}
.qr-placeholder {
  width: 160px;
  height: 160px;
  border: 2px dashed var(--c-border);
  border-radius: var(--radius-md);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  color: var(--c-text-light);
  font-weight: 600;
  background: var(--c-bg);
}
.qr-placeholder small {
  font-size: 12px;
  font-weight: 400;
  color: var(--c-text-lighter);
}

/* ========== Footer ========== */
.footer {
  background: var(--c-bg-dark);
  color: rgba(255,255,255,.7);
  padding-top: 60px;
}
.footer-inner {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 40px;
}
.footer-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}
.footer-logo .logo-text { color: #fff; }
.footer-about {
  font-size: 14px;
  line-height: 1.8;
}
.footer-col h4 {
  color: #fff;
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 16px;
}
.footer-col a,
.footer-col span {
  display: block;
  font-size: 14px;
  margin-bottom: 10px;
  transition: var(--transition);
}
.footer-col a:hover { color: var(--c-accent); }

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.08);
  padding: 20px 0;
  text-align: center;
  font-size: 13px;
  color: rgba(255,255,255,.4);
}

/* ========== Back to top ========== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 48px; height: 48px;
  background: var(--c-primary);
  color: #fff;
  font-size: 20px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  opacity: 0;
  transform: translateY(20px);
  transition: var(--transition);
  z-index: 900;
}
.back-to-top.visible {
  opacity: 1;
  transform: translateY(0);
}
.back-to-top:hover {
  background: var(--c-primary-dark);
  transform: translateY(-3px);
}

/* ========== Animations (Scroll Reveal) ========== */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity .6s ease, transform .6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ========== 响应式 ========== */
@media (max-width: 1024px) {
  .product-grid { grid-template-columns: repeat(2, 1fr); }
  .sub-product-list { grid-template-columns: repeat(2, 1fr); }
  .advantage-grid { grid-template-columns: 1fr; }
  .about-inner { grid-template-columns: 1fr; }
  .about-visual { display: none; }
  .solution-panel.active { grid-template-columns: 1fr; }
  .solution-visual { display: none; }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .section { padding: 64px 0; }
  .section-header { margin-bottom: 40px; }

  /* Nav */
  .hamburger { display: flex; }
  .nav {
    position: fixed;
    top: 72px; left: 0; right: 0;
    background: var(--c-bg);
    flex-direction: column;
    padding: 16px;
    gap: 4px;
    box-shadow: var(--shadow-lg);
    transform: translateY(-120%);
    transition: var(--transition);
    border-bottom: 1px solid var(--c-border);
  }
  .nav.open {
    transform: translateY(0);
  }
  .nav-link { width: 100%; text-align: center; }
  .nav-link--cta { margin-left: 0; }

  /* Hero */
  .hero-title { flex-direction: column; gap: 4px; }
  .hero-dot { display: none; }
  .hero-stats { gap: 24px; }
  .stat-num { font-size: 32px; }

  /* Products */
  .product-grid { grid-template-columns: 1fr; }
  .sub-product-list { grid-template-columns: 1fr; }
  .sub-products { padding: 24px; }

  /* Solutions */
  .solution-tabs { gap: 6px; }
  .solution-tab { padding: 8px 16px; font-size: 13px; }

  /* Client logos */
  .client-logos { grid-template-columns: repeat(3, 1fr); }

  /* Contact */
  .form-row { grid-template-columns: 1fr; }
  .contact-form { padding: 24px; }

  /* Footer */
  .footer-inner { grid-template-columns: 1fr; gap: 28px; }
}

@media (max-width: 480px) {
  .client-logos { grid-template-columns: repeat(2, 1fr); }
  .hero-stats { gap: 16px; }
  .stat { min-width: 70px; }
}