/* === 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;
        }

        #particles-canvas {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: 1;
            opacity: 0.4;
            pointer-events: none;
        }

        .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;
        }

        /* === 头部与语言切换 === */
        .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);
        }

        /* === 磨砂玻璃卡片通用样式 === */
        .glass-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: 25px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
            margin-bottom: 20px;
        }

        .section-title {
            color: #ffda99;
            font-size: 18px;
            font-weight: 300;
            margin-top: 0;
            margin-bottom: 15px;
            border-left: 3px solid #ffda99;
            padding-left: 10px;
        }

        .text-content {
            font-size: 14px;
            color: #cccccc;
            line-height: 1.6;
            font-weight: 300;
        }

        /* === SVG 示意图区域 === */
        .diagram-container {
            text-align: center;
            padding: 20px 0;
            background: rgba(0, 0, 0, 0.2);
            border-radius: 8px;
            margin-bottom: 15px;
        }

        /* === 公式显示区域 === */
        .formula-box {
            background: rgba(255, 200, 100, 0.05);
            border: 1px dashed rgba(255, 200, 100, 0.3);
            border-radius: 8px;
            padding: 15px;
            text-align: center;
            font-family: 'Courier New', Courier, monospace;
            font-size: 16px;
            color: #ffffff;
            margin: 15px 0;
            overflow-x: auto;
        }

        .formula-box sub, .formula-box sup {
            font-size: 12px;
        }

        /* === 计算器专属样式 === */
        .calc-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
            gap: 20px;
            margin-bottom: 30px;
            align-items: end;
        }

        .input-group {
            display: flex;
            flex-direction: column;
            gap: 8px;
        }

        .input-group label {
            font-size: 13px;
            color: #aaaaaa;
            letter-spacing: 1px;
        }

        .input-group input {
            background: rgba(255, 255, 255, 0.05);
            border: 1px solid rgba(255, 255, 255, 0.2);
            color: #ffffff;
            border-radius: 6px;
            padding: 12px;
            font-size: 18px;
            outline: none;
            transition: all 0.3s;
            font-family: 'Courier New', Courier, monospace;
        }

        .input-group input:focus {
            border-color: #ffda99;
            background: rgba(255, 200, 100, 0.05);
            box-shadow: 0 0 10px rgba(255, 150, 0, 0.2);
        }

        .result-display {
            text-align: center;
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            padding-top: 25px;
        }

        .result-label {
            font-size: 14px;
            color: #aaaaaa;
            margin-bottom: 10px;
            letter-spacing: 2px;
            text-transform: uppercase;
        }

        #flow-result {
            font-size: clamp(3rem, 10vw, 4.5rem);
            font-family: 'Courier New', Courier, monospace;
            font-weight: 700;
            color: #ffda99;
            text-shadow: 0 0 30px rgba(255, 200, 100, 0.4);
            margin: 0;
            line-height: 1.1;
            transition: color 0.3s;
        }

        .unit {
            font-size: 1.5rem;
            color: #aaaaaa;
            font-weight: 300;
            text-shadow: none;
        }

        /* === 响应式 === */
        @media (max-width: 768px) {
            .calc-grid { grid-template-columns: 1fr; gap: 15px; }
            .glass-panel { padding: 15px; }
            .header { flex-direction: column; align-items: flex-start; gap: 15px; }
            .header-left { width: 100%; display: flex; justify-content: space-between; align-items: center; }
            .lang-switcher { margin-top: 0; }
        }