* {
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent; /* 消除手機點擊高光 */
}

body {
    margin: 0;
    padding: 0;
    /* 加入星空背景漸層 */
    background: radial-gradient(ellipse at center 60%, rgba(150, 180, 210, 0.6) 0%, rgba(45, 75, 110, 0.5) 30%, rgba(5, 12, 25, 0.9) 70%), linear-gradient(to bottom, #02050a 0%, #0a1120 50%, #152033 100%);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh; /* 手機端通常為直向 (Portrait) */
    overflow: hidden;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    color: white;
    /* 避免手機瀏覽器滾動溢出 */
    touch-action: none;
    position: relative; /* 為了讓 star-bg 定位 */
}

/* === 星空背景特效 === */
.star-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    pointer-events: none;
    z-index: -1;
}
.star {
    position: absolute;
    background-color: #fff;
    border-radius: 50%;
    animation: twinkle linear infinite;
    box-shadow: 0 0 5px #fff;
}
@keyframes twinkle {
    0% { opacity: 0; transform: scale(0.5); }
    50% { opacity: 1; transform: scale(1.2); }
    100% { opacity: 0; transform: scale(0.5); }
}

/* === 專輯資料夾按鈕 === */
.menu-btn {
    position: fixed;
    top: 50%;
    left: 20px; /* 放在左側邊 */
    transform: translateY(-50%); /* 上下置中 */
    width: 32px;
    height: 32px;
    cursor: pointer;
    z-index: 200; /* 給最高層級，讓它在側邊欄之上一點或可自由覆蓋 */
    transition: transform 0.3s, opacity 0.3s;
}

.menu-btn svg {
    width: 100%;
    height: 100%;
    transition: fill 0.3s ease;
}

.menu-btn.open svg {
    fill: rgba(30, 215, 96, 0.3); /* 打開選單時有底部高光 */
}

/* === 左側抽屜選單 === */
.mobile-menu {
    position: fixed;
    top: 0;
    left: -280px; /* 隱藏於左側 */
    width: 260px;
    height: 100%;
    background: rgba(0, 0, 0, 0.85);
    backdrop-filter: blur(12px);
    z-index: 100;
    padding: 80px 20px 20px;
    transition: left 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 4px 0 15px rgba(0, 0, 0, 0.5);
    overflow-y: auto;
}

.mobile-menu.open {
    left: 0; /* 滑動出 */
}

.mobile-menu h3 {
    color: #1ed760;
    margin-bottom: 20px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding-bottom: 10px;
    font-size: 18px;
}

.mobile-menu ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.mobile-menu li {
    padding: 12px 15px;
    margin-bottom: 8px;
    cursor: pointer;
    border-radius: 8px;
    font-size: 16px;
    color: #b3b3b3;
    transition: background 0.3s, color 0.3s;
}

.mobile-menu li:active, .mobile-menu li:hover {
    background: rgba(255, 255, 255, 0.1);
}

.mobile-menu li.active {
    background: rgba(30, 215, 96, 0.2);
    color: #1ed760;
    font-weight: bold;
}

/* === 遮罩層 === */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    opacity: 0;
    visibility: hidden;
    z-index: 50;
    transition: opacity 0.4s;
}
.overlay.visible {
    opacity: 1;
    visibility: visible;
}

/* === 3D 場景 === */
.scene {
    width: 100%;
    flex: 1; /* 佔滿剩餘高度 */
    perspective: 1000px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.carousel {
    /* 手機版將 CD 縮小以配合垂直螢幕的寬度 */
    width: 140px;
    height: 140px;
    position: relative;
    transform-style: preserve-3d;
    transform: rotateX(0deg); /* 整個面向前面，無 Y 軸傾斜 */
    /* 移除 transition 讓手動滑動更跟手 */
}

.cd-item {
    position: absolute;
    width: 140px;
    height: 140px;
    cursor: pointer;
    transform-style: preserve-3d;
    transition: transform 0.3s, box-shadow 0.3s;
}

.cd-title {
    position: absolute;
    top: -30px;
    left: 0;
    width: 100%;
    text-align: center;
    font-size: 14px;
    font-weight: bold;
    color: #fff;
    text-shadow: 0 2px 4px rgba(0,0,0,0.8);
    transform: translateZ(12px);
    pointer-events: none;
}

.cd-face {
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background-size: cover;
    background-position: center;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.cd-front {
    transform: translateZ(8px);
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
}

.cd-back {
    background-color: #282828;
    transform: rotateY(180deg) translateZ(8px);
}

.cd-top, .cd-bottom, .cd-left, .cd-right {
    background-color: #000000;
}

.cd-top {
    height: 16px;
    transform: rotateX(90deg) translateZ(8px);
    top: -8px;
}
.cd-bottom {
    height: 16px;
    transform: rotateX(-90deg) translateZ(132px);
    top: -8px;
}
.cd-left {
    width: 16px;
    transform: rotateY(-90deg) translateZ(8px);
    left: -8px;
}
.cd-right {
    width: 16px;
    transform: rotateY(90deg) translateZ(132px);
    left: -8px;
}

/* === 漢堡選單(導覽列) 三條線自訂樣式 === */
.custom-toggler .toggler-icon {
  display: block;
  width: 30px;
  height: 2px;
  margin: 6px 0;
  background-color: #fff;
  transition: all 0.3s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.custom-toggler {
  border: none;
}

.custom-toggler:focus {
  box-shadow: none;
  outline: none;
}

.custom-toggler[aria-expanded="true"] .toggler-icon:nth-child(1) {
  transform: rotate(-45deg) translate(-5px, 6px);
}

.custom-toggler[aria-expanded="true"] .toggler-icon:nth-child(2) {
  opacity: 0;
}

.custom-toggler[aria-expanded="true"] .toggler-icon:nth-child(3) {
  transform: rotate(45deg) translate(-5px, -6px);
}

/* === Footer 樣式 === */
footer {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    background-color: #000000;
    color: #B7B7B7;
    display: flex;
    flex-direction: column;   
    justify-content: center;
    align-items: center;
    text-align: center;
    font-size: 12px;
    padding: 10px 0;
    z-index: 100;
}

footer p {
    text-align: center;       
    margin: 0;                
    max-width: 90%;           
    word-wrap: break-word;    
}

footer img {
    margin-top: 5px; 
}