* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Noto Serif SC', 'Source Han Serif SC', 'SimSun', serif;
        }
        
        :root {
            --primary: #8e3c36;
            --secondary: #d7b98c;
            --accent: #4a6b3c;
            --light: #f5f0e6;
            --dark: #2c2419;
            --shadow: 0 5px 15px rgba(0,0,0,0.1);
        }
        
        body {
            background: linear-gradient(135deg, #f9f4e9 0%, #e8e1d1 100%);
            color: var(--dark);
            line-height: 1.6;
        }
        
        header {
            background: linear-gradient(to right, var(--primary), #6b2c28);
            color: white;
            padding: 1rem 0;
            position: sticky;
            top: 0;
            z-index: 100;
            box-shadow: var(--shadow);
        }
        
        .container {
            width: 90%;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }
        
        .header-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .logo {
            display: flex;
            align-items: center;
            gap: 15px;
        }
        
        .logo-icon {
            font-size: 2.5rem;
            color: var(--secondary);
        }
        .logo-image {
            width: 48px;
            height: 48px;
        }
        
        .logo-text {
            font-size: 1.8rem;
            font-weight: 700;
            letter-spacing: 1px;
        }
        
        nav ul {
            display: flex;
            list-style: none;
            gap: 25px;
        }
        
        nav a {
            color: white;
            text-decoration: none;
            font-size: 1.1rem;
            padding: 5px 10px;
            border-radius: 4px;
            transition: all 0.3s ease;
        }
        
        nav a:hover, nav a.active {
            background: rgba(255,255,255,0.2);
        }
        
        .hero {
            background: url('https://images.unsplash.com/photo-1603361513131-5e6b5a0b0b0b?ixlib=rb-4.0.3&auto=format&fit=crop&w=1950&q=80') no-repeat center center/cover;
            height: 500px;
            display: flex;
            align-items: center;
            position: relative;
        }
        
        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(44, 36, 25, 0.6);
        }
        
        .hero-content {
            position: relative;
            color: white;
            max-width: 700px;
            padding: 0 20px;
			margin: auto;
        }
        
        .hero h1 {
            font-size: 3.5rem;
            margin-bottom: 20px;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
        }
        
        .hero p {
            font-size: 1.3rem;
            margin-bottom: 30px;
            text-shadow: 1px 1px 2px rgba(0,0,0,0.5);
        }
        
        .btn {
            display: inline-block;
            background: var(--secondary);
            color: var(--dark);
            padding: 12px 30px;
            border-radius: 30px;
            text-decoration: none;
            font-weight: 600;
            transition: all 0.3s ease;
            border: 2px solid var(--secondary);
        }
        
        .btn:hover {
            background: transparent;
            color: var(--secondary);
            transform: translateY(-3px);
        }
        
        section {
            padding: 80px 0;
        }
        
        .section-title {
            text-align: center;
            margin-bottom: 60px;
            position: relative;
        }
        
        .section-title h2 {
            font-size: 2.5rem;
            color: var(--primary);
            display: inline-block;
            padding: 0 20px;
            background: linear-gradient(to right, transparent, var(--light), transparent);
        }
        
        .section-title::before, .section-title::after {
            content: '';
            position: absolute;
            top: 50%;
            width: 30%;
            height: 2px;
            background: var(--secondary);
        }
        
        .section-title::before {
            left: 0;
        }
        
        .section-title::after {
            right: 0;
        }
        
        .intro-content {
            display: flex;
            gap: 40px;
            align-items: center;
        }
        
        .intro-text {
            flex: 1;
        }
        
        .intro-text h3 {
            font-size: 1.8rem;
            margin-bottom: 20px;
            color: var(--accent);
        }
        
        .intro-image {
            flex: 1;
            border-radius: 10px;
            overflow: hidden;
            box-shadow: var(--shadow);
        }
        
        .intro-image img {
            width: 100%;
            height: auto;
            display: block;
            transition: transform 0.5s ease;
        }
        
        .intro-image:hover img {
            transform: scale(1.05);
        }
        
        .theory-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 30px;
        }
        
        .theory-card {
            background: white;
            border-radius: 10px;
            overflow: hidden;
            box-shadow: var(--shadow);
            transition: transform 0.3s ease;
        }
        
