/* --- 1. 全域變數與主題系統 --- */
:root {
    --bg: radial-gradient(circle at center, #1b2735 0%, #090a0f 100%);
    --paper: #f9f4e8;
    --paper-img: url('https://www.transparenttextures.com/patterns/paper.png');
    --text-main: #3d2b1f;
    --gold: #d4af37;
    --accent: #6d4c41;
    --item-bg: #ffffff;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --shadow: 0 10px 30px rgba(0,0,0,0.4);
    --modal-blur: 0px;
}

/* 🔮 星雲主題 */
body[data-theme='nebula'] {
    --bg: linear-gradient(135deg, #2d3436 0%, #000000 100%), 
          radial-gradient(circle at 20% 30%, #6c5ce7 0%, transparent 40%),
          radial-gradient(circle at 80% 70%, #00cec9 0%, transparent 40%);
    --paper: rgba(15, 15, 30, 0.8);
    --paper-img: none;
    --text-main: #e0e0ff;
    --gold: #a29bfe;
    --accent: #00cec9;
    --item-bg: rgba(255, 255, 255, 0.1);
    --modal-blur: 15px;
}

/* 📜 古書主題 */
body[data-theme='oldbook'] {
    --bg: #1a0f0a;
    --paper: #d4b483;
    --paper-img: url('https://www.transparenttextures.com/patterns/parchment.png');
    --text-main: #3e2723;
    --gold: #795548;
    --accent: #5d4037;
    --item-bg: rgba(0,0,0,0.05);
}

/* ☀️ 白天主題 */
body[data-theme='day'] {
    --bg: linear-gradient(135deg, #e0eafc 0%, #cfdef3 100%);
    --paper: #ffffff;
    --text-main: #2c3e50;
    --gold: #3498db;
    --accent: #2980b9;
    --item-bg: #f8f9fa;
}

/* --- 2. 基礎佈局 --- */
* { box-sizing: border-box; font-family: 'Noto Serif TC', serif; }

body {
    background: var(--bg);
    margin: 0; height: 100vh;
    display: flex; justify-content: center; align-items: center;
    overflow: hidden; transition: background 0.8s ease;
}

.stars {
    position: absolute; width: 100%; height: 100%;
    background: url('https://www.transparenttextures.com/patterns/stardust.png');
    opacity: 0.3; pointer-events: none;
}

.book-wrapper { 
    width: 95%; max-width: 450px; height: 85vh; 
    perspective: 1500px; filter: drop-shadow(var(--shadow));
}

.page {
    position: absolute; width: 100%; height: 100%;
    background-color: var(--paper); background-image: var(--paper-img);
    border-radius: 2px 15px 15px 2px;
    padding: 25px; display: none; 
    color: var(--text-main); transition: var(--transition);
    box-shadow: inset 5px 0 15px rgba(0,0,0,0.1);
    overflow: hidden; /* 重要：防止頁面本身溢出 */
}

.page.active { display: flex; flex-direction: column; animation: pageFadeIn 0.6s ease forwards; }

@keyframes pageFadeIn {
    from { opacity: 0; transform: rotateY(-15deg); }
    to { opacity: 1; transform: rotateY(0deg); }
}

/* --- 3. 封面優化 (解決太擠的問題) --- */
.front-cover {
    display: flex; flex-direction: column;
    align-items: center; justify-content: center; /* 垂直置中 */
    height: 100%; text-align: center;
}

.emboss-logo { font-size: 2rem; margin-bottom: 10px; color: var(--gold); }
.museum-title { font-size: 2.2rem; margin: 0 0 20px 0; letter-spacing: 2px; }

.theme-switcher { margin: 20px 0 40px 0; display: flex; gap: 12px; }
.theme-switcher button {
    background: rgba(255,255,255,0.1); border: 1px solid var(--gold);
    color: var(--gold); width: 38px; height: 38px; border-radius: 50%;
    cursor: pointer; transition: var(--transition); font-size: 1.1rem;
}
.theme-switcher button:hover { transform: scale(1.1); background: var(--gold); color: white; }

.magic-btn {
    background: var(--text-main); color: var(--gold);
    border: 1px solid var(--gold); padding: 12px 30px;
    font-size: 1.1rem; cursor: pointer; border-radius: 4px;
    font-weight: bold; width: 80%; max-width: 250px;
    transition: var(--transition);
}
.magic-btn:hover { transform: translateY(-2px); box-shadow: 0 5px 15px rgba(212,175,55,0.3); }

/* --- 4. 內頁佈局優.化 (解決內容溢出的問題) --- */
.page-content {
    display: flex; flex-direction: column;
    height: 100%; width: 100%;
}

.page-title { 
    font-family: 'Cinzel', serif; border-bottom: 2px solid var(--gold); 
    padding-bottom: 8px; margin-bottom: 15px; font-size: 1.5rem;
}

/* 核心：讓清單佔據剩餘空間並可捲動 */
.custom-scroll {
    flex: 1; overflow-y: auto;
    margin: 10px 0; padding-right: 5px;
}

.custom-scroll::-webkit-scrollbar { width: 4px; }
.custom-scroll::-webkit-scrollbar-thumb { background: var(--gold); border-radius: 10px; }

.btn-row {
    margin-top: auto; padding-top: 15px;
    display: flex; justify-content: space-between; align-items: center;
    border-top: 1px solid rgba(212, 175, 55, 0.1);
}

/* --- 5. 元件樣式 --- */
.story-item {
    background: var(--item-bg); padding: 15px; margin-bottom: 12px;
    border-radius: 8px; border-left: 4px solid var(--gold);
    border: 1px solid rgba(212, 175, 55, 0.1);
    transition: var(--transition); cursor: pointer;
}
.story-item:hover { transform: translateX(5px); background: rgba(212, 175, 55, 0.05); }

.input-group { margin-bottom: 12px; }
.input-group label { display: block; font-size: 0.85rem; margin-bottom: 4px; opacity: 0.8; }

textarea, input, select {
    width: 100%; background: rgba(255,255,255,0.2);
    border: 1px solid rgba(212, 175, 55, 0.4); color: var(--text-main);
    padding: 10px; border-radius: 6px; outline: none;
}
textarea { height: 120px; resize: none; }

.gold-btn { background: var(--gold); color: white; border: none; padding: 10px 20px; border-radius: 4px; cursor: pointer; font-weight: bold; }
.text-btn { background: none; border: none; color: var(--accent); text-decoration: underline; cursor: pointer; font-size: 0.9rem; }

/* --- 6. Modal & Toast --- */
.modal {
    display: none; position: fixed; top:0; left:0; width: 100%; height: 100%;
    background: rgba(0,0,0,0.85); backdrop-filter: blur(var(--modal-blur));
    z-index: 1000; justify-content: center; align-items: center;
}
.modal-card {
    background: var(--paper); background-image: var(--paper-img);
    width: 90%; max-width: 400px; padding: 30px; border-radius: 15px;
    color: var(--text-main); position: relative;
}
.close-x { position: absolute; right: 15px; top: 10px; font-size: 1.8rem; cursor: pointer; opacity: 0.5; }

#toast {
    position: fixed; bottom: 30px; left: 50%; transform: translateX(-50%) translateY(100px);
    background: var(--gold); color: white; padding: 10px 25px; border-radius: 50px;
    transition: transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 2000; box-shadow: 0 5px 15px rgba(0,0,0,0.3); font-weight: bold;
}
#toast.show { transform: translateX(-50%) translateY(0); }