/* === 基础重置与背景设定 === */
        body, html {
            margin: 0;
            padding: 0;
            width: 100%;
            height: 100%;
            background-color: #03040a; 
            font-family: 'Helvetica Neue', Arial, sans-serif;
            color: #ffffff;
            overflow-x: hidden;
        }

        /* 极弱粒子背景 */
        #particles-canvas {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: 1;
            opacity: 0.4;
            pointer-events: none;
        }

        /* 主体内容容器 */
        .container {
            position: relative;
            z-index: 10;
            max-width: 900px;
            margin: 0 auto;
            padding: 30px 20px;
            box-sizing: border-box;
            display: flex;
            flex-direction: column;
            gap: 25px;
        }

        /* 顶部导航与语言切换 */
        .header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            border-bottom: 1px solid rgba(255, 255, 255, 0.1);
            padding-bottom: 15px;
        }

        .header-left h1 {
            font-size: 22px;
            font-weight: 300;
            letter-spacing: 2px;
            margin: 0;
            color: #ffda99;
            text-shadow: 0 0 20px rgba(255, 200, 100, 0.3);
        }

        .lang-switcher {
            margin-top: 8px;
            font-size: 13px;
            color: rgba(255, 255, 255, 0.4);
            letter-spacing: 1px;
        }

        .lang-btn {
            cursor: pointer;
            transition: color 0.3s;
        }

        .lang-btn:hover, .lang-btn.active {
            color: #ffda99;
            font-weight: bold;
        }

        .btn-base {
            text-decoration: none;
            color: #ffffff;
            font-size: 14px;
            letter-spacing: 1px;
            padding: 8px 20px;
            border: 1px solid rgba(255, 255, 255, 0.2);
            border-radius: 20px;
            background: rgba(255, 255, 255, 0.05);
            backdrop-filter: blur(4px); 
            -webkit-backdrop-filter: blur(4px);
            transition: all 0.3s ease;
            cursor: pointer;
            outline: none;
        }

        .btn-base:hover {
            border-color: rgba(255, 200, 100, 0.6);
            color: #ffda99;
            background: rgba(255, 200, 100, 0.1);
            box-shadow: 0 0 15px rgba(255, 150, 0, 0.2);
        }

        /* === 设置与计时器区域 === */
        .main-panel {
            background: rgba(255, 255, 255, 0.03);
            border: 1px solid rgba(255, 255, 255, 0.1);
            border-radius: 12px;
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            padding: 30px 20px;
            text-align: center;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
        }

        /* 容器容量设置区 */
        .volume-config {
            display: flex;
            flex-direction: column;
            align-items: center;
            margin-bottom: 25px;
            padding-bottom: 20px;
            border-bottom: 1px dashed rgba(255, 255, 255, 0.1);
        }

        .volume-config label {
            font-size: 14px;
            color: #aaaaaa;
            letter-spacing: 1px;
            margin-bottom: 15px;
        }

        .vol-input-wrapper { margin-bottom: 12px; }

        .quick-btn-wrapper {
            display: flex;
            gap: 10px;
            justify-content: center;
            flex-wrap: wrap;
        }

        .vol-input, .quick-btn {
            width: 72px;
            height: 42px;
            box-sizing: border-box;
            background: rgba(255, 255, 255, 0.05);
            border: 1px solid rgba(255, 255, 255, 0.2);
            color: #ffffff;
            border-radius: 6px;
            font-size: 16px;
            text-align: center;
            outline: none;
            transition: all 0.2s;
            padding: 0;
            font-family: inherit;
        }

        .vol-input { border-color: rgba(255, 200, 100, 0.5); color: #ffda99; }
        .vol-input:focus { background: rgba(255, 200, 100, 0.1); box-shadow: 0 0 10px rgba(255, 150, 0, 0.2); }
        .quick-btn { cursor: pointer; }
        .quick-btn:hover, .quick-btn.active { border-color: #ffda99; color: #ffda99; background: rgba(255, 200, 100, 0.15); }

        .vol-input::-webkit-outer-spin-button, .vol-input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
        .vol-input[type=number] { -moz-appearance: textfield; }

        /* === 读数显示区 === */
        .display-group {
            margin-bottom: 30px;
            display: flex;
            flex-direction: column;
            gap: 5px; 
        }

        #time-display, #flow-display {
            font-size: 4.5rem;
            font-family: 'Courier New', Courier, monospace; 
            font-weight: 300;
            font-variant-numeric: tabular-nums;
            line-height: 1.1;
        }

        #time-display { color: #ffffff; text-shadow: 0 0 20px rgba(255, 255, 255, 0.3); }
        #flow-display { color: #ffda99; text-shadow: 0 0 20px rgba(255, 200, 100, 0.3); }
        .unit-sec { font-size: 1.5rem; color: #aaaaaa; text-shadow: none; }

        .timer-controls { display: flex; justify-content: center; gap: 20px; }
        .timer-controls button { padding: 12px 35px; font-size: 16px; }

        #btn-start { border-color: rgba(100, 255, 100, 0.4); color: #aaffaa; }
        #btn-start:hover { background: rgba(100, 255, 100, 0.1); border-color: #88ff88; box-shadow: 0 0 15px rgba(100, 255, 100, 0.2); }
        #btn-stop { border-color: rgba(255, 200, 100, 0.4); color: #ffda99; }
        #btn-stop:hover:not(:disabled) { background: rgba(255, 200, 100, 0.1); border-color: #ffda99; box-shadow: 0 0 15px rgba(255, 200, 100, 0.2); }
        #btn-stop:disabled { opacity: 0.3; cursor: not-allowed; }

        /* === 数据表格区域 === */
        .table-wrapper {
            background: rgba(255, 255, 255, 0.03);
            border: 1px solid rgba(255, 255, 255, 0.1);
            border-radius: 12px;
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            overflow-x: auto; 
        }

        table { width: 100%; border-collapse: collapse; text-align: center; min-width: 600px; }
        th, td { padding: 14px 10px; border-bottom: 1px solid rgba(255, 255, 255, 0.05); }
        th { font-weight: 400; color: #ffda99; font-size: 14px; background: rgba(0, 0, 0, 0.2); }
        td { font-weight: 300; font-size: 15px; color: #e0e0e0; }
        td.highlight-flow { color: #ffda99; font-weight: bold; font-family: 'Courier New', Courier, monospace; }

        .table-footer { display: flex; justify-content: flex-end; padding: 15px; }

        /* === 响应式 === */
        @media (max-width: 768px) {
            #time-display, #flow-display { 
                font-size: clamp(3.2rem, 15vw, 4.5rem); 
                width: 100%;
                text-align: center;
            }
            .timer-controls { flex-direction: column; gap: 15px; }
            .timer-controls button { width: 100%; }
        }