:root {
    --primary: #059669;
    --primary-hover: #047857;
    --dark: #111827;
    --gray-bg: #f9fafb;
    --text-main: #1f2937;
    --border: #e5e7eb;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--gray-bg);
    color: var(--text-main);
    margin: 0;
    line-height: 1.6;
}

/* Navbar */
.navbar-global {
    background: var(--dark);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}
.nav-container {
    max-width: 1000px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
}
.nav-logo {
    color: white;
    font-weight: 800;
    text-decoration: none;
    font-size: 1.2rem;
}
.nav-links {
    list-style: none;
    display: flex;
    gap: 20px;
    margin: 0;
}
.nav-links a {
    color: #9ca3af;
    text-decoration: none;
    font-size: 0.85rem;
    font-weight: 600;
}
.nav-links a.active { color: white; border-bottom: 2px solid var(--primary); }

/* Layout */
.container { max-width: 850px; margin: 40px auto; padding: 0 20px; }
.card { background: white; padding: 30px; border-radius: 12px; border: 1px solid var(--border); box-shadow: 0 4px 6px rgba(0,0,0,0.05); margin-bottom: 25px; }
.grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.sub-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; grid-column: span 2; }

/* Form */
.input-group label { display: block; font-size: 0.8rem; font-weight: 700; margin-bottom: 8px; color: #4b5563; }
input, select { width: 100%; padding: 12px; border: 1px solid var(--border); border-radius: 8px; font-size: 1rem; box-sizing: border-box; }
.btn-main { width: 100%; background: var(--primary); color: white; border: none; padding: 16px; border-radius: 8px; font-weight: 700; cursor: pointer; margin-top: 20px; }
.btn-main:hover { background: var(--primary-hover); }

/* Results */
.grid-res { display: grid; grid-template-columns: 1fr 1fr; gap: 15px; }
.res-card { background: #f0fdf4; padding: 20px; border-radius: 10px; text-align: center; }
.big-val { font-size: 1.8rem; font-weight: 800; color: var(--primary); }

footer a { color: #6b7280; text-decoration: none; margin: 0 10px; }

@media (max-width: 600px) {
    .grid, .sub-grid, .grid-res { grid-template-columns: 1fr; }
    .nav-container { flex-direction: column; gap: 10px; }
}