/* css/style.css */
:root {
    --primary: #10b981;
    --secondary: #3b82f6;
    --accent: #f59e0b;
    --bg: #ffffff;
    --card-bg: #f0fdf4;
    --text: #1e293b;
    --shadow: 0 20px 40px -15px rgba(16,185,129,0.15);
    --border-radius-card: 24px;
    --border-radius-btn: 16px;
    --font-size-base: clamp(1rem, 2.5vw, 1.125rem);
}

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

body {
    font-family: system-ui, -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    font-size: var(--font-size-base);
    line-height: 1.6;
    padding: 1rem;
}

header {
    background: var(--bg);
    box-shadow: var(--shadow);
}

.nav {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav h1 {
    font-size: clamp(1.5rem, 4vw, 2rem);
    color: var(--primary);
}

.nav ul {
    display: flex;
    list-style: none;
    gap: 1rem;
}

.nav a {
    text-decoration: none;
    color: var(--text);
    font-size: clamp(0.875rem, 2vw, 1rem);
}

.hero {
    text-align: center;
    padding: 2rem 0;
    max-width: 1200px;
    margin: 0 auto;
}

.hero h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    color: var(--primary);
    margin-bottom: 1rem;
}

.calculators-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    max-width: 1200px;
    margin: 2rem auto;
}

.card {
    background: var(--card-bg);
    border-radius: var(--border-radius-card);
    padding: 1.5rem;
    text-align: center;
    text-decoration: none;
    color: var(--text);
    box-shadow: var(--shadow);
    transition: transform 0.2s;
    min-height: 120px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.card:hover {
    transform: translateY(-4px);
}

.card i {
    font-size: clamp(2rem, 6vw, 3rem);
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.card h2 {
    font-size: clamp(1.25rem, 3vw, 1.5rem);
    margin-bottom: 0.5rem;
}

#about {
    text-align: center;
    padding: 2rem 0;
    max-width: 1200px;
    margin: 0 auto;
}

footer {
    text-align: center;
    padding: 2rem 0;
    background: var(--card-bg);
    margin-top: 2rem;
}

footer button {
    background: var(--primary);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius-btn);
    font-size: 1rem;
    cursor: pointer;
    min-height: 48px;
    min-width: 200px;
}

/* Calculator Pages */
.calculator-hero {
    text-align: center;
    padding: 2rem 0;
}

.calculator-hero h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    color: var(--primary);
}

.form-section {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: var(--border-radius-card);
    box-shadow: var(--shadow);
    max-width: 600px;
    margin: 2rem auto;
}

.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: bold;
}

input, select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #d1d5db;
    border-radius: 8px;
    font-size: 1rem;
}

.toggle {
    display: flex;
    gap: 1rem;
    margin-top: 0.5rem;
}

.toggle input[type="radio"] {
    width: auto;
}

.results {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: var(--border-radius-card);
    box-shadow: var(--shadow);
    margin: 2rem auto;
    max-width: 600px;
    text-align: center;
}

.results h2 {
    color: var(--primary);
}

.copy-btn {
    background: var(--secondary);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius-btn);
    cursor: pointer;
    margin-top: 1rem;
    min-height: 48px;
}

.content-section {
    max-width: 800px;
    margin: 2rem auto;
    padding: 1rem;
}

.content-section h2 {
    color: var(--primary);
    margin-bottom: 1rem;
}

.faq {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: var(--border-radius-card);
    margin-bottom: 1rem;
}

.faq h3 {
    color: var(--secondary);
}

.related {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
}

.related a {
    background: var(--card-bg);
    padding: 1rem;
    border-radius: var(--border-radius-card);
    text-decoration: none;
    color: var(--text);
}

.chart {
    width: 100%;
    height: 200px;
    background: #f3f4f6;
    border-radius: 8px;
    margin: 1rem 0;
}

/* Responsive */
@media (min-width: 480px) {
    .calculators-grid {
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    }
}

@media (min-width: 768px) {
    body {
        padding: 2rem;
    }
    .nav-container {
        padding: 0 2rem;
    }
    .form-section, .results {
        padding: 3rem;
    }
}

@media (min-width: 1024px) {
    .calculators-grid {
        gap: 2rem;
    }
}

@media (min-width: 1440px) {
    .nav-container {
        max-width: 1200px;
        margin: 0 auto;
    }
}

/* Touch-friendly */
button, input[type="submit"] {
    min-height: 48px;
    min-width: 48px;
}