/* ========================================
   リセット & 基本設定
   ======================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: system-ui, "Yu Gothic", "Hiragino Sans", "Meiryo", sans-serif;
    background-color: #f5f2ef;
    color: #5e443a;
    overflow-x: hidden;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* ========================================
   メインコンテナ
   ======================================== */
.container {
    width: 100%;
    max-width: 1200px;
    padding: 20px;
    position: relative;
    z-index: 1;
}

/* ========================================
   ヘッダー
   ======================================== */
.header {
    text-align: center;
    margin-bottom: 20px;
}

.header h1 {
    font-size: 2rem;
    color: #5e443a;
    margin-bottom: 10px;
    font-weight: 600;
    letter-spacing: 0.05em;
}

.header .subtitle {
    font-size: 1rem;
    color: #a97b60;
    font-weight: 300;
}

/* ========================================
   カードコンテナ
   ======================================== */
.card-container {
    position: relative;
    width: 100%;
    height: 500px;
    margin: 0 auto 20px;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* ========================================
   カード基本スタイル
   ======================================== */
.card {
    position: absolute;
    width: 200px;
    height: 350px;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    border-radius: 12px;
    box-shadow: none;
    cursor: pointer;
    transform-style: preserve-3d;
    transition: all 1.5s ease-out;
    backface-visibility: hidden;
}

/* 初期状態: 中央に重ねる */
.card.initial {
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: var(--card-z-index, 1);
}

/* 展開状態: 円形配置 */
.card.expanded {
    left: var(--card-x);
    top: var(--card-y);
    transform: translate(-50%, -50%);
    transition: all 1.5s ease-out var(--expand-delay);
}

/* 回転アニメーション */
.card.spinning {
    animation: spin-rotation var(--spin-duration) ease-in-out;
}

@keyframes spin-rotation {
    from {
        left: var(--card-x);
        top: var(--card-y);
        transform: translate(-50%, -50%) rotate(0deg);
    }
    to {
        left: var(--card-x);
        top: var(--card-y);
        transform: translate(-50%, -50%) rotate(var(--spin-degrees));
    }
}

/* フェードアウト（選ばれなかったカード） */
.card.fade-out {
    opacity: 0;
    transition: opacity 1s ease-out;
    pointer-events: none;
}

/* 選ばれたカード: 中央へ移動・拡大 */
.card.selected {
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(1.8);
    z-index: 100;
    transition: all 0.8s cubic-bezier(0.4, 0.0, 0.2, 1);
}

/* カード反転アニメーション */
.card.flip {
    animation: flip-card 0.8s cubic-bezier(0.4, 0.0, 0.2, 1) forwards;
}

@keyframes flip-card {
    0% {
        transform: translate(-50%, -50%) scale(1.8) rotateY(0deg);
    }
    100% {
        transform: translate(-50%, -50%) scale(1.8) rotateY(180deg);
    }
}

/* 逆位置のカード */
.card.reversed {
    transform: translate(-50%, -50%) scale(1.8) rotateY(180deg) rotate(180deg) !important;
}

/* カードの表面（反転後に表示） */
.card .card-front {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    transform: rotateY(180deg);
    background-size: cover;
    background-position: center;
    border-radius: 12px;
}

/* ========================================
   結果表示エリア
   ======================================== */
.result-area {
    text-align: center;
    min-height: 80px;
    margin-bottom: 15px;
}

.card-name {
    font-size: 1.8rem;
    font-weight: 600;
    color: #5e443a;
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.5s ease-out;
    letter-spacing: 0.1em;
}

.card-name.show {
    opacity: 1;
    transform: translateY(0);
}

/* ========================================
   ボタンエリア
   ======================================== */
.button-area {
    text-align: center;
    position: relative;
    z-index: 2;
    margin-bottom: 20px;
}

.btn-start,
.btn-retry {
    background-color: #ebe3dd;
    color: #5e443a;
    font-size: 18px;
    padding: 15px 40px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: all 0.2s ease-out;
    font-family: inherit;
    font-weight: 500;
    letter-spacing: 0.05em;
}

.btn-start:hover,
.btn-retry:hover {
    transform: scale(1.05);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.btn-start:active,
.btn-retry:active {
    transform: scale(0.98);
}

.btn-start:focus,
.btn-retry:focus {
    outline: 2px solid #a97b60;
    outline-offset: 2px;
}

.btn-retry {
    color: #a97b60;
    opacity: 0;
    transition: opacity 0.5s ease-in;
}

.btn-retry.show {
    opacity: 1;
}

/* ========================================
   ローディング表示
   ======================================== */
.loading {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    z-index: 1000;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 4px solid #ebe3dd;
    border-top: 4px solid #a97b60;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 15px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.loading p {
    font-size: 1rem;
    color: #5e443a;
}

/* ========================================
   背景オーバーレイ
   ======================================== */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0);
    transition: background-color 0.5s ease-out;
    pointer-events: none;
    z-index: 0;
}

.overlay.active {
    background-color: rgba(0, 0, 0, 0.5);
    pointer-events: auto;
}

/* ========================================
   レスポンシブデザイン: タブレット
   ======================================== */
@media (max-width: 768px) {
    .header h1 {
        font-size: 1.6rem;
    }

    .header .subtitle {
        font-size: 0.9rem;
    }

    .card-container {
        height: 400px;
    }

    .card {
        width: 150px;
        height: 262px;
    }

    .card-name {
        font-size: 1.5rem;
    }

    .btn-start,
    .btn-retry {
        font-size: 16px;
        padding: 12px 35px;
    }
}

/* ========================================
   レスポンシブデザイン: スマートフォン
   ======================================== */
@media (max-width: 480px) {
    .container {
        padding: 15px;
    }

    .header h1 {
        font-size: 1.4rem;
    }

    .header .subtitle {
        font-size: 0.85rem;
    }

    .button-area {
        margin-bottom: 80px;
    }

    .card-container {
        height: 350px;
    }

    .card {
        width: 120px;
        height: 210px;
    }

    /* 初期状態のカードだけ2倍に拡大 */
    .card.initial {
        transform: translate(-50%, -50%) scale(2);
    }

    .card.selected {
        transform: translate(-50%, -50%) scale(1.5);
    }

    .card-name {
        font-size: 1.3rem;
    }

    .btn-start,
    .btn-retry {
        font-size: 15px;
        padding: 12px 30px;
    }
}

/* ========================================
   アクセシビリティ: アニメーション削減
   ======================================== */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}