/* ============================================
   LISHI LASER Mixed Gas Device - Light Theme
   ============================================ */

/* CSS Variables - Light Theme */
:root {
  --color-bg: #f8fafc;
  --color-bg-alt: #ffffff;
  --color-surface: #ffffff;
  --color-surface-2: #f1f5f9;
  --color-border: #e2e8f0;
  --color-primary: #2563eb;
  --color-primary-light: #3b82f6;
  --color-primary-dark: #1d4ed8;
  --color-accent: #0891b2;
  --color-accent-light: #06b6d4;
  --color-text: #0f172a;
  --color-text-muted: #475569;
  --color-text-dim: #94a3b8;
  --color-success: #16a34a;
  --color-warning: #d97706;
  --color-danger: #dc2626;
  --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --radius: 8px;
  --radius-lg: 16px;
  --transition: 0.3s ease;
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 40px rgba(0,0,0,0.08);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

/* Typography */
h1, h2, h3, h4 {
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text);
}

h1 { font-size: clamp(2.5rem, 5vw, 4rem); }
h2 { font-size: clamp(1.75rem, 3vw, 2.5rem); }
h3 { font-size: clamp(1.25rem, 2vw, 1.5rem); }

p { color: var(--color-text-muted); }

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

a:hover {
  color: var(--color-primary-dark);
}

/* Container */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================
   HEADER / NAV
   ============================================ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: #ffffff;
  border-bottom: 1px solid #e2e8f0;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo img {
  width: auto;
  height: 50px;
  object-fit: contain;
}

.logo-text {
  display: flex;
  flex-direction: column;
}

.logo-brand {
  font-size: 1.1rem;
  font-weight: 800;
  color: #dc2626;
  letter-spacing: 0.5px;
}

.logo-tagline {
  font-size: 0.7rem;
  color: #dc2626;
  letter-spacing: 1px;
  text-transform: uppercase;
  opacity: 0.8;
}

.nav {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav a {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 8px 14px;
  border-radius: var(--radius);
  transition: all var(--transition);
}

.nav a:hover,
.nav a.active {
  color: var(--color-primary);
  background: transparent;
}

.nav-cta {
  background: var(--color-primary) !important;
  color: white !important;
  margin-left: 8px;
}

.nav-cta:hover {
  background: var(--color-primary) !important;
  color: white !important;
  opacity: 0.9;
}

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-text);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 8px;
}

/* ============================================
   HERO
   ============================================ */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: 80px;
  position: relative;
  overflow: hidden;
  background: linear-gradient(180deg, #f8fafc 0%, #e0f2fe 100%);
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background:
    radial-gradient(ellipse 80% 60% at 20% 20%, rgba(37, 99, 235, 0.06), transparent),
    radial-gradient(ellipse 60% 40% at 80% 80%, rgba(8, 145, 178, 0.05), transparent);
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.hero-content {
  position: relative;
  z-index: 1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: white;
  border: 1px solid var(--color-border);
  padding: 8px 16px;
  border-radius: 50px;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 24px;
  box-shadow: var(--shadow);
}

.hero-badge span {
  color: var(--color-primary);
  font-weight: 600;
}

.hero h1 {
  margin-bottom: 16px;
}

.hero h1 .accent {
  color: var(--color-primary);
}

.hero-subtitle {
  font-size: 1.2rem;
  color: var(--color-text-muted);
  margin-bottom: 32px;
  max-width: 500px;
  line-height: 1.7;
}

.hero-stats {
  display: flex;
  gap: 40px;
  margin-bottom: 40px;
}

.hero-stat {
  text-align: left;
}

.hero-stat-value {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--color-primary);
  line-height: 1;
}

.hero-stat-label {
  font-size: 0.85rem;
  color: var(--color-text-dim);
  margin-top: 4px;
}

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

.hero-visual {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-image {
  width: 100%;
  max-width: 500px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--color-border);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
  text-decoration: none;
}

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

.btn-primary:hover {
  background: var(--color-primary-dark);
  color: white;
  transform: translateY(-2px);
  box-shadow: 0 10px 30px rgba(37, 99, 235, 0.3);
}

.btn-secondary {
  background: white;
  color: var(--color-text);
  border: 1.5px solid var(--color-border);
}

.btn-secondary:hover {
  background: var(--color-surface-2);
  color: var(--color-primary);
  border-color: var(--color-primary);
}

/* ============================================
   SECTIONS
   ============================================ */
.section {
  padding: 100px 0;
}

.section-alt {
  background: var(--color-surface-2);
}

.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 64px;
}

.section-header p {
  margin-top: 16px;
  font-size: 1.1rem;
  color: var(--color-text-muted);
}

.section-label {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: var(--color-primary);
  margin-bottom: 12px;
}

