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

:root {
  --color-bg: #fafafa;
  --color-bg-dark: #111111;
  --color-text: #1a1a1a;
  --color-text-secondary: #666666;
  --color-text-light: #f5f5f5;
  --color-text-light-secondary: #a0a0a0;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-border: #e5e5e5;
  --color-border-dark: #2a2a2a;
  --color-card: #ffffff;
  --color-card-hover: #f8f8f8;
  --font-sans: 'Inter', 'Noto Sans TC', -apple-system, BlinkMacSystemFont, sans-serif;
  --container-max: 1200px;
  --section-padding: 120px;
  --nav-height: 72px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

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

a {
  text-decoration: none;
  color: inherit;
}

img {
  max-width: 100%;
  display: block;
}

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

/* ========== Navigation ========== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: 1000;
  transition: var(--transition);
  background: transparent;
}

.nav.scrolled {
  background: rgba(250, 250, 250, 0.9);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border);
}

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

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--color-text);
}

.nav-logo-img {
  width: 32px;
  height: 32px;
  object-fit: contain;
}

.nav.at-top .nav-logo {
  color: var(--color-text-light);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 36px;
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: var(--transition);
  letter-spacing: 0.02em;
}

.nav.at-top .nav-links a {
  color: var(--color-text-light-secondary);
}

.nav-links a:hover {
  color: var(--color-text);
}

.nav.at-top .nav-links a:hover {
  color: var(--color-text-light);
}

.nav-cta {
  padding: 8px 20px !important;
  border: 1px solid var(--color-text);
  border-radius: 6px;
  transition: var(--transition) !important;
}

.nav.at-top .nav-cta {
  border-color: var(--color-text-light-secondary);
}

.nav-cta:hover {
  background: var(--color-text);
  color: var(--color-bg) !important;
}

.nav.at-top .nav-cta:hover {
  background: var(--color-text-light);
  color: var(--color-bg-dark) !important;
}

/* ========== Language Switch ========== */
.lang-switch {
  display: flex;
  align-items: center;
  gap: 4px;
  background: rgba(0, 0, 0, 0.06);
  border-radius: 6px;
  padding: 3px;
}

.nav.at-top .lang-switch {
  background: rgba(255, 255, 255, 0.1);
}

.lang-btn {
  padding: 4px 10px;
  font-size: 0.75rem;
  font-weight: 500;
  font-family: var(--font-sans);
  border: none;
  border-radius: 4px;
  cursor: pointer;
  background: transparent;
  color: var(--color-text-secondary);
  transition: var(--transition);
}

.nav.at-top .lang-btn {
  color: var(--color-text-light-secondary);
}

.lang-btn.active {
  background: var(--color-accent);
  color: #ffffff;
}

.lang-switch-mobile {
  display: none;
}

.nav-right-mobile {
  display: none;
  align-items: center;
  gap: 12px;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  transition: var(--transition);
}

.nav.at-top .nav-toggle span {
  background: var(--color-text-light);
}

/* ========== Hero ========== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, #0f0f0f 0%, #1a1a2e 50%, #16213e 100%);
  z-index: 0;
}

.hero-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 20% 50%, rgba(37, 99, 235, 0.08) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 20%, rgba(99, 102, 241, 0.06) 0%, transparent 50%);
}

.hero-content {
  position: relative;
  z-index: 1;
  padding-top: var(--nav-height);
}

.hero-label {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 24px;
}

.hero-title {
  font-size: clamp(2.5rem, 6vw, 5rem);
  font-weight: 700;
  line-height: 1.1;
  color: var(--color-text-light);
  margin-bottom: 28px;
  letter-spacing: -0.02em;
}

.hero-highlight {
  background: linear-gradient(135deg, #60a5fa, #a78bfa);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: 1.125rem;
  color: var(--color-text-light-secondary);
  max-width: 520px;
  line-height: 1.7;
  margin-bottom: 40px;
}

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

.hero-scroll {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  z-index: 1;
}

.hero-scroll span {
  font-size: 0.7rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-text-light-secondary);
}

.hero-scroll-line {
  width: 1px;
  height: 40px;
  background: linear-gradient(to bottom, var(--color-text-light-secondary), transparent);
  animation: scrollPulse 2s ease-in-out infinite;
}

@keyframes scrollPulse {
  0%, 100% { opacity: 0.3; }
  50% { opacity: 1; }
}

/* ========== Buttons ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 32px;
  font-size: 0.9rem;
  font-weight: 500;
  font-family: var(--font-sans);
  border-radius: 8px;
  transition: var(--transition);
  cursor: pointer;
  border: none;
  letter-spacing: 0.02em;
}

.btn-primary {
  background: var(--color-accent);
  color: #ffffff;
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.3);
}

.btn-ghost {
  background: transparent;
  color: var(--color-text-light-secondary);
  border: 1px solid var(--color-border-dark);
}

.btn-ghost:hover {
  color: var(--color-text-light);
  border-color: var(--color-text-light-secondary);
}

.btn-full {
  width: 100%;
}

/* ========== Sections ========== */
.section {
  padding: var(--section-padding) 0;
}

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

.section-header {
  text-align: center;
  max-width: 600px;
  margin: 0 auto 64px;
}

.section-label {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(1.75rem, 3.5vw, 2.75rem);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 1rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.section-dark .section-desc {
  color: var(--color-text-light-secondary);
}

