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

/* デザインシステムトークン */
:root {
  --color-primary: #04384c; /* コーポレートネイビー */
  --color-primary-light: #065370;
  --color-primary-dark: #02202c;
  --color-accent: #f7da38; /* アクセントイエロー */
  --color-text-main: #ffffff;
  --color-text-muted: rgba(255, 255, 255, 0.7);
  --color-bg-overlay: rgba(2, 15, 22, 0.65);
  
  --font-en: 'Outfit', 'Inter', sans-serif;
  --font-ja: 'Noto Sans JP', sans-serif;
  
  --transition-smooth: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  --glass-bg: rgba(255, 255, 255, 0.06);
  --glass-border: rgba(255, 255, 255, 0.08);
  --glass-shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-ja);
  background-color: var(--color-primary-dark);
  color: var(--color-text-main);
  min-height: 100vh;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
}

/* 背景グラフィック */
.bg-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  overflow: hidden;
}

.bg-image {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transform: scale(1.05);
  filter: brightness(0.85);
  animation: bgZoom 20s infinite alternate ease-in-out;
}

.bg-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    135deg,
    rgba(4, 56, 76, 0.85) 0%,
    rgba(2, 20, 28, 0.95) 100%
  );
  backdrop-filter: blur(2px);
}

/* なめらかなオーロラ風グラデーションサークル（マイクロアニメーション） */
.gradient-sphere {
  position: absolute;
  width: 600px;
  height: 600px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(6, 83, 112, 0.3) 0%, rgba(4, 56, 76, 0) 70%);
  top: -200px;
  right: -100px;
  animation: floatSphere 12s infinite alternate ease-in-out;
  pointer-events: none;
}

.gradient-sphere-2 {
  position: absolute;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(135, 231, 255, 0.15) 0%, rgba(4, 56, 76, 0) 70%);
  bottom: -150px;
  left: -100px;
  animation: floatSphere2 15s infinite alternate ease-in-out;
  pointer-events: none;
}

/* メインコンテンツエリア */
header {
  padding: 40px 20px;
  text-align: center;
  z-index: 10;
}

.logo-container {
  display: inline-block;
  opacity: 0;
  transform: translateY(-20px);
  animation: fadeInDown 1s forwards ease-out;
}

.logo-subtitle {
  font-family: var(--font-en);
  font-size: 0.9rem;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 8px;
  font-weight: 600;
}

.logo-title {
  font-size: 1.8rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  background: linear-gradient(135deg, #ffffff 0%, #d8ffff 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

main {
  flex-grow: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  z-index: 10;
}

.gateway-container {
  max-width: 1100px;
  width: 100%;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  opacity: 0;
  transform: scale(0.98);
  animation: fadeInScale 1.2s 0.3s forwards cubic-bezier(0.16, 1, 0.3, 1);
}

/* 言語選択カード */
.lang-card {
  position: relative;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: 24px;
  padding: 60px 40px;
  text-decoration: none;
  color: var(--color-text-main);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  text-align: center;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: var(--glass-shadow);
  transition: var(--transition-smooth);
  overflow: hidden;
  min-height: 420px;
}

.lang-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.05) 0%,
    rgba(255, 255, 255, 0) 100%
  );
  opacity: 1;
  transition: var(--transition-smooth);
}

.lang-card::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--color-accent) 0%, #87e7ff 100%);
  transform: scaleX(0);
  transform-origin: left;
  transition: var(--transition-smooth);
}

/* ホバーエフェクト */
.lang-card:hover {
  transform: translateY(-8px);
  border-color: rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.09);
  box-shadow: 0 30px 60px rgba(0, 0, 0, 0.4), 
              0 0 40px rgba(135, 231, 255, 0.1);
}

.lang-card:hover::after {
  transform: scaleX(1);
}

.lang-badge {
  font-family: var(--font-en);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-accent);
  border: 1px solid rgba(247, 218, 56, 0.4);
  padding: 6px 16px;
  border-radius: 50px;
  margin-bottom: 24px;
  background: rgba(247, 218, 56, 0.05);
  transition: var(--transition-smooth);
}

.lang-card:hover .lang-badge {
  background: var(--color-accent);
  color: var(--color-primary-dark);
  border-color: var(--color-accent);
  box-shadow: 0 0 15px rgba(247, 218, 56, 0.3);
}

.card-title {
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 12px;
  letter-spacing: 0.02em;
}

.office-name {
  font-size: 1.1rem;
  font-weight: 500;
  margin-bottom: 24px;
  color: var(--color-text-main);
  opacity: 0.9;
}

.card-desc {
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--color-text-muted);
  max-width: 320px;
  margin-bottom: 40px;
  flex-grow: 1;
}

.action-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-ja);
  font-weight: 600;
  font-size: 1rem;
  color: var(--color-text-main);
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.15);
  padding: 14px 36px;
  border-radius: 50px;
  transition: var(--transition-smooth);
  width: 100%;
  max-width: 260px;
}

.action-btn i {
  margin-left: 8px;
  font-size: 0.9rem;
  transition: var(--transition-smooth);
}

.lang-card:hover .action-btn {
  background: var(--color-text-main);
  color: var(--color-primary-dark);
  border-color: var(--color-text-main);
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.15);
}

.lang-card:hover .action-btn i {
  transform: translateX(4px);
}

/* フッター */
footer {
  text-align: center;
  padding: 40px 20px;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  z-index: 10;
  opacity: 0;
  animation: fadeIn 1.5s 0.6s forwards ease-out;
}

.footer-info {
  margin-bottom: 12px;
  line-height: 1.6;
}

.footer-info span {
  margin: 0 10px;
}

.copyright {
  font-family: var(--font-en);
  letter-spacing: 0.05em;
}

/* アニメーションキーフレーム */
@keyframes bgZoom {
  0% { transform: scale(1.02); }
  100% { transform: scale(1.08); }
}

@keyframes floatSphere {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(-30px, 50px) scale(1.05); }
}

@keyframes floatSphere2 {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(40px, -40px) scale(1.1); }
}

@keyframes fadeInDown {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInScale {
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes fadeIn {
  to {
    opacity: 1;
  }
}

/* メディアクエリ（レスポンシブデザイン） */
@media (max-width: 820px) {
  .gateway-container {
    grid-template-columns: 1fr;
    gap: 24px;
    max-width: 500px;
  }
  
  .lang-card {
    min-height: auto;
    padding: 40px 30px;
  }
  
  .card-title {
    font-size: 1.8rem;
  }
  
  .card-desc {
    margin-bottom: 30px;
  }
  
  .logo-title {
    font-size: 1.5rem;
  }
  
  header {
    padding: 30px 20px;
  }
  
  footer {
    padding: 30px 20px;
  }
}

@media (max-width: 480px) {
  .logo-title {
    font-size: 1.25rem;
  }
  
  .logo-subtitle {
    font-size: 0.75rem;
  }
  
  .card-title {
    font-size: 1.6rem;
  }
  
  .office-name {
    font-size: 0.95rem;
  }
  
  .footer-info span {
    display: block;
    margin: 4px 0;
  }
}