/* ============================================
   WHAT IS MIXED GAS
   ============================================ */
.principle-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.principle-visual {
  position: relative;
}

.flow-diagram {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow);
}

.flow-step {
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 20px 0;
  border-bottom: 1px solid var(--color-border);
}

.flow-step:last-child {
  border-bottom: none;
}

.flow-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  flex-shrink: 0;
  color: white;
}

.flow-content h4 {
  font-size: 1.1rem;
  margin-bottom: 4px;
}

.flow-content p {
  font-size: 0.9rem;
  color: var(--color-text-dim);
}

.flow-arrow {
  text-align: center;
  padding: 8px 0;
  color: var(--color-primary);
  font-size: 1.5rem;
}

.principle-features {
  display: grid;
  gap: 24px;
}

.feature-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px;
  transition: all var(--transition);
  box-shadow: var(--shadow);
}

.feature-card:hover {
  border-color: var(--color-primary-light);
  transform: translateX(8px);
  box-shadow: var(--shadow-lg);
}

.feature-card h4 {
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.feature-icon {
  width: 40px;
  height: 40px;
  border-radius: 8px;
  background: rgba(37, 99, 235, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
}

/* ============================================
   ADVANTAGES
   ============================================ */
.advantage-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.advantage-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px;
  text-align: center;
  transition: all var(--transition);
  box-shadow: var(--shadow);
}

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

.advantage-icon {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.1), rgba(8, 145, 178, 0.1));
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
  font-size: 1.75rem;
}

.advantage-card h3 {
  font-size: 1.15rem;
  margin-bottom: 12px;
}

.advantage-card p {
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

.advantage-highlight {
  color: var(--color-success);
  font-weight: 600;
}

/* Comparison Table */
.comparison-section {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 40px;
  margin-top: 48px;
  overflow-x: auto;
  box-shadow: var(--shadow);
}

.comparison-section h3 {
  margin-bottom: 24px;
  text-align: center;
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 600px;
}

.comparison-table th,
.comparison-table td {
  padding: 16px 20px;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

.comparison-table th {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--color-text-dim);
  font-weight: 600;
  background: var(--color-surface-2);
}

.comparison-table td {
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

.comparison-table tr:last-child td {
  border-bottom: none;
}

.comparison-win {
  color: var(--color-success);
  font-weight: 600;
}

/* ============================================
   CUTTING PARAMETERS
   ============================================ */
.params-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.params-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow);
}

.params-card h3 {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 20px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--color-border);
}

.params-power {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  color: white;
  padding: 4px 12px;
  border-radius: 50px;
  font-size: 0.85rem;
  font-weight: 600;
}

.params-table {
  width: 100%;
}

.params-table th,
.params-table td {
  padding: 10px 0;
  text-align: left;
  font-size: 0.9rem;
}

.params-table th {
  color: var(--color-text-dim);
  font-weight: 500;
}

.params-table td {
  text-align: right;
  color: var(--color-text-muted);
}

.params-note {
  margin-top: 16px;
  padding: 12px;
  background: var(--color-surface-2);
  border-radius: var(--radius);
  font-size: 0.85rem;
  color: var(--color-text-dim);
}

/* ============================================
   CUTTING SAMPLES / GALLERY
   ============================================ */
.samples-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.sample-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all var(--transition);
  box-shadow: var(--shadow);
}

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

.sample-video {
  width: 100%;
  aspect-ratio: 16/9;
  background: var(--color-surface-2);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.video-embed {
  width: 100%;
  aspect-ratio: 16/9;
  overflow: hidden;
}

.video-embed iframe {
  width: 100%;
  height: 100%;
}

.sample-video img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.sample-play {
  position: absolute;
  width: 56px;
  height: 56px;
  background: rgba(37, 99, 235, 0.9);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.25rem;
  cursor: pointer;
  transition: all var(--transition);
}

.sample-play:hover {
  transform: scale(1.1);
  background: var(--color-primary);
}

.sample-info {
  padding: 20px;
}

.sample-info h4 {
  font-size: 1rem;
  margin-bottom: 4px;
  color: var(--color-text);
}

.sample-info p {
  font-size: 0.85rem;
  color: var(--color-text-dim);
}

.sample-tag {
  display: inline-block;
  background: rgba(37, 99, 235, 0.1);
  color: var(--color-primary);
  padding: 4px 10px;
  border-radius: 50px;
  font-size: 0.75rem;
  font-weight: 600;
  margin-top: 8px;
}

/* ============================================
   REFERENCE / CUSTOMERS
   ============================================ */
.reference-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.reference-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow);
}

.reference-card h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.reference-card .location {
  color: var(--color-text-dim);
  font-size: 0.9rem;
  margin-bottom: 16px;
}

