:root {
    --primary: #1877f2;
    --primary-dark: #0d5dbf;
    --success: #00a884;
    --bg: #f0f2f5;
}
* { box-sizing: border-box; }
body {
    background: var(--bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}
main { flex: 1; padding-bottom: 2rem; }

/* ===== NAVBAR — fixed visible colors ===== */
.navbar {
    background: #1877f2 !important;
    padding: 0.55rem 0;
}
.navbar .navbar-brand {
    color: #ffffff !important;
    font-size: 1.2rem;
    font-weight: 700;
}
.navbar .nav-link {
    color: rgba(255,255,255,0.92) !important;
    font-size: 0.95rem;
    font-weight: 500;
}
.navbar .nav-link:hover,
.navbar .nav-link:focus {
    color: #ffffff !important;
    opacity: 1;
}
.navbar .nav-link.text-warning {
    color: #ffc107 !important;
    font-weight: 600;
}
.navbar .badge.bg-success {
    background: #00c853 !important;
    color: #fff !important;
}
.navbar .btn-light {
    background: #fff !important;
    color: #1877f2 !important;
    font-weight: 600;
    border: none;
}
.navbar-toggler {
    border-color: rgba(255,255,255,0.6) !important;
}
.navbar-toggler-icon {
    filter: brightness(0) invert(1);
}

/* Cards */
.card {
    border: none;
    border-radius: 16px;
    box-shadow: 0 2px 12px rgba(0,0,0,.06);
    overflow: hidden;
}
.card-header {
    background: #fff;
    border-bottom: 1px solid #eee;
    font-weight: 600;
    padding: 1rem 1.25rem;
}

/* Hero */
.hero {
    background: linear-gradient(135deg, #1877f2 0%, #0d5dbf 60%, #42b72a 100%);
    color: #fff;
    border-radius: 20px;
    padding: 2.5rem 1.5rem;
    text-align: center;
}
.hero h1 { font-size: 1.75rem; font-weight: 800; margin-bottom: 0.5rem; }
.hero p { opacity: 0.9; font-size: 0.95rem; }

/* Buy Card */
.buy-card {
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 8px 30px rgba(24,119,242,.15);
}
.buy-card .top {
    background: linear-gradient(135deg, #1877f2, #0d5dbf);
    color: #fff;
    padding: 1.75rem 1.5rem;
    text-align: center;
}
.buy-card .top img {
    width: 64px;
    height: 64px;
    border-radius: 14px;
    background: #fff;
    padding: 8px;
    margin-bottom: 0.75rem;
}
.buy-card .price-big {
    font-size: 2.5rem;
    font-weight: 800;
    line-height: 1.1;
}
.buy-card .price-usd { font-size: 0.95rem; opacity: 0.85; }
.buy-card .body { padding: 1.5rem; background: #fff; }

.btn-buy-main {
    background: linear-gradient(135deg, #1877f2, #0d5dbf);
    border: none;
    border-radius: 12px;
    font-size: 1.15rem;
    font-weight: 700;
    padding: 0.9rem 1.5rem;
    width: 100%;
    color: #fff !important;
    transition: transform .15s, box-shadow .15s;
    display: inline-block;
    text-align: center;
    text-decoration: none;
}
.btn-buy-main:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(24,119,242,.35);
    color: #fff !important;
}
.btn-buy-main:disabled { opacity: 0.65; transform: none; }

.balance-bar {
    background: #fff;
    border-radius: 14px;
    padding: 1rem 1.25rem;
    box-shadow: 0 2px 10px rgba(0,0,0,.05);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.otp-box {
    background: #e8f5e9;
    border: 2px dashed #4caf50;
    border-radius: 12px;
    padding: 1rem;
    font-size: 1.6rem;
    font-weight: 700;
    letter-spacing: 3px;
    text-align: center;
    word-break: break-all;
}
.phone-box {
    background: #e7f0ff;
    border-radius: 12px;
    padding: 0.85rem 1rem;
    font-size: 1.2rem;
    font-weight: 600;
    font-family: ui-monospace, monospace;
    word-break: break-all;
}

.form-control, .form-control-lg {
    border-radius: 10px;
    border: 1.5px solid #dde1e6;
}
.form-control:focus {
    border-color: #1877f2;
    box-shadow: 0 0 0 3px rgba(24,119,242,.15);
}
.btn { border-radius: 10px; font-weight: 600; }

@media (max-width: 576px) {
    .table-responsive { font-size: 0.85rem; }
    .hero h1 { font-size: 1.45rem; }
    .buy-card .price-big { font-size: 2.1rem; }
    .navbar-brand { font-size: 1.05rem !important; }
    .balance-bar { flex-direction: column; text-align: center; }
    main.container { padding-left: 12px; padding-right: 12px; }
}

.badge { font-weight: 600; padding: 0.35em 0.65em; }
footer { background: #1a1a2e !important; margin-top: auto; }
footer a { text-decoration: none; }
.feature-card { text-align: center; padding: 1.5rem 1rem; height: 100%; }
.feature-card i { font-size: 2.2rem; margin-bottom: 0.75rem; }