/**
 * Drift 静的サイト共通スタイル
 *
 * 概要:
 *   GitHub Pages用の静的ランディングページ・各種ページの共通CSS
 *   既存のNext.jsフロントエンドのダークテーマデザインを再現
 *
 * 主な仕様:
 *   - モバイルファーストのレスポンシブデザイン
 *   - ダークテーマ（slate系カラー）
 *   - グラデーション背景、グラスモーフィズム風装飾
 *
 * 制限事項:
 *   - フレームワーク不使用の純粋CSS
 */

/* ===== リセットとベース ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto,
    'Helvetica Neue', Arial, sans-serif;
  color: #e2e8f0;
  background: linear-gradient(180deg, #0f172a 0%, #1e293b 50%, #0f172a 100%);
  min-height: 100vh;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

ul {
  list-style: none;
}

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

/* ===== ユーティリティ ===== */
.container {
  max-width: 1152px;
  margin: 0 auto;
  padding: 0 24px;
}

.container--narrow {
  max-width: 768px;
  margin: 0 auto;
  padding: 0 24px;
}

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

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* ===== ヘッダー ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  transition: background-color 0.3s, box-shadow 0.3s;
  background: transparent;
}

.header--scrolled {
  background: rgba(15, 23, 42, 0.95);
  backdrop-filter: blur(12px);
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

.header__inner {
  max-width: 1152px;
  margin: 0 auto;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  justify-content: between;
}

.header__logo {
  display: flex;
  align-items: center;
  gap: 8px;
}

.header__logo-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, #3b82f6, #9333ea);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 18px;
}

.header__logo-text {
  font-size: 20px;
  font-weight: 700;
  color: #fff;
}

.header__nav {
  display: flex;
  align-items: center;
  gap: 24px;
}

.header__nav a {
  font-size: 14px;
  color: #94a3b8;
  transition: color 0.2s;
}

.header__nav a:hover {
  color: #fff;
}

/* ===== ヒーローセクション ===== */
.hero {
  position: relative;
  padding: 120px 24px 64px;
  overflow: hidden;
  text-align: center;
}

.hero__bg-circle-1 {
  position: absolute;
  top: 80px;
  left: 40px;
  width: 288px;
  height: 288px;
  background: rgba(59, 130, 246, 0.2);
  border-radius: 50%;
  filter: blur(48px);
  pointer-events: none;
}

.hero__bg-circle-2 {
  position: absolute;
  bottom: 80px;
  right: 40px;
  width: 384px;
  height: 384px;
  background: rgba(147, 51, 234, 0.2);
  border-radius: 50%;
  filter: blur(48px);
  pointer-events: none;
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  background: rgba(30, 41, 59, 0.5);
  backdrop-filter: blur(4px);
  border: 1px solid #334155;
  border-radius: 9999px;
  margin-bottom: 24px;
}

.hero__badge-dot {
  width: 8px;
  height: 8px;
  background: #4ade80;
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

.hero__badge-text {
  font-size: 12px;
  color: #cbd5e1;
}

.hero__title {
  font-size: 36px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 16px;
  line-height: 1.2;
}

.hero__title-gradient {
  background: linear-gradient(90deg, #60a5fa, #c084fc, #f472b6);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero__subtitle {
  font-size: 18px;
  color: #cbd5e1;
  margin-bottom: 12px;
}

.hero__description {
  font-size: 16px;
  color: #94a3b8;
  margin-bottom: 40px;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

.hero__cta {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  margin-bottom: 48px;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  background: linear-gradient(135deg, #3b82f6, #9333ea);
  color: #fff;
  border-radius: 12px;
  font-weight: 700;
  font-size: 16px;
  border: none;
  cursor: pointer;
  box-shadow: 0 10px 20px rgba(59, 130, 246, 0.4);
  transition: transform 0.2s, box-shadow 0.2s;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 28px rgba(59, 130, 246, 0.5);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  background: #1e293b;
  color: #fff;
  border-radius: 12px;
  font-weight: 700;
  font-size: 16px;
  border: 1px solid #334155;
  cursor: pointer;
  transition: background 0.2s;
}

.btn-secondary:hover {
  background: #334155;
}

/* ===== 特徴セクション ===== */
.features {
  padding: 64px 24px;
  background: rgba(30, 41, 59, 0.3);
}

.section-title {
  font-size: 28px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 12px;
}