        .theory-card:hover {
            transform: translateY(-10px);
        }
        
        .card-header {
            background: var(--primary);
            color: white;
            padding: 20px;
            text-align: center;
            font-size: 1.4rem;
        }
        
        .card-body {
            padding: 25px;
        }
        
        .card-body h4 {
            color: var(--accent);
            margin-bottom: 15px;
            font-size: 1.3rem;
        }
        
        .card-body ul {
            padding-left: 20px;
            margin: 15px 0;
        }
        
        .card-body li {
            margin-bottom: 8px;
        }
        
        .calculator {
            background: white;
            border-radius: 10px;
            padding: 40px;
            max-width: 600px;
            margin: 0 auto;
            box-shadow: var(--shadow);
        }
        
        .calculator h3 {
            text-align: center;
            color: var(--primary);
            margin-bottom: 30px;
        }
        
        .form-group {
            margin-bottom: 20px;
        }
        
        .form-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 600;
            color: var(--dark);
        }
        
        .form-group input, .form-group select {
            width: 100%;
            padding: 12px;
            border: 1px solid #ddd;
            border-radius: 5px;
            font-size: 1rem;
        }
        
        .result {
            margin-top: 30px;
            padding: 20px;
            background: var(--light);
            border-radius: 8px;
            text-align: center;
            display: none;
        }
        
        .result h4 {
            color: var(--primary);
            margin-bottom: 15px;
        }
        
        .timeline {
            position: relative;
            max-width: 800px;
            margin: 50px auto;
        }
        
        .timeline::after {
            content: '';
            position: absolute;
            width: 4px;
            background-color: var(--secondary);
            top: 0;
            bottom: 0;
            left: 50%;
            margin-left: -2px;
        }
        
        .timeline-item {
            padding: 20px 40px;
            position: relative;
            width: 50%;
            box-sizing: border-box;
        }
        
        .timeline-item:nth-child(odd) {
            left: 0;
        }
        
        .timeline-item:nth-child(even) {
            left: 50%;
        }
        
        .timeline-content {
            padding: 20px;
            background: white;
            border-radius: 10px;
            box-shadow: var(--shadow);
        }
        
        .timeline-content h4 {
            color: var(--accent);
            margin-bottom: 10px;
        }
        
        .timeline-item::after {
            content: '';
            position: absolute;
            width: 20px;
            height: 20px;
            background-color: var(--primary);
            border: 4px solid var(--secondary);
            top: 30px;
            border-radius: 50%;
            z-index: 1;
        }
        
        .timeline-item:nth-child(odd)::after {
            right: -12px;
        }
        
        .timeline-item:nth-child(even)::after {
            left: -12px;
        }
        
        footer {
            background: var(--dark);
            color: var(--light);
            padding: 50px 0 20px;
        }
        
        .footer-content {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 30px;
            margin-bottom: 40px;
        }
        
        .footer-column h3 {
            color: var(--secondary);
            margin-bottom: 20px;
            font-size: 1.4rem;
        }
        
        .footer-column ul {
            list-style: none;
        }
        
        .footer-column ul li {
            margin-bottom: 10px;
        }
        
        .footer-column a {
            color: #ccc;
            text-decoration: none;
            transition: color 0.3s ease;
        }
        
        .footer-column a:hover {
            color: var(--secondary);
        }
        
        .copyright {
            text-align: center;
            padding-top: 20px;
            border-top: 1px solid rgba(255,255,255,0.1);
            color: #aaa;
        }
        
        @media (max-width: 768px) {
            .header-content {
                flex-direction: column;
                gap: 20px;
            }
            
            .hero {
                height: 400px;
            }
            
            .hero h1 {
                font-size: 2.5rem;
            }
            
            .intro-content {
                flex-direction: column;
            }
            
            .timeline::after {
                left: 31px;
            }
            
            .timeline-item {
                width: 100%;
                padding-left: 70px;
                padding-right: 25px;
                left: 0 !important;
            }
            
            .timeline-item::after {
                left: 20px !important;
            }
        }