/* 基本 */

    :root {
        --bg-color: #0b0c10;
        --accent: #45f3ff;
        --accent-glow: rgba(69, 243, 255, 0.4);
        --card-bg: rgba(255, 255, 255, 0.05);
        --card-border: rgba(255, 255, 255, 0.1);
        --text-main: #ffffff;
        --text-muted: #8892b0;
    }

    * {
        box-sizing: border-box;
    }

    body {
        margin: 0;
        padding: 0;
        background: radial-gradient(circle at top center, #1a1a2e 0%, var(--bg-color) 100%);
        color: var(--text-main);
        font-family: Arial, Helvetica, sans-serif;
        min-height: 100vh;
        display: flex;
        flex-direction: column;
        align-items: center;
        transition: background-color 0.5s ease;
    }

    header {
        width: 100%;
        padding: 20px 20px 15px 0;
        margin-bottom: 10px;
        text-align: center;
        background: linear-gradient(to bottom, rgba(11, 12, 16, 0.9), transparent);
        position: sticky;
        top: 0;
        z-index: 10;
        backdrop-filter: blur(10px);
        -webkit-backdrop-filter: blur(10px);
    }

    #fullscreen-btn {
        cursor: pointer;
        border: 0;
        transition: 0.3s;
    }

    #list-container {
        width: 100%;
        max-width: 1400px;
        padding: 20px 40px 100px;
        flex-grow: 1;
    }

    .category-title {
        font-size: 1.5rem;
        color: var(--text-muted);
        margin: 40px 0 20px;
        padding-bottom: 10px;
        border-bottom: 1px solid var(--card-border);
        font-weight: 600;
        letter-spacing: 1px;
        display: flex;
        align-items: center;
    }

    .category-title::before {
        content: '';
        display: inline-block;
        width: 8px;
        height: 24px;
        background: var(--accent);
        margin-right: 12px;
        border-radius: 4px;
        box-shadow: 0 0 10px var(--accent-glow);
    }

    .grid-container {
        display: grid;
        grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
        gap: 25px;
    }

    .item-card {
        background: var(--card-bg);
        border: 1px solid var(--card-border);
        border-radius: 24px;
        padding: 15px;
        display: flex;
        flex-direction: column;
        align-items: center;
        cursor: pointer;
        transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
        text-decoration: none;
        backdrop-filter: blur(5px);
        -webkit-backdrop-filter: blur(5px);
    }

    .item-card:hover {
        transform: translateY(-10px) scale(1.05);
        background: rgba(255, 255, 255, 0.1);
        border-color: var(--accent);
        box-shadow: 0 15px 30px rgba(0, 0, 0, 0.5), 0 0 20px var(--accent-glow);
    }

    .item-card img {
        width: 150px;
        height: 150px;
        border-radius: 20px;
        object-fit: cover;
        box-shadow: 0 8px 16px rgba(0, 0, 0, 0.4);
        transition: transform 0.3s ease;
    }

    .item-card:hover img {
        transform: scale(1.05);
    }

    .item-name {
        margin-top: 15px;
        color: var(--text-main);
        font-size: 1.1rem;
        font-weight: 600;
        text-align: center;
        width: 100%;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
    }

    /* 滾動條美化 */
    ::-webkit-scrollbar {
        width: 8px;
    }

    ::-webkit-scrollbar-track {
        background: var(--bg-color);
    }

    ::-webkit-scrollbar-thumb {
        background: #333;
        border-radius: 4px;
    }

    ::-webkit-scrollbar-thumb:hover {
        background: var(--accent);
    }

    @media (max-width: 768px) {
        .grid-container {
            grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
            gap: 15px;
        }

        .item-card img {
            width: 110px;
            height: 110px;
        }

        #list-container {
            padding: 10px 20px 80px;
        }
    }

    /* 數字鍵盤樣式 */
    .keypad-btn {
        background: rgba(255, 255, 255, 0.05);
        border: 1px solid rgba(255, 255, 255, 0.1);
        color: #fff;
        border-radius: 50%;
        width: 60px;
        height: 60px;
        font-size: 1.5rem;
        font-family: 'Inter', sans-serif;
        font-weight: 600;
        cursor: pointer;
        transition: all 0.2s;
        margin: 0 auto;
        display: flex;
        align-items: center;
        justify-content: center;
    }

    .keypad-btn:hover {
        background: rgba(69, 243, 255, 0.2);
        border-color: var(--accent);
        box-shadow: 0 0 15px var(--accent-glow);
    }