.section-subtitle {
  font-size: 18px;
  color: #94a3b8;
  margin-bottom: 48px;
}

.features__grid {
  display: grid;
  gap: 24px;
}

.feature-card {
  background: rgba(30, 41, 59, 0.5);
  backdrop-filter: blur(4px);
  border: 1px solid #334155;
  border-radius: 16px;
  padding: 24px;
  transition: border-color 0.3s;
}

.feature-card:hover {
  border-color: rgba(59, 130, 246, 0.5);
}

.feature-card__icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  font-size: 24px;
  color: #fff;
}

.feature-card__icon--blue {
  background: linear-gradient(135deg, #3b82f6, #2563eb);
}

.feature-card__icon--purple {
  background: linear-gradient(135deg, #a855f7, #9333ea);
}

.feature-card__icon--pink {
  background: linear-gradient(135deg, #ec4899, #db2777);
}

.feature-card__title {
  font-size: 20px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 12px;
}

.feature-card__description {
  font-size: 14px;
  color: #94a3b8;
  line-height: 1.7;
}

/* ===== ステップセクション ===== */
.steps {
  padding: 64px 24px;
}

.step {
  display: flex;
  gap: 20px;
  align-items: flex-start;
  margin-bottom: 24px;
}

.step__icon {
  flex-shrink: 0;
  width: 56px;
  height: 56px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  color: #fff;
}

.step__icon--blue { background: linear-gradient(135deg, #3b82f6, #2563eb); }
.step__icon--purple { background: linear-gradient(135deg, #a855f7, #9333ea); }
.step__icon--pink { background: linear-gradient(135deg, #ec4899, #db2777); }
.step__icon--green { background: linear-gradient(135deg, #22c55e, #16a34a); }
.step__icon--amber { background: linear-gradient(135deg, #f59e0b, #d97706); }

.step__number {
  font-size: 32px;
  font-weight: 700;
  color: #334155;
  margin-right: 12px;
}

.step__title {
  font-size: 20px;
  font-weight: 700;
  color: #fff;
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
}

.step__description {
  font-size: 16px;
  color: #94a3b8;
  line-height: 1.6;
}

/* ===== おすすめセクション ===== */
.recommend {
  padding: 64px 24px;
  background: rgba(30, 41, 59, 0.3);
}

.recommend__grid {
  display: grid;
  gap: 20px;
}

.recommend__item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  background: rgba(30, 41, 59, 0.5);
  backdrop-filter: blur(4px);
  border: 1px solid #334155;
  border-radius: 12px;
  padding: 20px;
}

.recommend__check {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  background: #22c55e;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 4px;
  color: #fff;
  font-size: 12px;
}

.recommend__text {
  font-size: 16px;
  color: #cbd5e1;
}

/* ===== CTA（最終コール）セクション ===== */
.cta {
  padding: 64px 24px;
}

.cta__box {
  background: linear-gradient(135deg, #2563eb, #7c3aed);
  border-radius: 24px;
  padding: 48px 40px;
  text-align: center;
  box-shadow: 0 25px 50px rgba(30, 64, 175, 0.4);
}

.cta__title {
  font-size: 28px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 20px;
}

.cta__subtitle {
  font-size: 18px;
  color: #bfdbfe;
  margin-bottom: 24px;
}

.cta__btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 16px 32px;
  background: #fff;
  color: #2563eb;
  border-radius: 12px;
  font-weight: 700;
  font-size: 18px;
  border: none;
  cursor: pointer;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
  transition: transform 0.2s, box-shadow 0.2s;
}

.cta__btn:hover {
  transform: scale(1.05);
  box-shadow: 0 14px 28px rgba(0, 0, 0, 0.3);
}

.cta__note {
  font-size: 12px;
  color: #93c5fd;
  margin-top: 20px;
}

/* ===== フッター ===== */
.footer {
  padding: 32px 24px;
  border-top: 1px solid #1e293b;
}

.footer__inner {
  max-width: 1152px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

.footer__logo {
  display: flex;
  align-items: center;
  gap: 8px;
}

.footer__logo-icon {
  width: 24px;
  height: 24px;
  background: linear-gradient(135deg, #3b82f6, #9333ea);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 14px;
}

.footer__logo-text {
  font-size: 18px;
  font-weight: 700;
  color: #fff;
}

.footer__links {
  display: flex;
  gap: 24px;
}

.footer__links a {
  font-size: 14px;
  color: #94a3b8;
  transition: color 0.2s;
}

