body {
    background: #f1f3f5;
    font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
}

.calculator-card {
    width: 480px;
    border-radius: 0px;
    border: 1px solid #e5e7eb;
}

h4 {
    font-weight: 600;
}

.form-control,
.form-select {
    border-radius: 0px;
}

button {
    border-radius: 0px;
    font-weight: 500;
}

#result {
    border-radius: 0px;
}

/* Navbar base */
.custom-navbar {
    background: #ffffff;
    border-bottom: 1px solid #e5e7eb;
    z-index: 1000;
}

/* LEGO placeholder */
.lego-logo {
    font-weight: 800;
    letter-spacing: 2px;
    color: #163e81;
}

/* Nav buttons */
.nav-btn {
    background: #163e81;
    color: #fff !important;
    border-radius: 0px;
    padding: 6px 16px 9px 16px;
    font-weight: normal;
    transition: 0.2s ease;
    text-align: center;
    font-size: 13px;
}

.nav-btn:hover {
    background: #f2f2f2;
    color: #000 !important;
}

/* Current / Active state */
.nav-btn.current,
.nav-btn.active {
    background: #f2f2f2;
    color: #000 !important;
    font-weight: 600;
}

/* Mobile spacing */
@media (max-width: 991px) {
    .navbar-nav {
        margin-top: 10px;
    }

    .nav-btn {
        width: 100%;
    }
}