/* ============================================
   Ч/Б стиль — чёрные прямоугольные рамки
   ============================================ */

:root {
    --bw-black: #000000;
    --bw-white: #ffffff;
    --bw-gray-light: #f5f5f5;
    --bw-gray-mid: #e0e0e0;
    --bw-gray-dark: #555555;
    --bw-border: 2px solid #000000;
    --bw-border-thin: 1px solid #000000;
}

/* === Базовые === */
body {
    background: var(--bw-white);
    color: var(--bw-black);
    font-family: 'Segoe UI', system-ui, sans-serif;
}

/* === Навбар === */
.navbar {
    background: var(--bw-white) !important;
    border-bottom: 2px solid var(--bw-black);
    border-radius: 0 !important;
}

.navbar-brand {
    font-weight: 700;
    color: var(--bw-black) !important;
    letter-spacing: 0.03em;
}

.navbar-brand:hover {
    color: var(--bw-gray-dark) !important;
}

.nav-link {
    color: var(--bw-black) !important;
    font-weight: 500;
}

/* === Вкладки входа/регистрации === */
.nav-tabs .auth-tab {
    color: #000 !important;
    background: #fff !important;
    background-color: #fff !important;
    border: 1px solid #000 !important;
    border-radius: 0 !important;
    border-bottom-color: #000 !important;
    font-weight: 700 !important;
}

.nav-tabs .auth-tab.active {
    color: #fff !important;
    background: #000 !important;
    background-color: #000 !important;
}

.nav-link:hover,
.nav-link:focus {
    color: var(--bw-gray-dark) !important;
}

.nav-tabs .auth-tab:hover,
.nav-tabs .auth-tab:focus {
    color: #000 !important;
    border-color: #000 !important;
}

.nav-tabs .auth-tab.active:hover,
.nav-tabs .auth-tab.active:focus {
    color: #fff !important;
    background: #000 !important;
    background-color: #000 !important;
}

.navbar-toggler {
    border: 2px solid var(--bw-black) !important;
    border-radius: 0 !important;
}

/* === Дропдаун === */
.dropdown-menu {
    background: var(--bw-white);
    border: var(--bw-border);
    border-radius: 0 !important;
    box-shadow: 4px 4px 0 var(--bw-black);
    padding: 0;
}

.dropdown-item {
    color: var(--bw-black);
    border-radius: 0 !important;
    padding: 0.5rem 1rem;
}

.dropdown-item:hover {
    background: var(--bw-black);
    color: var(--bw-white);
}

.dropdown-divider {
    border-color: var(--bw-black);
    margin: 0;
}

/* === Карточки === */
.card {
    background: var(--bw-white);
    border: var(--bw-border) !important;
    border-radius: 0 !important;
    box-shadow: 4px 4px 0 var(--bw-black);
    transition: box-shadow 0.15s, transform 0.15s;
}

.card:hover {
    box-shadow: 6px 6px 0 var(--bw-black);
}

.card-header {
    background: var(--bw-black) !important;
    color: var(--bw-white) !important;
    border-bottom: var(--bw-border) !important;
    border-radius: 0 !important;
    font-weight: 600;
}

.card-header * {
    color: var(--bw-white) !important;
}

.card-body {
    background: var(--bw-white);
}

.card-title {
    color: var(--bw-black);
    font-weight: 700;
}

.card-footer {
    background: var(--bw-gray-light);
    border-top: var(--bw-border-thin) !important;
    border-radius: 0 !important;
}

.test-card:hover {
    transform: translateY(-3px);
}

/* === Кнопки === */
.btn {
    border-radius: 0 !important;
    font-weight: 600;
    transition: all 0.15s;
}

.btn-primary {
    background: var(--bw-black) !important;
    border: var(--bw-border) !important;
    color: var(--bw-white) !important;
    box-shadow: 3px 3px 0 #555;
}

.btn-primary:hover,
.btn-primary:focus {
    background: var(--bw-white) !important;
    color: var(--bw-black) !important;
    box-shadow: 3px 3px 0 #555;
}

.btn-secondary {
    background: var(--bw-white) !important;
    border: var(--bw-border) !important;
    color: var(--bw-black) !important;
    box-shadow: 3px 3px 0 #999;
}

.btn-secondary:hover {
    background: var(--bw-gray-light) !important;
    box-shadow: 3px 3px 0 #999;
}

.btn-success {
    background: var(--bw-black) !important;
    border: var(--bw-border) !important;
    color: var(--bw-white) !important;
    box-shadow: 3px 3px 0 #555;
}

.btn-success:hover {
    background: var(--bw-white) !important;
    color: var(--bw-black) !important;
}

.btn-danger {
    background: var(--bw-white) !important;
    border: var(--bw-border) !important;
    color: var(--bw-black) !important;
    box-shadow: 3px 3px 0 #999;
}

.btn-danger:hover {
    background: var(--bw-black) !important;
    color: var(--bw-white) !important;
}

.btn-outline-primary,
.btn-outline-secondary,
.btn-outline-success,
.btn-outline-danger,
.btn-outline-info,
.btn-outline-warning {
    background: var(--bw-white) !important;
    border: var(--bw-border) !important;
    color: var(--bw-black) !important;
    box-shadow: 2px 2px 0 #999;
}

.btn-outline-primary:hover,
.btn-outline-secondary:hover,
.btn-outline-success:hover,
.btn-outline-danger:hover,
.btn-outline-info:hover,
.btn-outline-warning:hover {
    background: var(--bw-black) !important;
    color: var(--bw-white) !important;
    box-shadow: 2px 2px 0 #555;
}

