:root {
    --color-bg: #faf8f5;
    --color-bg-alt: #f0ede8;
    --color-text: #1a1a1a;
    --color-text-light: #666;
    --color-primary: #8b7355;
    --color-primary-dark: #6b5a42;
    --color-accent: #c4956a;
    --color-white: #ffffff;
    --color-border: #e0dbd4;
    --color-warm: #f5f0eb;
    --shadow: 0 2px 12px rgba(0,0,0,0.08);
    --radius: 8px;
    --max-width: 1200px;
}

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

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    font-size: 16px;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

/* Navigation */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(250,248,245,0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    z-index: 100;
}

.nav-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo {
    font-size: 24px;
    font-weight: 800;
    color: var(--color-primary-dark);
    text-decoration: none;
    letter-spacing: -0.5px;
}

.nav-links {
    display: flex;
    gap: 32px;
}

.nav-links a {
    color: var(--color-text);
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-links a:hover {
    color: var(--color-primary);
}

/* Hero */
.hero {
    padding: 140px 24px 80px;
    text-align: center;
    background: linear-gradient(180deg, var(--color-bg) 0%, var(--color-warm) 100%);
}

.hero-inner {
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 48px;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 20px;
    letter-spacing: -1px;
}

.hero-sub {
    font-size: 18px;
    color: var(--color-text-light);
    max-width: 600px;
    margin: 0 auto 32px;
}

.hero-cta {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 60px;
}

.btn {
    display: inline-flex;
    align-items: center;
    padding: 14px 32px;
    border-radius: var(--radius);
    font-size: 15px;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    border: none;
    transition: all 0.2s;
}

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

.btn-primary:hover {
    background: var(--color-primary-dark);
}

.btn-secondary {
    background: var(--color-white);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-bg-alt);
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    max-width: 700px;
    margin: 0 auto;
}

.stat {
    text-align: center;
}

.stat-num {
    display: block;
    font-size: 36px;
    font-weight: 800;
    color: var(--color-primary-dark);
    line-height: 1.2;
}

.stat-label {
    font-size: 13px;
    color: var(--color-text-light);
    font-weight: 500;
}

/* Sections */
section {
    padding: 80px 0;
}

section:nth-child(even) {
    background: var(--color-white);
}

h2 {
    font-size: 36px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
    letter-spacing: -0.5px;
}

.section-sub {
    text-align: center;
    color: var(--color-text-light);
    max-width: 600px;
    margin: 0 auto 48px;
    font-size: 17px;
}

/* System / Modular */
.system {
    background: var(--color-bg-alt);
}

.modular-visual {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
    align-items: start;
}

.module-demo {
    background: var(--color-white);
    border-radius: var(--radius);
    padding: 32px;
    box-shadow: var(--shadow);
}

.module-grid {
    display: grid;
    gap: 2px;
    background: var(--color-border);
    border-radius: 4px;
    padding: 2px;
    margin-bottom: 24px;
    min-height: 200px;
}

.module-cell {
    background: var(--color-primary);
    border-radius: 2px;
    min-height: 40px;
    transition: all 0.3s;
}

.module-cell:hover {
    background: var(--color-primary-dark);
}

.module-controls {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.control {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.control label {
    font-weight: 600;
    font-size: 14px;
    min-width: 120px;
}

.control input,
.control select {
    padding: 8px 12px;
    border: 1px solid var(--color-border);
    border-radius: 4px;
    font-size: 14px;
    width: 80px;
}

.control select {
    width: auto;
    min-width: 180px;
}

.dim {
    color: var(--color-text-light);
    font-size: 13px;
}

.warning {
    color: #c0392b;
    font-size: 13px;
    font-weight: 600;
    min-height: 20px;
}

.module-info {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.info-card {
    background: var(--color-white);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
    text-align: center;
}

.info-card h3 {
    font-size: 13px;
    font-weight: 600;
    color: var(--color-text-light);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 8px;
}

.info-card .big {
    font-size: 32px;
    font-weight: 800;
    color: var(--color-primary-dark);
    line-height: 1;
}

.info-card .unit {
    font-size: 13px;
    color: var(--color-text-light);
    margin-top: 4px;
}

/* Calculator */
.calculator {
    background: var(--color-white);
}

.calc-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
    margin-bottom: 48px;
}

.calc-panel {
    background: var(--color-bg);
    border-radius: var(--radius);
    padding: 28px;
}

