:root {
    --bg-dark: #0f172a;
    --card-dark: #1e293b;
    --accent: #38bdf8;
    --success: #22c55e;
    --danger: #ef4444;
    --text-white: #f8fafc;
}

body {
    margin: 0;
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-white);
}

.dashboard {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: 250px;
    background: #020617;
    padding: 2rem;
    border-right: 1px solid #334155;
}

.nav-btn {
    display: block;
    width: 100%;
    padding: 1rem;
    background: none;
    border: none;
    color: #94a3b8;
    text-align: left;
    cursor: pointer;
    border-radius: 8px;
    margin-bottom: 0.5rem;
}

.nav-btn.active {
    background: var(--card-dark);
    color: var(--accent);
}

.content {
    flex: 1;
    padding: 3rem;
}

.calc-card {
    background: var(--card-dark);
    padding: 2rem;
    border-radius: 12px;
    max-width: 500px;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
}

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

label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
    color: #94a3b8;
}

input, select {
    width: 100%;
    padding: 0.75rem;
    background: #0f172a;
    border: 1px solid #334155;
    color: white;
    border-radius: 6px;
}

.calc-btn {
    width: 100%;
    padding: 1rem;
    background: var(--accent);
    border: none;
    border-radius: 6px;
    font-weight: bold;
    cursor: pointer;
    transition: transform 0.2s;
}

.calc-btn:hover { transform: translateY(-2px); }

.results {
    margin-top: 2rem;
    padding: 1rem;
    border-top: 1px solid #334155;
}

.hidden { display: none; }