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

        :root {
            --primary-color: #2c3e50;
            --secondary-color: #3498db;
            --accent-color: #e74c3c;
            --light-bg: #f8f9fa;
            --border-color: #dee2e6;
            --text-color: #333;
            --shadow: 0 2px 10px rgba(0,0,0,0.1);
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
            line-height: 1.6;
            color: var(--text-color);
            background-color: #fff;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 15px;
        }

        /* Header */
        header {
            background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
            color: white;
            padding: 20px 0;
            box-shadow: var(--shadow);
            position: sticky;
            top: 0;
            z-index: 1000;
        }

        .header-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
        }

        h1 {
            font-size: 1.5rem;
            font-weight: 700;
        }

        nav {
            display: flex;
            gap: 20px;
            flex-wrap: wrap;
        }

        nav a {
            color: white;
            text-decoration: none;
            padding: 5px 10px;
            border-radius: 5px;
            transition: background 0.3s;
        }

        nav a:hover {
            background: rgba(255,255,255,0.1);
        }

        /* Main Content */
        main {
            padding: 30px 0;
        }

        .intro-section {
            text-align: center;
            margin-bottom: 40px;
            padding: 20px;
            background: var(--light-bg);
            border-radius: 10px;
        }

        .intro-section h2 {
            color: var(--primary-color);
            margin-bottom: 15px;
            font-size: 2rem;
        }

        .intro-section p {
            max-width: 800px;
            margin: 0 auto;
            color: #666;
        }

        /* Calculator Section */
        .calculator-section {
            background: white;
            border-radius: 10px;
            padding: 30px;
            box-shadow: var(--shadow);
            margin-bottom: 40px;
        }

        .form-grid {
            display: grid;
            gap: 25px;
            margin-bottom: 30px;
        }

        .form-group {
            display: flex;
            flex-direction: column;
        }

        label {
            font-weight: 600;
            margin-bottom: 8px;
            color: var(--primary-color);
        }

        input, select {
            padding: 12px;
            border: 1px solid var(--border-color);
            border-radius: 5px;
            font-size: 16px;
            transition: border-color 0.3s;
            background: white;
        }

        input:focus, select:focus {
            outline: none;
            border-color: var(--secondary-color);
        }

        .input-with-unit {
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .input-with-unit input {
            flex: 1;
        }

        .unit {
            color: #666;
            font-size: 14px;
        }

        /* Roof Parameters */
        .roof-params {
            display: grid;
            gap: 20px;
            grid-template-columns: 1fr;
        }

        .checkbox-group {
            display: flex;
            align-items: center;
            gap: 10px;
            padding: 10px;
            background: var(--light-bg);
            border-radius: 5px;
        }

        .checkbox-group input[type="checkbox"] {
            width: 20px;
            height: 20px;
            cursor: pointer;
        }

        /* Buttons */
        .btn {
            padding: 12px 30px;
            border: none;
            border-radius: 5px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s;
            display: inline-block;
        }

        .btn-primary {
            background: var(--secondary-color);
            color: white;
        }

        .btn-primary:hover {
            background: #2980b9;
            transform: translateY(-2px);
            box-shadow: 0 4px 15px rgba(52, 152, 219, 0.3);
        }

        .btn-secondary {
            background: var(--accent-color);
            color: white;
            margin-left: 10px;
        }

        .btn-secondary:hover {
            background: #c0392b;
        }

        .btn-group {
            display: flex;
            gap: 15px;
            justify-content: center;
            margin-top: 30px;
            flex-wrap: wrap;
        }

        /* Results Section */
        .results-section {
            display: none;
            background: var(--light-bg);
            border-radius: 10px;
            padding: 30px;
            margin-top: 30px;
            animation: fadeIn 0.5s;
        }

        .results-section.show {
            display: block;
        }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(20px); }
            to { opacity: 1; transform: translateY(0); }
        }

        .results-grid {
            display: grid;
            gap: 20px;
            margin-top: 20px;
        }

        .result-card {
            background: white;
            padding: 20px;
            border-radius: 8px;
            border-left: 4px solid var(--secondary-color);
        }

