:root {
    --bg-color: #F5F5F7;
    --card-bg: #FFFFFF;
    --text-primary: #1D1D1F;
    --text-secondary: #86868B;
    --accent-blue: #0071E3;
    --accent-blue-hover: #0077ED;
    --border-radius: 18px;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.04);
    --input-bg: #F5F5F7;
    --switch-bg: #E3E3E8;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid rgba(0,0,0,0.05);
    padding: 1rem 0;
}

.nav-container {
    max-width: 980px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-weight: 600;
    font-size: 1.2rem;
    color: var(--text-primary);
    text-decoration: none;
}

main {
    flex: 1;
    padding: 40px 20px;
    max-width: 800px;
    margin: 0 auto;
    width: 100%;
}

h1 {
    font-size: 2.5rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: 10px;
    letter-spacing: -0.02em;
}

.subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 40px;
    font-size: 1.1rem;
}

.calculator-card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: 40px;
    transition: transform 0.3s ease;
}

.mode-switch-container {
    display: flex;
    justify-content: center;
    margin-bottom: 30px;
}

.mode-switch {
    background-color: var(--switch-bg);
    padding: 4px;
    border-radius: 10px;
    display: inline-flex;
    width: 100%;
    max-width: 400px;
}

.mode-btn {
    flex: 1;
    border: none;
    background: transparent;
    padding: 10px;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s ease;
}

.mode-btn.active {
    background-color: white;
    color: var(--text-primary);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    font-weight: 600;
}

label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

select {
    width: 100%;
    padding: 16px;
    font-size: 1rem;
    border: 1px solid transparent;
    background-color: var(--input-bg);
    border-radius: 12px;
    color: var(--text-primary);
    appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%2386868B' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 1rem center;
    background-size: 1.2em;
    cursor: pointer;
    transition: all 0.2s;
}

select:focus, input:focus {
    outline: none;
    background-color: #fff;
    box-shadow: 0 0 0 4px rgba(0, 113, 227, 0.15);
    border: 1px solid var(--accent-blue);
}

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

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

input[type="number"] {
    width: 100%;
    padding: 16px;
    font-size: 1rem;
    border: 1px solid transparent;
    background-color: var(--input-bg);
    border-radius: 12px;
    color: var(--text-primary);
    transition: all 0.2s;
}

.hint {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 6px;
}

.toggle-container {
    text-align: center;
    margin-bottom: 10px;
}

.toggle-link {
    font-size: 0.9rem;
    color: var(--accent-blue);
    text-decoration: none;
    font-weight: 500;
}

.toggle-link:hover {
    text-decoration: underline;
}

.result-section {
    background: #F5F9FF;
    border-radius: 14px;
    padding: 30px;
    text-align: center;
    margin-top: 20px;
    border: 1px solid rgba(0, 113, 227, 0.1);
}

.result-title {
    color: var(--accent-blue);
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 10px;
}

.result-value {
    font-size: 3rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.03em;
}

.result-subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
}

.disclaimer {
    text-align: center;
    font-size: 0.8rem;
    color: #C1C1C4;
    margin-top: 40px;
    padding-bottom: 40px;
}

.breakdown-container {
    padding: 0 10px;
    text-align: left;
    font-size: 0.9rem;
    color: #86868B;
    margin-top: 20px;
}

.row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 6px;
}

.uitleg-section {
    margin-top: 48px;
}

.uitleg-section h2 {
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 14px;
    letter-spacing: -0.01em;
}

.uitleg-section h3 {
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 24px 0 14px;
}

.uitleg-section p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 12px;
}

.uitleg-hint {
    font-size: 0.85rem !important;
    color: #B0B0B5 !important;
    margin-top: 16px !important;
    text-align: center;
}

.voorbeeld-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 14px;
    margin: 0 0 6px;
}

.voorbeeld-card {
    background: var(--card-bg);
    border-radius: 14px;
    padding: 18px 14px;
    text-align: center;
    box-shadow: var(--shadow);
    border: 1px solid rgba(0,0,0,0.04);
}

.voorbeeld-bruto {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.voorbeeld-netto {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--accent-blue);
    letter-spacing: -0.02em;
}

.voorbeeld-hint {
    font-size: 0.75rem;
    color: #C1C1C4;
    margin-top: 4px;
}

.faq-section {
    margin-top: 48px;
}

.faq-section h2 {
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 16px;
    letter-spacing: -0.01em;
}

.faq-section details {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 16px 20px;
    margin-bottom: 10px;
    box-shadow: var(--shadow);
    cursor: pointer;
}

.faq-section summary {
    font-weight: 600;
    font-size: 0.95rem;
    color: var(--text-primary);
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.faq-section summary::-webkit-details-marker { display: none; }

.faq-section summary::after {
    content: '+';
    font-size: 1.2rem;
    color: var(--accent-blue);
    font-weight: 400;
    flex-shrink: 0;
    margin-left: 12px;
}

.faq-section details[open] summary::after { content: '−'; }

.faq-section details p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-top: 12px;
    line-height: 1.65;
}

@media (max-width: 600px) {
    h1 { font-size: 2rem; }
    .input-grid { grid-template-columns: 1fr; }
    .calculator-card { padding: 25px; }
    .result-value { font-size: 2.5rem; }
    .voorbeeld-grid { grid-template-columns: 1fr; }
}