:root {
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --secondary: #0ea5e9;
  --secondary-hover: #0284c7;
  --danger: #ef4444;
  --danger-hover: #dc2626;
  --bg: #f8fafc;
  --card-bg: #ffffff;
  --text-main: #1e293b;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --radius: 12px;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif;
  background-color: var(--bg);
  color: var(--text-main);
  line-height: 1.6;
}

.hidden {
  display: none !important;
}

/* ヘッダー */
.app-header {
  background-color: var(--card-bg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 0.85rem 1.25rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.app-title {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--primary);
  cursor: pointer;
}

.auth-status-area {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.badge {
  font-size: 0.75rem;
  background-color: #eef2ff;
  color: var(--primary);
  padding: 0.25rem 0.6rem;
  border-radius: 999px;
  font-weight: 600;
}

/* メインコンテナ */
.container {
  max-width: 900px;
  margin: 1.5rem auto;
  padding: 0 1.25rem 3rem;
}

/* ボタン */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.65rem 1.25rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: 8px;
  border: none;
  cursor: pointer;
  transition: background-color 0.2s, transform 0.1s;
}

.btn:active {
  transform: scale(0.98);
}

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

.btn-secondary {
  background-color: var(--secondary);
  color: #fff;
}
.btn-secondary:hover {
  background-color: var(--secondary-hover);
}

.btn-danger {
  background-color: var(--danger);
  color: #fff;
}
.btn-danger:hover {
  background-color: var(--danger-hover);
}

.btn-outline {
  background-color: transparent;
  border: 1px solid var(--border);
  color: var(--text-main);
}
.btn-outline:hover {
  background-color: #f1f5f9;
}

.btn-text {
  background: transparent;
  color: var(--text-muted);
  padding: 0.4rem 0.6rem;
}
.btn-text:hover {
  color: var(--primary);
}

.btn-small {
  padding: 0.35rem 0.75rem;
  font-size: 0.8rem;
}

.btn-large {
  padding: 1rem 1.75rem;
  font-size: 1.1rem;
  width: 100%;
}

/* ホーム画面 */
.hero-card {
  background-color: var(--card-bg);
  border-radius: var(--radius);
  padding: 2.5rem 2rem;
  text-align: center;
  box-shadow: var(--shadow);
  margin-top: 1rem;
}

.hero-card h2 {
  font-size: 1.6rem;
  margin-bottom: 0.75rem;
}

.hero-card p {
  color: var(--text-muted);
  max-width: 540px;
  margin: 0 auto 2rem;
}

.home-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  max-width: 560px;
  margin: 0 auto;
}

/* 共通セクションヘッダー・カード */
.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}

.card {
  background-color: var(--card-bg);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

/* フォーム */
.form-group {
  margin-bottom: 1.15rem;
}

.form-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.4rem;
  font-size: 0.9rem;
}

.required {
  color: var(--danger);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 0.7rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 1rem;
  font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
}

.form-actions {
  display: flex;
  justify-content: flex-end;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

/* 一覧画面 */
.filter-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: var(--card-bg);
  padding: 0.75rem 1rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  margin-bottom: 1.25rem;
}

.checkbox-label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
}

.music-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
}

.music-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.music-card-header {
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.75rem;
  margin-bottom: 0.75rem;
}

.song-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--primary);
}

.artist-name {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 600;
}

.recommend-point {
  font-size: 0.95rem;
  white-space: pre-wrap;
  margin-bottom: 1rem;
  flex-grow: 1;
}

.music-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  color: var(--text-muted);
  padding-top: 0.75rem;
  border-top: 1px dashed var(--border);
}

.owner-actions {
  display: flex;
  gap: 0.4rem;
  margin-top: 0.75rem;
  justify-content: flex-end;
}

/* トースト通知 */
.toast {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  background-color: #1e293b;
  color: #fff;
  padding: 0.85rem 1.25rem;
  border-radius: 8px;
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.2);
  z-index: 300;
  font-size: 0.9rem;
}

.toast.error {
  background-color: var(--danger);
}

/* モーダル */
.modal {
  position: fixed;
  inset: 0;
  background-color: rgba(15, 23, 42, 0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  z-index: 200;
}

.modal-content {
  width: 100%;
  max-width: 440px;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.btn-close {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-muted);
}

.modal-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1.25rem;
}

.auth-modal-actions {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.loading {
  text-align: center;
  padding: 2rem;
  color: var(--text-muted);
}

/* レスポンシブ対応（モバイル） */
@media (max-width: 600px) {
  .home-actions {
    grid-template-columns: 1fr;
  }
  .hero-card {
    padding: 1.75rem 1.25rem;
  }
  .hero-card h2 {
    font-size: 1.3rem;
  }
}