        .result-card h4 {
            color: var(--primary-color);
            margin-bottom: 15px;
            font-size: 1.1rem;
        }

        .result-item {
            display: flex;
            justify-content: space-between;
            padding: 8px 0;
            border-bottom: 1px solid #eee;
        }

        .result-item:last-child {
            border-bottom: none;
        }

        .result-label {
            color: #666;
        }

        .result-value {
            font-weight: 600;
            color: var(--primary-color);
        }

        /* Info Sections */
        .info-section {
            margin: 40px 0;
            padding: 30px;
            background: white;
            border-radius: 10px;
            box-shadow: var(--shadow);
        }

        .info-section h2 {
            color: var(--primary-color);
            margin-bottom: 20px;
            font-size: 1.8rem;
        }

        .info-section h3 {
            color: var(--secondary-color);
            margin: 20px 0 10px;
        }

        .info-grid {
            display: grid;
            gap: 20px;
            margin-top: 20px;
        }

        .info-card {
            padding: 20px;
            background: var(--light-bg);
            border-radius: 8px;
            transition: transform 0.3s;
        }

        .info-card:hover {
            transform: translateY(-5px);
        }

        /* FAQ Section */
        .faq-item {
            margin-bottom: 20px;
            border-bottom: 1px solid var(--border-color);
            padding-bottom: 20px;
        }

        .faq-question {
            font-weight: 600;
            color: var(--primary-color);
            margin-bottom: 10px;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: space-between;
        }

        .faq-question::after {
            content: '▼';
            font-size: 12px;
            transition: transform 0.3s;
        }

        .faq-question.active::after {
            transform: rotate(180deg);
        }

        .faq-answer {
            color: #666;
            line-height: 1.8;
            display: none;
            padding-top: 10px;
        }

        .faq-answer.show {
            display: block;
        }

        /* Footer */
        footer {
            background: var(--primary-color);
            color: white;
            padding: 30px 0;
            text-align: center;
            margin-top: 60px;
        }

        .footer-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 20px;
        }

        /* Mobile Styles */
        @media (min-width: 768px) {
            h1 {
                font-size: 2rem;
            }

            .form-grid {
                grid-template-columns: repeat(2, 1fr);
            }

            .roof-params {
                grid-template-columns: repeat(2, 1fr);
            }

            .results-grid {
                grid-template-columns: repeat(2, 1fr);
            }

            .info-grid {
                grid-template-columns: repeat(2, 1fr);
            }
        }

        @media (min-width: 1024px) {
            .form-grid {
                grid-template-columns: repeat(3, 1fr);
            }

            .results-grid {
                grid-template-columns: repeat(3, 1fr);
            }

            .info-grid {
                grid-template-columns: repeat(3, 1fr);
            }
        }

        /* Print Styles for PDF */
        @media print {
            body {
                font-size: 12pt;
            }
            
            .no-print {
                display: none !important;
            }
            
            .results-section {
                page-break-inside: avoid;
            }
        }

        /* Loading Spinner */
        .spinner {
            display: none;
            width: 50px;
            height: 50px;
            border: 5px solid var(--light-bg);
            border-top: 5px solid var(--secondary-color);
            border-radius: 50%;
            animation: spin 1s linear infinite;
            margin: 20px auto;
        }

        .spinner.show {
            display: block;
        }

        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }
        @media (max-width: 767.98px) {
  footer .footer-content {
    justify-content: center;
  }
}
        /* --- MOBILE FULL-BLEED ДЛЯ РЕЗУЛЬТАТОВ --- */
@media (max-width: 767.98px) {
  .results-section {
    /* выходим из .container на всю ширину вьюпорта */
    margin-left: calc(50% - 50vw);
    margin-right: calc(50% - 50vw);
    width: 100vw;

    /* аккуратные отступы внутри и ровные края */
    padding-left: 15px;
    padding-right: 15px;
    border-radius: 0;
  }

  /* на мобильных гарантируем одну колонку */
  .results-grid {
    grid-template-columns: 1fr;
  }
}