.calc-panel h3 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--color-primary);
}

.calc-row {
    margin-bottom: 20px;
}

.calc-row label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--color-text-light);
}

.calc-row input[type="range"] {
    width: 100%;
    margin-bottom: 4px;
}

.calc-row select {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--color-border);
    border-radius: 4px;
    font-size: 14px;
    background: var(--color-white);
}

.calc-val {
    font-size: 13px;
    color: var(--color-primary);
    font-weight: 600;
}

.calc-check {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 14px;
}

.calc-check input {
    width: 18px;
    height: 18px;
    accent-color: var(--color-primary);
}

.calc-check label {
    font-size: 14px;
    cursor: pointer;
}

.calc-total {
    background: var(--color-bg-alt);
    border-radius: var(--radius);
    padding: 40px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
    align-items: center;
}

.total-breakdown {
    font-size: 14px;
    line-height: 2;
}

.total-breakdown .break-item {
    display: flex;
    justify-content: space-between;
    border-bottom: 1px solid var(--color-border);
    padding: 4px 0;
}

.total-breakdown .break-total {
    font-weight: 700;
    font-size: 16px;
    border-top: 2px solid var(--color-primary);
    margin-top: 8px;
    padding-top: 8px;
}

.total-sum {
    text-align: center;
}

.total-label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--color-text-light);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 12px;
}

.total-number {
    display: block;
    font-size: 56px;
    font-weight: 800;
    color: var(--color-primary-dark);
    line-height: 1;
    letter-spacing: -2px;
}

.total-per {
    display: block;
    font-size: 16px;
    color: var(--color-text-light);
    margin-top: 8px;
}

/* Materials / Wall */
.materials {
    background: var(--color-bg);
}

.wall-layers {
    max-width: 700px;
    margin: 0 auto 48px;
}

.layer {
    display: flex;
    align-items: flex-start;
    gap: 20px;
    padding: 20px 0;
    border-bottom: 1px solid var(--color-border);
}

.layer-num {
    font-size: 14px;
    font-weight: 800;
    color: var(--color-primary);
    min-width: 28px;
}

.layer-content h4 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 4px;
}

.layer-content p {
    font-size: 14px;
    color: var(--color-text-light);
    margin-bottom: 6px;
}

.layer-spec {
    font-size: 12px;
    font-weight: 600;
    color: var(--color-primary);
    background: var(--color-warm);
    padding: 4px 10px;
    border-radius: 4px;
    display: inline-block;
}

.materials-table {
    background: var(--color-white);
    border-radius: var(--radius);
    padding: 32px;
    box-shadow: var(--shadow);
    overflow-x: auto;
}

.materials-table h3 {
    font-size: 18px;
    margin-bottom: 20px;
}

.materials-table table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
}

.materials-table th {
    text-align: left;
    padding: 12px 8px;
    border-bottom: 2px solid var(--color-border);
    font-weight: 600;
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--color-text-light);
}

.materials-table td {
    padding: 10px 8px;
    border-bottom: 1px solid var(--color-border);
}

.materials-table tr.total td {
    border-top: 2px solid var(--color-primary);
    border-bottom: none;
    padding-top: 12px;
}

/* Science */
.science {
    background: var(--color-white);
}

.data-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
}

.data-card {
    background: var(--color-bg);
    border-radius: var(--radius);
    padding: 32px;
}

.data-card h3 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--color-primary);
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
    margin-bottom: 16px;
}

.data-table td {
    padding: 8px 0;
    border-bottom: 1px solid var(--color-border);
}

.data-table td:last-child {
    text-align: right;
    font-weight: 600;
    color: var(--color-primary-dark);
}

.data-note {
    font-size: 13px;
    color: var(--color-text-light);
    font-style: italic;
}

/* Build Steps */
.build {
    background: var(--color-bg-alt);
}

.build-steps {
    max-width: 800px;
    margin: 0 auto;
}

.step {
    display: flex;
    gap: 24px;
    padding: 28px 0;
    border-bottom: 1px solid var(--color-border);
}

.step-num {
    font-size: 32px;
    font-weight: 800;
    color: var(--color-primary);
    min-width: 48px;
    line-height: 1;
}

.step-content h4 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 8px;
}

.step-content p {
    color: var(--color-text-light);
    margin-bottom: 12px;
    font-size: 15px;
}

