:root {
    --primary-blue: #0052cc;
    --hero-gradient: linear-gradient(135deg, #0061ff 0%, #0033aa 100%);
    --bg-light: #f8fafc;
    --white: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius: 12px;
    --transition: all 0.3s ease;
    --success-bg: #ecfdf5;
    --success-text: #047857;
    --warning-bg: #fff7ed;
    --warning-text: #c2410c;
    --danger-bg: #fef2f2;
    --danger-text: #b91c1c;
}

body {
    margin: 0;
    font-family: 'Inter', sans-serif;
    color: var(--text-main);
    background: var(--white);
    line-height: 1.7;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 16px;
}

.section-padding {
    padding: 64px 0;
}

.section-spacing {
    margin-top: 32px;
}

.bg-light {
    background: var(--bg-light);
}

.hidden {
    display: none !important;
}

/* HERO */

.hero {
    background: var(--hero-gradient);
    color: var(--white);
    padding: 30px 0 70px;
}

.hero h1 {
    font-size: clamp(2rem, 4vw, 3rem);
    margin-bottom: 12px;
}

.hero-lead {
    font-size: 1.05rem;
    opacity: 0.95;
}

.hero-summary {
    opacity: 0.9;
    margin-bottom: 20px;
}

.breadcrumb {
    font-size: 0.9rem;
    margin-bottom: 20px;
}

.breadcrumb a {
    color: rgba(255,255,255,0.9);
}

.hero-actions {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

/* BUTTONS */

.btn {
    padding: 12px 18px;
    border-radius: var(--radius);
    border: none;
    cursor: pointer;
    font-weight: 600;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.btn-primary {
    background: var(--white);
    color: var(--primary-blue);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: transparent;
    border: 1px solid rgba(255,255,255,0.4);
    color: var(--white);
}

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

/* CARDS */

.section-card,
.calculator-card {
    background: var(--white);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 28px;
    box-shadow: var(--shadow-sm);
}

.section-card h2 {
    margin-bottom: 12px;
}

/* CALCULATOR LAYOUT */

.calculator-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.card-heading {
    display: flex;
    gap: 14px;
    margin-bottom: 20px;
}

.card-icon {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    background: rgba(0,82,204,0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
}

/* MODE SWITCH */

.mode-switch {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-bottom: 20px;
}

.mode-option {
    border: 1px solid var(--border-color);
    padding: 14px;
    border-radius: 10px;
    cursor: pointer;
}

.mode-option.active {
    border-color: var(--primary-blue);
    background: #f0f6ff;
}

/* FORM */

.form-grid {
    display: grid;
    gap: 16px;
}

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

.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.form-group input,
.form-group select {
    padding: 12px;
    border-radius: 10px;
    border: 1px solid var(--border-color);
}

.check-row {
    margin-top: 14px;
    display: flex;
    gap: 10px;
}

/* RESULTS */

.results-placeholder {
    text-align: center;
    padding: 40px;
}

.results-top h3 {
    font-size: 2rem;
    color: var(--primary-blue);
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}

.result-tile {
    border: 1px solid var(--border-color);
    padding: 14px;
    border-radius: 10px;
}

.highlight-tile {
    background: #f8fbff;
}

/* TABLES */

.table-wrap {
    overflow-x: auto;
}

.info-table {
    width: 100%;
    border-collapse: collapse;
}

.info-table th,
.info-table td {
    border: 1px solid var(--border-color);
    padding: 12px;
}

/* MINI CARDS */

.mini-cards {
    display: grid;
    gap: 16px;
    margin-top: 16px;
}

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

.mini-cards.four {
    grid-template-columns: repeat(4, 1fr);
}

.mini-card {
    border: 1px solid var(--border-color);
    padding: 16px;
    border-radius: 10px;
    background: var(--bg-light);
}

/* COMPARISON */

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

.comparison-card {
    border: 1px solid var(--border-color);
    padding: 16px;
    border-radius: 10px;
}

.emphasis-card {
    background: #f0f6ff;
}

/* WARNINGS */

.warning-list {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.warning-item {
    border: 1px solid var(--border-color);
    padding: 16px;
    border-radius: 10px;
}

/* FAQ */

.faq-list {
    display: grid;
    gap: 12px;
}

.faq-item summary {
    cursor: pointer;
    font-weight: 600;
    padding: 14px;
}

/* RELATED */

.related-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
}

.related-card {
    border: 1px solid var(--border-color);
    padding: 16px;
    border-radius: 10px;
    display: block;
}

/* CTA */

.cta-card {
    text-align: center;
    background: var(--primary-blue);
    color: var(--white);
    padding: 32px;
    border-radius: 12px;
}

.cta-actions {
    margin-top: 20px;
    display: flex;
    gap: 12px;
    justify-content: center;
}

/* RESPONSIVE */

@media (max-width: 900px) {
    .calculator-layout {
        grid-template-columns: 1fr;
    }

    .form-grid.two-col {
        grid-template-columns: 1fr;
    }

    .results-grid {
        grid-template-columns: 1fr;
    }

    .mini-cards.three,
    .mini-cards.four,
    .comparison-grid,
    .warning-list,
    .related-grid {
        grid-template-columns: 1fr;
    }
}