.btn-sm {
    box-shadow: 2px 2px 0 #999;
}

/* Активная кнопка (например, текущее задание) */
.btn-primary.active,
.btn-primary:active {
    background: var(--bw-white) !important;
    color: var(--bw-black) !important;
    transform: translate(2px, 2px);
    box-shadow: 1px 1px 0 #555 !important;
}

/* === Алерты === */
.alert {
    border: var(--bw-border) !important;
    border-radius: 0 !important;
    box-shadow: 3px 3px 0 var(--bw-black);
    color: var(--bw-black) !important;
}

.alert-primary,
.alert-info {
    background: var(--bw-gray-light) !important;
    border-left: 4px solid var(--bw-black) !important;
}

.alert-success {
    background: var(--bw-white) !important;
    border-left: 4px solid var(--bw-black) !important;
}

.alert-warning {
    background: var(--bw-gray-light) !important;
    border-left: 4px solid var(--bw-black) !important;
}

.alert-danger {
    background: var(--bw-white) !important;
    border-left: 4px solid var(--bw-black) !important;
    font-weight: 600;
}

/* === Бейджи === */
.badge {
    border-radius: 0 !important;
    border: var(--bw-border-thin);
    font-weight: 600;
}

.badge.bg-primary,
.badge.bg-success,
.badge.bg-info,
.badge.bg-warning {
    background: var(--bw-black) !important;
    color: var(--bw-white) !important;
    border-color: var(--bw-black);
}

.badge.bg-secondary,
.badge.bg-light {
    background: var(--bw-white) !important;
    color: var(--bw-black) !important;
    border-color: var(--bw-black);
}

/* === Таблицы === */
.table {
    border: var(--bw-border);
    color: var(--bw-black);
}

.table th {
    background: var(--bw-black) !important;
    color: var(--bw-white) !important;
    border-color: var(--bw-black) !important;
    font-weight: 700;
}

.table td {
    border-color: var(--bw-gray-mid) !important;
}

.table-hover tbody tr:hover {
    background: var(--bw-gray-light) !important;
    color: var(--bw-black);
}

.table-striped tbody tr:nth-of-type(odd) {
    background: var(--bw-gray-light);
}

/* === Формы === */
.form-control,
.form-select {
    border: var(--bw-border) !important;
    border-radius: 0 !important;
    background: var(--bw-white);
    color: var(--bw-black);
    box-shadow: none !important;
}

.form-control:focus,
.form-select:focus {
    border-color: var(--bw-black) !important;
    box-shadow: 3px 3px 0 var(--bw-black) !important;
    outline: none;
}

.form-check-input {
    border: var(--bw-border) !important;
    border-radius: 0 !important;
}

.form-check-input:checked {
    background-color: var(--bw-black) !important;
    border-color: var(--bw-black) !important;
}

.form-label {
    font-weight: 600;
    color: var(--bw-black);
}

/* === Прогресс-бар === */
.progress {
    background: var(--bw-gray-mid);
    border: var(--bw-border-thin);
    border-radius: 0 !important;
    height: 1rem;
}

.progress-bar {
    background: var(--bw-black) !important;
    border-radius: 0 !important;
}

/* === Модальные окна === */
.modal-content {
    border: var(--bw-border) !important;
    border-radius: 0 !important;
    box-shadow: 6px 6px 0 var(--bw-black);
}

.modal-header {
    background: var(--bw-black);
    color: var(--bw-white);
    border-bottom: var(--bw-border) !important;
    border-radius: 0 !important;
}

.modal-header .modal-title { color: var(--bw-white); }
.modal-header .btn-close { filter: invert(1); }

.modal-footer {
    border-top: var(--bw-border) !important;
    border-radius: 0 !important;
}

/* === Пагинация === */
.pagination .page-link {
    border: var(--bw-border-thin) !important;
    border-radius: 0 !important;
    color: var(--bw-black);
    background: var(--bw-white);
}

.pagination .page-item.active .page-link {
    background: var(--bw-black) !important;
    border-color: var(--bw-black) !important;
    color: var(--bw-white) !important;
}

.pagination .page-link:hover {
    background: var(--bw-black) !important;
    color: var(--bw-white) !important;
}

/* === Спиннер === */
.spinner-border {
    color: var(--bw-black) !important;
}

/* === Ссылки === */
a {
    color: var(--bw-black);
    text-decoration: underline;
}

a:hover {
    color: var(--bw-gray-dark);
}

.nav-link { text-decoration: none; }
.btn { text-decoration: none; }
.dropdown-item { text-decoration: none; }

/* === Заголовки страниц === */
h1, h2, h3, h4, h5, h6 {
    color: var(--bw-black);
    font-weight: 700;
}

/* === Утилиты — цветной текст сводим к ч/б === */
.text-primary   { color: var(--bw-black) !important; }
.text-success   { color: var(--bw-black) !important; }
.text-info      { color: var(--bw-gray-dark) !important; }
.text-warning   { color: var(--bw-black) !important; }
.text-danger    { color: var(--bw-black) !important; font-weight: 700; }
.text-muted     { color: var(--bw-gray-dark) !important; }

/* === Результаты === */
.result-correct {
    color: var(--bw-black);
    font-weight: 700;
}

.result-incorrect {
    color: var(--bw-black);
    font-weight: 400;
    opacity: 0.5;
}

/* === Адаптивность === */
@media (max-width: 768px) {
    .container {
        padding-left: 12px;
        padding-right: 12px;
    }
    .card-body {
        padding: 1rem;
    }
}