.footer__links a:hover {
  color: #fff;
}

.footer__copyright {
  font-size: 12px;
  color: #64748b;
  margin-top: 4px;
}

/* ===== 法的ページ共通 ===== */
.legal-page {
  min-height: 100vh;
}

.legal-header {
  background: #1e293b;
  border-bottom: 1px solid #334155;
  padding: 16px 24px;
}

.legal-header__inner {
  max-width: 768px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.legal-header__back {
  display: flex;
  align-items: center;
  gap: 8px;
  color: #fff;
  font-size: 14px;
  transition: color 0.2s;
}

.legal-header__back:hover {
  color: #93c5fd;
}

.legal-header__title {
  font-size: 20px;
  font-weight: 600;
  color: #fff;
}

.legal-content {
  max-width: 768px;
  margin: 0 auto;
  padding: 32px 24px;
}

.legal-content__date {
  text-align: right;
  font-size: 14px;
  color: #94a3b8;
  margin-bottom: 32px;
}

.legal-content section {
  margin-bottom: 40px;
}

.legal-content h2 {
  font-size: 18px;
  font-weight: 600;
  color: #fff;
  margin-bottom: 16px;
}

.legal-content h3 {
  font-size: 16px;
  font-weight: 500;
  color: #e2e8f0;
  margin-bottom: 8px;
}

.legal-content p {
  color: #cbd5e1;
  line-height: 1.7;
  margin-bottom: 12px;
}

.legal-content ul {
  list-style: disc;
  padding-left: 24px;
  margin-bottom: 16px;
}

.legal-content li {
  color: #cbd5e1;
  margin-bottom: 4px;
}

.legal-content .contact-info {
  color: #93c5fd;
}

/* ===== お問い合わせページ ===== */
.contact-page {
  min-height: 100vh;
  padding-top: 60px;
}

.contact-form {
  max-width: 640px;
  margin: 0 auto;
  padding: 32px 24px;
}

.contact-form__title {
  font-size: 28px;
  font-weight: 700;
  color: #fff;
  text-align: center;
  margin-bottom: 8px;
}

.contact-form__subtitle {
  font-size: 16px;
  color: #94a3b8;
  text-align: center;
  margin-bottom: 32px;
}

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

.form-group label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: #e2e8f0;
  margin-bottom: 8px;
}

.form-group label .required {
  color: #ef4444;
  margin-left: 4px;
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: 12px 16px;
  background: #1e293b;
  border: 1px solid #334155;
  border-radius: 8px;
  color: #e2e8f0;
  font-size: 16px;
  font-family: inherit;
  transition: border-color 0.2s;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  outline: none;
  border-color: #3b82f6;
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

.form-input::placeholder,
.form-textarea::placeholder {
  color: #64748b;
}

.form-textarea {
  min-height: 160px;
  resize: vertical;
}

.form-select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%2394a3b8' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 16px center;
  padding-right: 40px;
}

.form-submit {
  width: 100%;
  padding: 14px 24px;
  background: linear-gradient(135deg, #3b82f6, #9333ea);
  color: #fff;
  border: none;
  border-radius: 12px;
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.2s;
}

.form-submit:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}

.form-submit:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

.form-message {
  text-align: center;
  padding: 16px;
  border-radius: 8px;
  margin-bottom: 24px;
  font-size: 14px;
}

.form-message--success {
  background: rgba(34, 197, 94, 0.1);
  border: 1px solid rgba(34, 197, 94, 0.3);
  color: #4ade80;
}

.form-message--error {
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid rgba(239, 68, 68, 0.3);
  color: #f87171;
}

/* ===== App Storeバッジ ===== */
.app-store-badge {
  display: inline-block;
  transition: opacity 0.2s;
}

.app-store-badge:hover {
  opacity: 0.8;
}

.app-store-badge img {
  height: 48px;
}

/* ===== レスポンシブ ===== */
@media (min-width: 640px) {
  .hero__cta {
    flex-direction: row;
    justify-content: center;
  }

  .hero__title {
    font-size: 48px;
  }
}

@media (min-width: 768px) {
  .features__grid {
    grid-template-columns: repeat(3, 1fr);
  }

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

  .footer__inner {
    flex-direction: row;
    justify-content: space-between;
  }

  .hero__title {
    font-size: 56px;
  }

  .section-title {
    font-size: 36px;
  }

  .cta__title {
    font-size: 36px;
  }
}