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

.service-card {
  padding: 40px 32px;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  transition: var(--transition);
  background: var(--color-card);
}

.service-card:hover {
  border-color: var(--color-accent);
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.06);
}

.service-icon {
  width: 56px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #f0f4ff;
  border-radius: 12px;
  margin-bottom: 20px;
  color: var(--color-accent);
}

.service-card h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 10px;
}

.service-card p {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

/* ========== About ========== */
.about-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: start;
}

.about-left .section-label {
  text-align: left;
}

.about-left .section-title {
  text-align: left;
}

.about-right p {
  font-size: 1rem;
  color: var(--color-text-light-secondary);
  line-height: 1.8;
  margin-bottom: 20px;
}

.about-stats {
  display: flex;
  gap: 48px;
  margin-top: 40px;
  padding-top: 40px;
  border-top: 1px solid var(--color-border-dark);
}

.stat-number {
  display: block;
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-text-light);
  margin-bottom: 4px;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--color-text-light-secondary);
  letter-spacing: 0.05em;
}

/* ========== Carousel ========== */
.carousel {
  position: relative;
  max-width: 960px;
  margin: 0 auto;
  border-radius: 16px;
  overflow: hidden;
  background: #000;
}

.carousel-track {
  position: relative;
  aspect-ratio: 16 / 9;
}

.carousel-slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity 0.6s ease;
}

.carousel-slide.active {
  opacity: 1;
}

.carousel-slide img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.carousel-caption {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 24px 32px;
  background: linear-gradient(to top, rgba(0,0,0,0.6), transparent);
  color: #fff;
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: 0.02em;
}

.carousel-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: none;
  background: rgba(255,255,255,0.15);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  color: #fff;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  z-index: 2;
}

.carousel-btn:hover {
  background: rgba(255,255,255,0.3);
}

.carousel-btn-prev { left: 16px; }
.carousel-btn-next { right: 16px; }

.carousel-dots {
  position: absolute;
  bottom: 16px;
  right: 32px;
  display: flex;
  gap: 8px;
  z-index: 2;
}

.carousel-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  border: none;
  background: rgba(255,255,255,0.4);
  cursor: pointer;
  padding: 0;
  transition: var(--transition);
}

.carousel-dot.active {
  background: #fff;
  width: 24px;
  border-radius: 4px;
}

/* ========== Process ========== */
.process-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
}

.process-step {
  text-align: center;
  padding: 32px 20px;
}

.process-number {
  font-size: 3rem;
  font-weight: 700;
  color: #e8e8e8;
  margin-bottom: 16px;
  line-height: 1;
}

.process-step h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.process-step p {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

/* ========== Tech Grid ========== */
.tech-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 16px;
}

.tech-item {
  padding: 12px 28px;
  border: 1px solid var(--color-border-dark);
  border-radius: 100px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-light-secondary);
  transition: var(--transition);
}

.tech-item:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* ========== Contact ========== */
.contact-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: start;
}

.contact-left .section-label {
  text-align: left;
}

.contact-left .section-title {
  text-align: left;
}

.contact-desc {
  font-size: 1rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-top: 16px;
  margin-bottom: 32px;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.95rem;
  color: var(--color-text-secondary);
}

.contact-item svg {
  color: var(--color-accent);
  flex-shrink: 0;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 14px 18px;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 0.9rem;
  font-family: var(--font-sans);
  background: var(--color-card);
  color: var(--color-text);
  transition: var(--transition);
  outline: none;
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

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

/* ========== Footer ========== */
.footer {
  background: var(--color-bg-dark);
  padding: 60px 0 32px;
  border-top: 1px solid var(--color-border-dark);
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--color-border-dark);
}

.footer .nav-logo {
  color: var(--color-text-light);
}

.footer-brand p {
  font-size: 0.875rem;
  color: var(--color-text-light-secondary);
  margin-top: 8px;
}

.footer-links {
  display: flex;
  gap: 32px;
}

.footer-links a {
  font-size: 0.875rem;
  color: var(--color-text-light-secondary);
  transition: var(--transition);
}

.footer-links a:hover {
  color: var(--color-text-light);
}

.footer-bottom {
  padding-top: 24px;
  text-align: center;
}

.footer-bottom p {
  font-size: 0.8rem;
  color: var(--color-text-light-secondary);
}

/* ========== Screen Reader Only (SEO) ========== */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ========== Scroll Animations ========== */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ========== Responsive ========== */
@media (max-width: 1024px) {
  :root {
    --section-padding: 80px;
  }

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

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

  .about-layout,
  .contact-layout {
    grid-template-columns: 1fr;
    gap: 48px;
  }

}

@media (max-width: 768px) {
  :root {
    --section-padding: 64px;
    --nav-height: 64px;
  }

  .nav-links {
    display: none;
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(250, 250, 250, 0.98);
    backdrop-filter: blur(20px);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 32px;
  }

  .nav.at-top .nav-links {
    background: rgba(17, 17, 17, 0.98);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    font-size: 1.25rem;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-right-mobile {
    display: flex;
  }

  .nav-links .lang-switch {
    display: none;
  }

  .lang-switch-mobile {
    display: flex;
  }

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

  .process-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .about-stats {
    flex-direction: column;
    gap: 24px;
  }

  .hero-title {
    font-size: 2.25rem;
  }

  .hero-scroll {
    display: none;
  }
}