/* ================================
   gizin.ai — Global Styles
   ================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Noto+Sans+JP:wght@300;400;500;600;700&display=swap');

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

:root {
  --bg-primary: #0a0a0a;
  --bg-secondary: #111111;
  --bg-card: #1a1a1a;
  --text-primary: #f5f5f5;
  --text-secondary: #999999;
  --text-muted: #666666;
  --accent: #e0e0e0;
  --border: #222222;
  --font-en: 'Inter', sans-serif;
  --font-ja: 'Noto Sans JP', 'Inter', sans-serif;
}

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

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

body.lang-ja {
  font-family: var(--font-ja);
}

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

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

/* --- Layout --- */
.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 24px;
}

/* --- Header --- */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 20px 0;
  background-color: rgba(10, 10, 10, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header-logo {
  font-size: 1.125rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--text-primary);
}

.lang-switch {
  display: flex;
  gap: 4px;
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.05em;
}

.lang-switch a {
  padding: 6px 12px;
  border-radius: 4px;
  color: var(--text-muted);
  transition: color 0.2s, background-color 0.2s;
}

.lang-switch a:hover {
  color: var(--text-primary);
}

.lang-switch a.active {
  color: var(--text-primary);
  background-color: var(--bg-card);
}

/* --- Hero Section --- */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-top: 80px;
}

.hero-tagline {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 24px;
}

.hero-tagline .highlight {
  display: inline;
}

.hero-sub {
  font-size: clamp(1.125rem, 2.5vw, 1.5rem);
  font-weight: 300;
  color: var(--text-secondary);
  letter-spacing: 0.01em;
}

/* --- Explanation Section --- */
.explanation {
  padding: 120px 0;
}

.explanation-text {
  font-size: clamp(1.25rem, 2.5vw, 1.75rem);
  font-weight: 300;
  line-height: 2;
  color: var(--text-secondary);
  max-width: 680px;
}

.explanation-text strong {
  color: var(--text-primary);
  font-weight: 500;
}

.explanation-text .line {
  display: block;
  margin-bottom: 16px;
}

.explanation-closing {
  margin-top: 48px;
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--text-primary);
  font-weight: 400;
  line-height: 1.8;
}

/* --- Company Section --- */
.company {
  padding: 120px 0;
  border-top: 1px solid var(--border);
}

.company-label {
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 32px;
}

.company-stat {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 600;
  line-height: 1.3;
  margin-bottom: 24px;
}

.company-desc {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--text-secondary);
  font-weight: 300;
  line-height: 1.8;
  max-width: 600px;
}

/* --- Member Grid (placeholder) --- */
.members {
  padding: 80px 0;
}

.members-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(56px, 1fr));
  gap: 8px;
  opacity: 0.7;
}

.members-grid img {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
  border-radius: 8px;
  background-color: var(--bg-card);
}

/* --- Links Section --- */
.links {
  padding: 80px 0;
  border-top: 1px solid var(--border);
}

.links-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.link-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  font-size: 0.9375rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-primary);
  background-color: transparent;
  transition: background-color 0.2s, border-color 0.2s;
  cursor: pointer;
}

.link-btn:hover {
  background-color: var(--bg-card);
  border-color: #333;
}

.link-btn svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

/* --- Contact Section --- */
.contact {
  padding: 120px 0;
  border-top: 1px solid var(--border);
}

.contact-heading {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 600;
  margin-bottom: 12px;
}

.contact-sub {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 48px;
  font-weight: 300;
}

.contact-form {
  max-width: 520px;
}

.form-group {
  margin-bottom: 24px;
}

.form-group label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 14px 16px;
  font-size: 1rem;
  font-family: inherit;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-primary);
  outline: none;
  transition: border-color 0.2s;
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: #444;
}

.form-group textarea {
  min-height: 140px;
  resize: vertical;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: var(--text-muted);
}

.form-submit {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 36px;
  font-size: 1rem;
  font-weight: 500;
  font-family: inherit;
  background-color: var(--text-primary);
  color: var(--bg-primary);
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: opacity 0.2s;
}

.form-submit:hover {
  opacity: 0.85;
}

.form-submit:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.form-status {
  margin-top: 16px;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.form-status.success {
  color: #4ade80;
}

.form-status.error {
  color: #f87171;
}

/* --- Footer --- */
.footer {
  padding: 40px 0;
  border-top: 1px solid var(--border);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8125rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  gap: 24px;
}

.footer-links a {
  color: var(--text-muted);
  transition: color 0.2s;
}

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

/* --- Screen Reader Only --- */
.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;
}

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

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

/* --- Responsive --- */
@media (max-width: 768px) {
  .container {
    padding: 0 20px;
  }

  .hero {
    min-height: 85vh;
    padding-top: 72px;
  }

  .explanation {
    padding: 80px 0;
  }

  .company {
    padding: 80px 0;
  }

  .links {
    padding: 60px 0;
  }

  .links-grid {
    flex-direction: column;
  }

  .link-btn {
    justify-content: center;
  }

  .contact {
    padding: 80px 0;
  }

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

  .members-grid {
    grid-template-columns: repeat(auto-fill, minmax(48px, 1fr));
    gap: 6px;
  }
}

@media (max-width: 480px) {
  .hero-tagline {
    font-size: 2rem;
  }
}