:root {
    --bt-ink: #0f172a;
    --bt-muted: #64748b;
    --bt-line: #dbe7f3;
    --bt-blue: #2563eb;
    --bt-blue-dark: #1d4ed8;
    --bt-green: #059669;
    --bt-card-shadow: 0 18px 45px rgba(15, 23, 42, .07);
}

.bt-brand-page {
    color: var(--bt-ink);
    background:
        radial-gradient(circle at top left, rgba(37, 99, 235, .12), transparent 30rem),
        linear-gradient(135deg, #f8fafc 0%, #eef6ff 48%, #ffffff 100%);
}

.bt-nav {
    background: rgba(255, 255, 255, .86);
    border-bottom: 1px solid var(--bt-line);
    backdrop-filter: blur(18px);
}

.bt-card {
    background: rgba(255, 255, 255, .94);
    border: 1px solid var(--bt-line);
    box-shadow: var(--bt-card-shadow);
}

.bt-soft-card {
    background: linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);
    border: 1px solid var(--bt-line);
    box-shadow: 0 10px 26px rgba(15, 23, 42, .045);
}

.bt-input {
    border-color: #dbe3ef !important;
    background: #f8fafc !important;
}

.bt-input:focus {
    border-color: var(--bt-blue) !important;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, .14) !important;
    outline: none !important;
}

.bt-primary {
    background: var(--bt-blue) !important;
    box-shadow: 0 12px 22px rgba(37, 99, 235, .18);
}

.bt-primary:hover {
    background: var(--bt-blue-dark) !important;
}

.bt-success {
    background: var(--bt-green) !important;
    box-shadow: 0 12px 22px rgba(5, 150, 105, .16);
}

.bt-logo {
    background: #ffffff;
    border: 1px solid var(--bt-line);
    object-fit: contain;
}

.bt-section-title {
    color: var(--bt-ink);
    letter-spacing: 0;
}

.bt-dialog-backdrop {
    position: fixed;
    inset: 0;
    z-index: 9999;
    display: none;
    align-items: center;
    justify-content: center;
    padding: 1rem;
    background: rgba(15, 23, 42, .42);
    backdrop-filter: blur(8px);
}

.bt-dialog-backdrop.is-open {
    display: flex;
}

.bt-dialog-panel {
    width: min(100%, 28rem);
    border-radius: 1rem;
    border: 1px solid var(--bt-line);
    background: #ffffff;
    box-shadow: 0 24px 70px rgba(15, 23, 42, .2);
    padding: 1.5rem;
}

.bt-dialog-icon {
    width: 2.75rem;
    height: 2.75rem;
    border-radius: 999px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: .9rem;
    background: #eff6ff;
    color: var(--bt-blue);
    font-weight: 800;
}

.bt-dialog-title {
    margin: 0;
    color: var(--bt-ink);
    font-size: 1.125rem;
    font-weight: 700;
}

.bt-dialog-message {
    margin: .5rem 0 0;
    color: var(--bt-muted);
    line-height: 1.55;
    font-size: .92rem;
}

.bt-dialog-actions {
    display: flex;
    justify-content: flex-end;
    gap: .65rem;
    margin-top: 1.35rem;
}

.bt-dialog-btn {
    border: 0;
    border-radius: .75rem;
    padding: .7rem 1rem;
    font-size: .875rem;
    font-weight: 700;
    cursor: pointer;
}

.bt-dialog-btn-primary {
    background: var(--bt-blue);
    color: #ffffff;
}

.bt-dialog-btn-primary:hover {
    background: var(--bt-blue-dark);
}

.bt-dialog-btn-secondary {
    background: #f1f5f9;
    color: #334155;
}

.bt-dialog-btn-secondary:hover {
    background: #e2e8f0;
}

.bt-account-menu {
    position: relative;
}

.bt-account-menu-panel {
    position: absolute;
    right: 0;
    top: calc(100% + .5rem);
    z-index: 50;
    width: 11rem;
    transform-origin: top right;
    transform: translateY(-.25rem) scale(.98);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity .14s ease, transform .14s ease, visibility .14s ease;
}

.bt-account-menu.is-open .bt-account-menu-panel {
    transform: translateY(0) scale(1);
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
}

.bt-account-menu-button[aria-expanded="true"] {
    background: #eff6ff;
}