body {
    background: #f8f9fa;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

main {
    flex: 1 0 auto;
}

.navbar-brand {
    font-weight: 900;
    letter-spacing: -1px;
}

.main-card {
    border: none;
    border-radius: 1.25rem;
    box-shadow: 0 1rem 3rem rgba(0, 0, 0, 0.08);
}

/* Ensure rounded card does not clip control borders at the inner edge */
.main-card .card-body {
    overflow: visible;
}

.ad-slot {
    background: #eaeff2;
    border: 2px dashed #ced4da;
    min-height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #adb5bd;
    border-radius: 1rem;
    font-size: 0.8rem;
}

footer {
    background: #fff;
    padding: 2rem 0;
    border-top: 1px solid #dee2e6;
    margin-top: auto;
}

.reveal-input-group {
    max-width: 450px;
}

.reveal-box {
    font-family: "Courier New", monospace;
    font-size: 1.5rem;
    letter-spacing: 1px;
}

.input-group-text {
    cursor: pointer;
    background: #fff;
    border-left: none;
}

/* Avoid flex columns clipping full-width controls at column edges */
form .row > [class*="col-"] {
    min-width: 0;
}