:root {
    --gold-1: #d4af37; /* warm gold */
    --gold-2: #f6d66a; /* lighter gold */
    --accent-2: #00d4ff;
    --card-bg: rgba(11,18,32,0.6);
    --glass: rgba(255,255,255,0.03);
    --muted: #9aa6b2;
    --radius: 12px;
}

/* Enforce a deep black page background while letting your color schemes breathe */
body.scheme-midnight {
    background: #000000 !important;
    color: #f4f6f9;
}

.calculator-wrap {
    max-width: 1100px;
    margin: 48px auto;
    padding: 24px;
}

.card {
    background: linear-gradient(180deg, rgba(255,255,255,0.02), rgba(255,255,255,0.01));
    border-radius: var(--radius);
    padding: 20px;
    color: inherit;
    border: 1px solid rgba(255,255,255,0.03);
    box-shadow: 0 10px 30px rgba(2,6,23,0.5);
}

h1 { font-size: 1.25rem; margin: 0 0 6px 0; }
.lead { color: var(--muted); margin-bottom: 12px; font-size:13px; }

.grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}
.full { grid-column: 1 / -1; }

label { display:block; font-size:13px; color:var(--muted); margin-bottom:6px; }
input[type="number"], select, input[type="text"], input[type="email"] {
    width:100%; padding:10px; border-radius:10px;
    background: #0b0b0b; color:inherit; border:1px solid rgba(255,255,255,0.04);
}

.controls { display:flex; gap:10px; align-items:center; margin-top:12px; }
.btn { padding:10px 14px; border-radius:10px; cursor:pointer; font-weight:700; border:none; }
/* GOLD primary button */
.btn-primary {
    background: linear-gradient(90deg, var(--gold-1), var(--gold-2));
    color: #071214;
    box-shadow: 0 8px 30px rgba(212,175,55,0.15);
}
.btn-ghost { background:transparent; color:var(--muted); border:1px solid rgba(255,255,255,0.04); }

.summary { position:sticky; top:28px; display:flex; flex-direction:column; gap:12px; }

.provider-select { display:flex; gap:8px; align-items:center; flex-wrap:wrap; margin-bottom:10px; }
.provider {
    background: rgba(255,255,255,0.02); padding:8px 10px; border-radius:10px; cursor:pointer; border:1px solid transparent;
    color:var(--muted); font-size:13px;
}
.provider.active { border-color: rgba(212,175,55,0.35); box-shadow: 0 8px 30px rgba(212,175,55,0.06); color:var(--gold-2); }

/* Section navigation styles */
.section-nav {
    display: flex;
    gap: 8px;
    align-items: center;
    margin-bottom: 24px;
    background: rgba(255,255,255,0.02);
    padding: 8px;
    border-radius: 12px;
    border: 1px solid rgba(255,255,255,0.04);
}

.section-btn {
    padding: 12px 20px;
    border-radius: 8px;
    cursor: pointer;
    background: transparent;
    color: var(--muted);
    border: none;
    font-size: 14px;
    font-weight: 600;
    transition: all 0.2s ease;
}

.section-btn.active {
    background: linear-gradient(90deg, var(--gold-1), var(--gold-2));
    color: #071214;
    box-shadow: 0 4px 15px rgba(212,175,55,0.15);
}

.section-content {
    display: none;
}

.section-content.active {
    display: block;
}

.usage-estimation-grid {
    display: grid;
    grid-template-columns: 1fr 380px;
    gap: 20px;
}

@media (max-width:980px) {
    .calculator-wrap { padding: 18px; }
    .usage-estimation-grid { grid-template-columns: 1fr; }
    .summary { position:static; }
}