* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            padding: 20px;
        }

        .container {
            max-width: 800px;
            margin: 0 auto;
            background: white;
            border-radius: 20px;
            box-shadow: 0 20px 40px rgba(0,0,0,0.1);
            overflow: hidden;
        }

        .header {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            padding: 30px;
            text-align: center;
        }

        .header h1 {
            font-size: 2.5em;
            margin-bottom: 10px;
            font-weight: 300;
        }

        .header p {
            font-size: 1.1em;
            opacity: 0.9;
        }

        .content {
            padding: 30px;
        }

        .mode-selector {
            display: flex;
            gap: 10px;
            margin-bottom: 30px;
            background: #f8f9fa;
            padding: 15px;
            border-radius: 10px;
        }

        .mode-btn {
            flex: 1;
            padding: 12px 20px;
            border: 2px solid #e1e5e9;
            background: white;
            border-radius: 8px;
            cursor: pointer;
            transition: all 0.3s ease;
            font-weight: 600;
            color: #666;
        }

        .mode-btn.active {
            background: #667eea;
            color: white;
            border-color: #667eea;
        }

        .mode-btn:hover {
            border-color: #667eea;
        }

        .input-section {
            margin-bottom: 25px;
        }

        .input-section h3 {
            color: #333;
            margin-bottom: 15px;
            font-size: 1.3em;
        }

        .input-row {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 15px;
            margin-bottom: 20px;
        }

        .time-input {
            display: grid;
            grid-template-columns: 1fr 1fr 1fr;
            gap: 10px;
        }

        .date-input {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 15px;
        }

        select, input {
            width: 100%;
            padding: 12px 15px;
            border: 2px solid #e1e5e9;
            border-radius: 10px;
            font-size: 1em;
            transition: all 0.3s ease;
            background: white;
        }

        select:focus, input:focus {
            outline: none;
            border-color: #667eea;
            box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
        }

        .calculate-btn {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            padding: 15px 30px;
            border-radius: 10px;
            font-size: 1.1em;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            width: 100%;
            margin: 20px 0;
        }

        .calculate-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 10px 20px rgba(102, 126, 234, 0.3);
        }

        .result {
            background: #f8f9fa;
            border-radius: 15px;
            padding: 25px;
            margin-top: 25px;
            border-left: 5px solid #667eea;
        }

        .result h3 {
            color: #333;
            margin-bottom: 15px;
            font-size: 1.3em;
        }

        .duration-display {
            font-size: 2em;
            font-weight: bold;
            color: #667eea;
            text-align: center;
            margin: 15px 0;
            padding: 20px;
            background: white;
            border-radius: 10px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
        }

        .breakdown {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
            gap: 15px;
            margin-top: 20px;
        }

        .breakdown-item {
            background: white;
            padding: 15px;
            border-radius: 10px;
            text-align: center;
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
        }

        .breakdown-value {
            font-size: 1.5em;
            font-weight: bold;
            color: #667eea;
        }

        .breakdown-label {
            color: #666;
            font-size: 0.9em;
            margin-top: 5px;
        }

        .back-link {
            display: inline-block;
            margin-top: 20px;
            color: #667eea;
            text-decoration: none;
            font-weight: 600;
            transition: color 0.3s ease;
        }

        .back-link:hover {
            color: #764ba2;
        }

        .hidden {
            display: none;
        }

        @media (max-width: 768px) {
            .input-row {
                grid-template-columns: 1fr;
            }
            
            .time-input {
                grid-template-columns: 1fr;
            }
            
            .date-input {
                grid-template-columns: 1fr;
            }
            
            .mode-selector {
                flex-direction: column;
            }
            
            .header h1 {
                font-size: 2em;
            }
        }