    .keypad-btn:active {
        transform: scale(0.9);
    }

    @keyframes shake {
        0%,
        100% {
            transform: translateX(0);
        }
        25% {
            transform: translateX(-10px);
        }
        50% {
            transform: translateX(10px);
        }
        75% {
            transform: translateX(-10px);
        }
    }

    .shake-animation {
        animation: shake 0.4s;
    }


/* Flip Clock */

    /* 日期顯示區塊 */
    .date-display {
        font-size: 28px;
        letter-spacing: 2px;
        margin-top: 50px;
        margin-bottom: 30px;
        font-weight: 500;
    }

    /* 翻轉時鐘容器 */
    .flip-clock {
        display: flex;
        gap: 20px;
        margin-bottom: 30px;
    }

    /* 單個數字區塊 (時、分、秒) */
    .flip-unit {
        position: relative;
        width: 170px;
        height: 200px;
        background-color: #2a2a2a;
        border-radius: 15px;
        perspective: 1000px;
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.7);
    }

    /* 中間的黑色分隔線 */
    .flip-unit::after {
        content: "";
        position: absolute;
        top: 50%;
        left: 0;
        width: 100%;
        height: 3px;
        background-color: #0b0b0b;
        margin-top: -2px;
        z-index: 5;
    }

    /* 上下半部與翻轉頁片的共通樣式 */
    .top, .bottom, .top-flap, .bottom-flap {
        position: absolute;
        left: 0;
        width: 100%;
        height: 50%; /* 卡片依然是完美的上下各半 */
        background-color: #3d3d3d;
        color: #f5f5f5;
        font-family: Arial, Helvetica, sans-serif;
        font-size: 135px;
        font-weight: bold;
        overflow: hidden;
        backface-visibility: hidden;
        transform-style: preserve-3d;
    }

    /* --- 修正重點：文字獨立包裝並絕對定位 --- */
    .text {
        position: absolute;
        left: 0;
        width: 100%;
        height: 200px;
        line-height: 200px;
        text-align: center;
    }

    /* 上半部 */
    .top, .top-flap {
        top: 0;
        transform-origin: bottom center;
        border-top-left-radius: 15px;
        border-top-right-radius: 15px;
    }
    /* 將上半部的字體向上推 3px */
    .top .text, .top-flap .text {
        top: -3px; 
    }

    /* 下半部 */
    .bottom, .bottom-flap {
        bottom: 0;
        transform-origin: top center;
        border-bottom-left-radius: 15px;
        border-bottom-right-radius: 15px;
    }
    /* 將下半部的字體抵銷外層的 100px 位移，並同時向上推 3px (即 top: -103px) */
    .bottom .text, .bottom-flap .text {
        top: -103px; 
    }

    /* 堆疊層級設定 */
    .top-flap { z-index: 2; }
    .bottom-flap { 
        z-index: 1; 
        transform: rotateX(90deg);
    }

    /* 翻轉動畫 */
    .flip-unit.flipping .top-flap {
        animation: flipDown 0.4s ease-in forwards;
    }
    .flip-unit.flipping .bottom-flap {
        animation: flipUp 0.4s ease-out 0.4s forwards;
    }

    @keyframes flipDown {
        0% { transform: rotateX(0deg); }
        100% { transform: rotateX(-90deg); }
    }

    @keyframes flipUp {
        0% { transform: rotateX(90deg); }
        100% { transform: rotateX(0deg); }
    }


/* 關燈 */

    /* 關燈按鈕樣式 */
    #light-btn {
        cursor: pointer;
        border: 0;
        transition: 0.3s;
    }

    /* 全螢幕黑布，預設隱藏 */
    #dark-overlay {
        position: fixed; /* 固定在螢幕畫面上 */
        top: 0;
        left: 0;
        width: 100vw;
        height: 100vh;
        background-color: #000000;
        z-index: 99999; /* 設定極高的層級，確保蓋住網頁所有原有的 Navbar、Footer 與內容 */
        display: none; /* 預設為不顯示 */
        cursor: pointer; /* 提示使用者點擊 */
        overflow: hidden; /* 防止時鐘超出邊界產生捲動軸 */
    }

    /* 時鐘文字樣式 */
    #clock {
        position: absolute;
        color: #555555; /* 灰色文字 */
        font-size: 5rem;
        font-weight: bold;
        white-space: nowrap;
        user-select: none;
    }

    /* 啟動關燈模式後的狀態 */
    body.dark-mode {
        background-color: #000000;
        cursor: pointer; /* 將游標變為指標，提示使用者點擊可恢復 */
    }

    body.dark-mode #light-btn {
        display: none; /* 隱藏按鈕 */
    }

    body.dark-mode #clock {
        display: block; /* 顯示時鐘 */
    }