:root {
    --primary-green: #1B6B43;
    --primary-hover: #145233;
    --light-bg: #F8FAF8;
    --card-bg: #FFFFFF;
    --result-bg: #F0F7F3;
    --text-dark: #1F2937;
    --text-muted: #6B7280;
    --border-color: #E5E7EB;
    --badge-bg: #D1E7DD;
    --badge-text: #0F5132;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Inter', sans-serif;
}

body {
    background-color: var(--light-bg);
    color: var(--text-dark);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    background-image: 
        radial-gradient(circle at 10% 20%, rgba(27, 107, 67, 0.05) 0%, transparent 40%),
        radial-gradient(circle at 90% 80%, rgba(27, 107, 67, 0.05) 0%, transparent 40%);
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 8%;
    background: transparent;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-icon {
    width: 32px;
    height: 32px;
}

.logo-text {
    font-weight: 800;
    font-size: 20px;
    color: var(--text-dark);
}

.logo-text span {
    color: var(--primary-green);
}

.nav-links {
    display: flex;
    gap: 30px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-muted);
    font-weight: 500;
    font-size: 15px;
    transition: color 0.2s;
}

.nav-links a.active, .nav-links a:hover {
    color: var(--primary-green);
    font-weight: 600;
}

.btn-primary-nav {
    background-color: var(--primary-green);
    color: white;
    text-decoration: none;
    padding: 10px 20px;
    border-radius: 30px;
    font-weight: 600;
    font-size: 14px;
    transition: background-color 0.2s;
}

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

.main-container {
    max-width: 900px;
    margin: 40px auto;
    padding: 0 20px;
    text-align: center;
    flex: 1;
}

.hero-header .badge {
    color: var(--primary-green);
    font-weight: 700;
    font-size: 12px;
    letter-spacing: 1.5px;
    margin-bottom: 12px;
    display: inline-block;
}

.hero-header h1 {
    font-size: 38px;
    font-weight: 800;
    color: var(--text-dark);
    margin-bottom: 10px;
    letter-spacing: -0.5px;
}

.hero-header p {
    color: var(--text-muted);
    font-size: 16px;
    margin-bottom: 35px;
}

.calculator-card {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.04);
    border: 1px solid rgba(0,0,0,0.03);
}

.tabs {
    display: flex;
    gap: 30px;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 30px;
    padding-bottom: 10px;
}

.tab-btn {
    background: none;
    border: none;
    font-size: 16px;
    font-weight: 600;
    color: var(--text-muted);
    cursor: pointer;
    padding-bottom: 10px;
    position: relative;
}

.tab-btn.active {
    color: var(--primary-green);
}

.tab-btn.active::after {
    content: '';
    position: absolute;
    bottom: -11px;
    left: 0;
    width: 100%;
    height: 3px;
    background-color: var(--primary-green);
    border-radius: 2px;
}

.calculator-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 25px;
    align-items: center;
}

.input-group-container {
    display: flex;
    flex-direction: column;
    gap: 18px;
    text-align: left;
}

.input-field label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 6px;
}

.input-field input {
    width: 100%;
    padding: 14px 16px;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    color: var(--text-dark);
    outline: none;
    transition: border-color 0.2s;
}

.input-field input:focus {
    border-color: var(--primary-green);
}

.btn-calculate {
    background-color: var(--primary-green);
    color: white;
    border: none;
    padding: 16px;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 700;
    cursor: pointer;
    margin-top: 5px;
    transition: background-color 0.2s;
}

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

.result-box {
    background-color: var(--result-bg);
    border-radius: 16px;
    padding: 35px 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 220px;
}

.result-label {
    font-size: 12px;
    font-weight: 700;
    color: var(--text-muted);
    letter-spacing: 1px;
    margin-bottom: 10px;
}

.result-price {
    font-size: 38px;
    font-weight: 800;
    color: var(--primary-green);
    margin-bottom: 8px;
}

.result-savings {
    font-size: 15px;
    color: var(--text-dark);
    margin-bottom: 15px;
}

.result-savings strong {
    color: var(--primary-green);
}

.badge-discount {
    background-color: var(--badge-bg);
    color: var(--badge-text);
    padding: 6px 16px;
    border-radius: 20px;
    font-weight: 700;
    font-size: 14px;
}

.features-bar {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin-top: 40px;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--text-muted);
    font-size: 14px;
    font-weight: 500;
}

.feature-item svg {
    width: 20px;
    height: 20px;
    stroke: var(--primary-green);
}

footer {
    padding: 25px;
    text-align: center;
    color: var(--text-muted);
    font-size: 13px;
}

@media (max-width: 768px) {
    .navbar {
        flex-wrap: wrap;
        padding: 15px 15px;
        gap: 12px;
        justify-content: space-between;
    }

    .nav-links {
        display: flex !important; 
        order: 3;
        width: 100%;
        justify-content: center;
        gap: 20px;
        padding-top: 10px;
        border-top: 1px solid #E5E7EB;
    }

    .nav-links a {
        font-size: 14px;
        padding: 6px 10px;
        font-weight: 600;
    }

    .btn-primary-nav {
        font-size: 13px;
        padding: 8px 14px;
    }

    .hero-header h1 {
        font-size: 26px;
        line-height: 1.3;
    }

    .calculator-card {
        padding: 20px 15px;
    }

    .calculator-content {
        grid-template-columns: 1fr;
    }

    .features-bar {
        flex-direction: column;
        gap: 15px;
        align-items: center;
    }

    input[type="text"] {
        font-size: 16px !important;
    }
}

@media (max-width: 600px) {
    body {
        padding: 10px;
    }

    .navbar {
        padding: 15px 5%;
    }

    .main-container {
        margin: 15px auto;
        padding: 0 10px;
    }

    .calculator-card {
        padding: 20px 15px;
        border-radius: 16px;
    }

    .tabs {
        justify-content: space-around;
        gap: 10px;
    }

    .tab-btn {
        font-size: 14px;
        padding-bottom: 8px;
    }

    .hero-header h1 {
        font-size: 24px;
        line-height: 1.2;
    }

    .hero-header p {
        font-size: 14px;
        margin-bottom: 20px;
    }

    .result-box {
        padding: 25px 15px;
        min-height: 180px;
    }

    .result-price {
        font-size: 30px;
    }

    input[type="text"] {
        font-size: 16px !important;
    }
}
.install-btn {
    background-color: #166534;
    color: #ffffff;
    border: none;
    padding: 8px 16px;
    font-size: 14px;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: background 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    margin: 10px auto;
}

.install-btn:hover {
    background-color: #14532d;
}