/* ===== CSS Variables ===== */
:root {
  --color-bg: #f0f6fc;
  --color-bg-gradient-start: #eef5fc;
  --color-bg-gradient-end: #e3eef9;
  --color-surface: #ffffff;
  --color-surface-hover: #f8fbff;
  --color-primary: #5b8def;
  --color-primary-light: #7eb3ff;
  --color-primary-lighter: #a8cfff;
  --color-primary-dark: #3b6fd6;
  --color-primary-darker: #2c5cb8;
  --color-text: #1e3a5f;
  --color-text-secondary: #5a7596;
  --color-text-light: #8aa4c0;
  --color-border: #dbe7f3;
  --color-border-light: #ecf3fa;
  --color-accent: #e8f2ff;
  --color-success: #4caf7d;
  --shadow-sm: 0 2px 8px rgba(91, 141, 239, 0.06);
  --shadow-md: 0 4px 20px rgba(91, 141, 239, 0.10);
  --shadow-lg: 0 8px 40px rgba(91, 141, 239, 0.14);
  --radius-sm: 8px;
  --radius: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --transition: all 0.3s ease;
  --max-width: 1200px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: 'Segoe UI', 'PingFang SC', 'Hiragino Sans', 'Noto Sans JP', 'Noto Sans SC', 'Helvetica Neue', Arial, sans-serif;
  background: linear-gradient(180deg, var(--color-bg-gradient-start) 0%, var(--color-bg-gradient-end) 100%);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

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

/* ===== Navbar ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border-light);
  transition: var(--transition);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 2rem;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--color-primary);
  flex-shrink: 0;
}

.logo svg {
  width: 32px;
  height: 32px;
}

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

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  margin-left: auto;
}

.nav-links a {
  display: block;
  padding: 0.5rem 1rem;
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
}

.nav-links a:hover {
  color: var(--color-primary);
  background: var(--color-accent);
}

.nav-links a.active {
  color: var(--color-primary);
  background: var(--color-accent);
}

/* ===== Language Switcher ===== */
.lang-switcher {
  position: relative;
  margin-left: 0.5rem;
}

.lang-btn {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 0.875rem;
  background: var(--color-accent);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  list-style: none;
  transition: var(--transition);
}

.lang-btn::-webkit-details-marker {
  display: none;
}

.lang-btn:hover {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.lang-btn svg {
  width: 16px;
  height: 16px;
}

.lang-dropdown {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  min-width: 160px;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
  padding: 0.375rem;
  z-index: 1001;
}

.lang-dropdown a {
  display: block;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  color: var(--color-text);
  font-size: 0.875rem;
  transition: var(--transition);
}

.lang-dropdown a:hover {
  background: var(--color-accent);
  color: var(--color-primary);
}

.lang-dropdown a.active {
  background: var(--color-primary);
  color: #fff;
  font-weight: 600;
}

/* ===== Hamburger ===== */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  margin-left: 0.5rem;
}

.hamburger span {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: var(--transition);
}

.hamburger span:not(:last-child) {
  margin-bottom: 4px;
}

.hamburger.is-open span:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.hamburger.is-open span:nth-child(2) {
  opacity: 0;
}

.hamburger.is-open span:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

/* ===== Hero ===== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 6rem 2rem 4rem;
  position: relative;
  overflow: hidden;
}

.hero::before,
.hero::after {
  content: '';
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.4;
  z-index: 0;
}

.hero::before {
  width: 500px;
  height: 500px;
  background: var(--color-primary-lighter);
  top: -150px;
  right: -100px;
}

.hero::after {
  width: 400px;
  height: 400px;
  background: #c8e0f7;
  bottom: -100px;
  left: -80px;
}

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

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  color: var(--color-text);
  line-height: 1.2;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}

.hero h1 .gradient-text {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: clamp(1rem, 2.5vw, 1.25rem);
  color: var(--color-text-secondary);
  margin-bottom: 2rem;
}

.hero-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.875rem 2rem;
  background: var(--color-primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  box-shadow: 0 4px 16px rgba(91, 141, 239, 0.3);
}

.hero-cta:hover {
  background: var(--color-primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(91, 141, 239, 0.4);
}

.hero-cta svg {
  width: 20px;
  height: 20px;
}

/* ===== Section Common ===== */
.section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 5rem 2rem;
}

.section-title {
  text-align: center;
  margin-bottom: 3rem;
}

.section-title h2 {
  font-size: clamp(1.5rem, 4vw, 2.25rem);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 0.5rem;
}

.section-title p {
  color: var(--color-text-secondary);
  font-size: 1.05rem;
}

/* ===== Products ===== */
.product-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

.product-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.product-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary-lighter);
}

.product-icon {
  width: 64px;
  height: 64px;
  border-radius: var(--radius);
  background: var(--color-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
}

.product-icon svg {
  width: 36px;
  height: 36px;
}

.product-card h3 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 0.25rem;
}

.product-tagline {
  color: var(--color-primary);
  font-size: 0.95rem;
  font-weight: 500;
  margin-bottom: 0.75rem;
}

.product-desc {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
  margin-bottom: 1.5rem;
}

.product-features {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.75rem;
}

.product-features li {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  padding: 0.375rem 0.75rem;
  background: var(--color-accent);
  border-radius: 100px;
  font-size: 0.8125rem;
  color: var(--color-primary-dark);
  font-weight: 500;
}

.product-features li::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-primary);
  flex-shrink: 0;
}

.btn-visit {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 600;
  margin-top: auto;
  transition: var(--transition);
}

.btn-visit:hover {
  background: var(--color-primary-dark);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(91, 141, 239, 0.3);
}

.btn-visit svg {
  width: 18px;
  height: 18px;
}

/* ===== Features ===== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}

.feature-card {
  text-align: center;
  padding: 2rem 1.5rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary-lighter);
}

.feature-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--color-accent), #d9e8fb);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1.25rem;
}

.feature-icon svg {
  width: 28px;
  height: 28px;
  color: var(--color-primary);
}

.feature-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.5rem;
}

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

/* ===== Footer ===== */
.footer {
  background: #fff;
  border-top: 1px solid var(--color-border-light);
  padding: 3rem 2rem 2rem;
  margin-top: 2rem;
}

.footer-content {
  max-width: var(--max-width);
  margin: 0 auto;
  text-align: center;
}

.footer-brand {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 1rem;
}

.footer-brand svg {
  width: 28px;
  height: 28px;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-bottom: 1.5rem;
}

.footer-links a {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
}

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

.footer-copyright {
  color: var(--color-text-light);
  font-size: 0.85rem;
}

/* ===== Scroll Reveal ===== */
.reveal-hidden {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ===== Responsive ===== */
@media (max-width: 968px) {
  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: 1rem;
    gap: 0.25rem;
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
  }

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

  .nav-links a {
    width: 100%;
    padding: 0.75rem 1rem;
  }

  .hamburger {
    display: flex;
  }

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

  .section {
    padding: 3.5rem 1.5rem;
  }

  .hero {
    min-height: 90vh;
    padding: 5rem 1.5rem 3rem;
  }

  .footer-links {
    flex-direction: column;
    gap: 0.75rem;
  }
}

@media (max-width: 480px) {
  .feature-grid {
    grid-template-columns: 1fr;
  }

  .product-card {
    padding: 1.75rem;
  }

  .nav-container {
    padding: 0 1rem;
  }
}