:root {
    --bg: #ffffff;
    --text: #1a1a1a;
    --accent: #2563eb;
    --card-bg: #f9fafb;
    --border: #e5e7eb;
    --input-bg: #ffffff;
}

[data-theme="dark"] {
    --bg: #121212;
    --text: #f3f4f6;
    --accent: #60a5fa;
    --card-bg: #1e1e1e;
    --border: #374151;
    --input-bg: #2d2d2d;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.6;
    margin: 0;
    padding: 0;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3rem;
    border-bottom: 1px solid var(--border);
    padding-bottom: 1rem;
}

h1 { font-weight: 700; font-size: 1.5rem; margin: 0; letter-spacing: -0.025em; }

.theme-toggle {
    background: none;
    border: 1px solid var(--border);
    color: var(--text);
    padding: 0.5rem 1rem;
    cursor: pointer;
    border-radius: 6px;
    font-size: 0.8rem;
}

section {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 2rem;
    border: 1px solid var(--border);
}

h2 { font-size: 1.1rem; margin-top: 0; margin-bottom: 1.5rem; color: var(--accent); }

.item-row {
    display: flex;
    flex-direction: column;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border);
}

.item-row:last-child { border-bottom: none; }

.row-header {
    display: flex;
    align-items: center;
}

.row-header input[type="checkbox"] {
    width: 18px;
    height: 18px;
    margin-right: 1rem;
}

.item-label { flex-grow: 1; font-size: 0.95rem; font-weight: 500; }

.gender-inputs {
    display: none;
    gap: 1rem;
    margin-top: 0.75rem;
    margin-left: 2.2rem;
}

.gender-inputs input[type="number"] {
    background: var(--input-bg);
    border: 1px solid var(--border);
    color: var(--text);
    padding: 0.5rem;
    border-radius: 4px;
    width: 100px;
}

.qty-input {
    width: 80px !important;
    visibility: hidden;
    background: var(--input-bg);
    border: 1px solid var(--border);
    color: var(--text);
    padding: 0.5rem;
    border-radius: 4px;
}

.calculate-btn {
    background: var(--accent);
    color: white;
    border: none;
    width: 100%;
    padding: 1rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    margin-top: 1rem;
    transition: opacity 0.2s;
}

.calculate-btn:hover { opacity: 0.9; }

#results {
    display: none;
    margin-top: 2rem;
    border-top: 2px solid var(--accent);
    padding-top: 2rem;
}

.result-card {
    background: var(--card-bg);
    border-left: 4px solid var(--accent);
    padding: 1rem;
    margin-bottom: 1rem;
}

.result-group-title {
    font-weight: 600;
    margin-bottom: 0.5rem;
    text-transform: capitalize;
}

footer {
    text-align: center;
    margin-top: 4rem;
    padding: 2rem 0;
    font-size: 0.8rem;
    opacity: 0.7;
}

footer a { color: var(--text); text-decoration: underline; }