.reference-card p {
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

.reference-goal {
  margin-top: 48px;
  text-align: center;
  padding: 40px;
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.08), rgba(8, 145, 178, 0.08));
  border: 1px solid var(--color-primary-light);
  border-radius: var(--radius-lg);
}

.reference-goal h3 {
  font-size: 1.5rem;
  margin-bottom: 8px;
  color: var(--color-primary);
}

.reference-goal p {
  color: var(--color-text-muted);
}

/* ============================================
   CONTACT
   ============================================ */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 20px;
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  transition: all var(--transition);
  box-shadow: var(--shadow);
}

.contact-item:hover {
  border-color: var(--color-primary-light);
}

.contact-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius);
  background: rgba(37, 99, 235, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  font-size: 1.25rem;
  flex-shrink: 0;
}

.contact-item h4 {
  font-size: 0.9rem;
  margin-bottom: 4px;
}

.contact-item p {
  font-size: 1rem;
  color: var(--color-text);
}

.contact-item a {
  color: var(--color-primary-light);
}

.contact-form {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow-lg);
}

.contact-form h3 {
  margin-bottom: 24px;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 0.9rem;
  font-weight: 500;
  margin-bottom: 8px;
  color: var(--color-text-muted);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 14px 16px;
  background: var(--color-bg);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius);
  color: var(--color-text);
  font-size: 1rem;
  font-family: inherit;
  transition: all var(--transition);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group textarea {
  min-height: 120px;
  resize: vertical;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.form-submit {
  width: 100%;
  margin-top: 8px;
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
  background: var(--color-text);
  padding: 48px 0 24px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 40px;
}

.footer-brand .logo-brand {
  color: white;
}

.footer-brand .logo-tagline {
  color: rgba(255,255,255,0.5);
}

.footer-brand p {
  margin-top: 16px;
  font-size: 0.9rem;
  max-width: 300px;
  color: rgba(255,255,255,0.6);
}

.footer h4 {
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: rgba(255,255,255,0.5);
  margin-bottom: 16px;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-links a {
  color: rgba(255,255,255,0.7);
  font-size: 0.95rem;
}

.footer-links a:hover {
  color: white;
}

.footer-badge {
  display: inline-block;
  background: var(--color-primary);
  color: white;
  padding: 4px 12px;
  border-radius: 50px;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.5px;
}

.footer-auth {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  color: white;
  padding: 10px 16px;
  border-radius: 12px;
  margin-bottom: 12px;
  line-height: 1.5;
  display: inline-block;
}

.footer-auth-line {
  font-weight: 700;
  font-size: 0.85rem;
  letter-spacing: 0.3px;
}

.footer-auth-line + .footer-auth-line {
  margin-top: 2px;
}

.footer-auth-line a {
  color: rgba(255,255,255,0.85);
  font-weight: 400;
  font-size: 0.9rem;
}

.footer-auth-line a:hover {
  color: white;
}

.footer-link a {
  color: rgba(255,255,255,0.6);
  font-size: 0.9rem;
}

.footer-link a:hover {
  color: white;
}

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid rgba(255,255,255,0.1);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  color: rgba(255,255,255,0.4);
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-subtitle {
    margin: 0 auto 32px;
  }

  .hero-stats {
    justify-content: center;
  }

  .hero-actions {
    justify-content: center;
  }

  .hero-visual {
    order: -1;
  }

  .hero-image {
    max-width: 400px;
  }

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

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

@media (max-width: 768px) {
  .nav {
    display: none;
  }

  .mobile-toggle {
    display: block;
  }

  .nav.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: white;
    border-bottom: 1px solid var(--color-border);
    padding: 16px;
    box-shadow: var(--shadow);
  }

  .hero-stats {
    flex-direction: column;
    gap: 16px;
  }

  .hero-stat {
    text-align: center;
  }

  .section {
    padding: 64px 0;
  }

  .advantage-grid {
    grid-template-columns: 1fr;
  }

  .comparison-section {
    padding: 24px;
  }

  .samples-grid {
    grid-template-columns: 1fr;
  }

  .reference-grid {
    grid-template-columns: 1fr;
  }

  .contact-grid {
    grid-template-columns: 1fr;
  }

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

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }

  .principle-grid {
    grid-template-columns: 1fr;
  }
}

/* ============================================
   ANIMATIONS
   ============================================ */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: all 0.6s ease;
}

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

/* ============================================
   MISC
   ============================================ */
.section-alt .feature-card,
.section-alt .advantage-card,
.section-alt .reference-card,
.section-alt .params-card {
  background: white;
}

.section:not(.section-alt) .feature-card,
.section:not(.section-alt) .advantage-card,
.section:not(.section-alt) .reference-card,
.section:not(.section-alt) .params-card {
  background: white;
}

.header-inner .logo img {
  height: 44px;
}