.step-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
}

.step-meta span {
    font-size: 12px;
    font-weight: 600;
    color: var(--color-primary);
    background: var(--color-warm);
    padding: 4px 10px;
    border-radius: 4px;
}

.build-summary {
    text-align: center;
    margin-top: 48px;
    padding: 32px;
    background: var(--color-white);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.build-summary h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 12px;
}

.build-summary p {
    color: var(--color-text-light);
    max-width: 600px;
    margin: 0 auto;
}

/* Downloads */
.downloads {
    background: var(--color-white);
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.download-card {
    background: var(--color-bg);
    border-radius: var(--radius);
    padding: 28px;
    text-decoration: none;
    color: inherit;
    transition: transform 0.2s, box-shadow 0.2s;
    border: 1px solid var(--color-border);
}

.download-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow);
}

.download-card h4 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 8px;
}

.download-card p {
    font-size: 14px;
    color: var(--color-text-light);
    margin-bottom: 16px;
}

.download-tag {
    font-size: 12px;
    font-weight: 700;
    color: var(--color-white);
    background: var(--color-primary);
    padding: 4px 10px;
    border-radius: 4px;
    display: inline-block;
}

/* Contact */
.contact {
    background: var(--color-bg-alt);
}

.service-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    margin-bottom: 48px;
}

.service-card {
    background: var(--color-white);
    border-radius: var(--radius);
    padding: 28px;
    box-shadow: var(--shadow);
}

.service-card h4 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 8px;
}

.service-card p {
    font-size: 14px;
    color: var(--color-text-light);
}

.pricing-service {
    text-align: center;
    margin-bottom: 48px;
}

.service-price {
    font-size: 24px;
    font-weight: 700;
}

.service-price strong {
    color: var(--color-primary-dark);
    font-size: 36px;
}

.service-note {
    color: var(--color-text-light);
    font-size: 14px;
    margin-top: 8px;
}

.contact-form {
    max-width: 600px;
    margin: 0 auto;
    background: var(--color-white);
    border-radius: var(--radius);
    padding: 40px;
    box-shadow: var(--shadow);
}

.contact-form h3 {
    text-align: center;
    margin-bottom: 24px;
    font-size: 20px;
}

.form-row {
    display: flex;
    gap: 16px;
    margin-bottom: 16px;
}

.form-row input,
.form-row select,
.contact-form textarea {
    flex: 1;
    padding: 12px;
    border: 1px solid var(--color-border);
    border-radius: 4px;
    font-size: 14px;
    font-family: inherit;
}

.contact-form textarea {
    width: 100%;
    min-height: 120px;
    margin-bottom: 16px;
    resize: vertical;
}

/* Footer */
.footer {
    background: var(--color-text);
    color: var(--color-bg-alt);
    padding: 64px 0 32px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 48px;
    margin-bottom: 48px;
}

.footer-col h4 {
    font-size: 14px;
    font-weight: 700;
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.footer-col p {
    font-size: 14px;
    color: var(--color-text-light);
    line-height: 1.8;
}

.footer-col a {
    display: block;
    color: var(--color-bg-alt);
    text-decoration: none;
    font-size: 14px;
    margin-bottom: 10px;
    opacity: 0.8;
    transition: opacity 0.2s;
}

.footer-col a:hover {
    opacity: 1;
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 24px;
    text-align: center;
}

.footer-bottom p {
    font-size: 12px;
    color: var(--color-text-light);
    opacity: 0.7;
}

/* Responsive */
@media (max-width: 900px) {
    .hero h1 {
        font-size: 32px;
    }
    
    .hero-stats {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .modular-visual {
        grid-template-columns: 1fr;
    }
    
    .calc-grid {
        grid-template-columns: 1fr;
    }
    
    .data-grid {
        grid-template-columns: 1fr;
    }
    
    .download-grid {
        grid-template-columns: 1fr;
    }
    
    .service-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
    
    .calc-total {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 600px) {
    .nav-links {
        display: none;
    }
    
    .hero h1 {
        font-size: 28px;
    }
    
    .hero-stats {
        grid-template-columns: 1fr 1fr;
        gap: 16px;
    }
    
    .stat-num {
        font-size: 28px;
    }
    
    .hero-cta {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .service-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
    }
    
    .form-row {
        flex-direction: column;
    }
    
    .calc-total {
        padding: 24px;
    }
    
    .total-number {
        font-size: 40px;
    }
}