:root {
    --color-primary: #2f6fed;
    --color-text: #1c1c1c;
    --color-bg: #f7f8fa;
    --color-border: #e0e2e7;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    color: var(--color-text);
    background: var(--color-bg);
}

.site-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 1.5rem;
    background: #fff;
    border-bottom: 1px solid var(--color-border);
}

.site-header .logo {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--color-primary);
    text-decoration: none;
}

.lang-switch a {
    margin-left: 0.5rem;
    padding: 0.25rem 0.5rem;
    text-decoration: none;
    color: var(--color-text);
    border: 1px solid var(--color-border);
    border-radius: 4px;
    font-size: 0.85rem;
}

.lang-switch a.active {
    background: var(--color-primary);
    color: #fff;
    border-color: var(--color-primary);
}

.site-main {
    max-width: 960px;
    margin: 0 auto;
    padding: 3rem 1.5rem;
}

.hero {
    text-align: center;
}

.hero h1 {
    font-size: 2rem;
    margin-bottom: 0.75rem;
}

.hero p {
    color: #555;
    margin-bottom: 1.5rem;
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background: var(--color-primary);
    color: #fff;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 600;
}

.site-footer {
    text-align: center;
    padding: 1.5rem;
    color: #888;
    font-size: 0.85rem;
}

.user-nav {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-left: 1rem;
    font-size: 0.9rem;
}

.user-nav a {
    color: var(--color-primary);
    text-decoration: none;
}

.user-nav__name {
    color: #555;
}

.auth-page {
    max-width: 420px;
    margin: 0 auto;
}

.auth-page form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin: 1.5rem 0;
}

.auth-page label {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    font-size: 0.9rem;
    color: #333;
}

.auth-page label.checkbox {
    flex-direction: row;
    align-items: center;
}

.auth-page input[type="email"],
.auth-page input[type="password"],
.auth-page input[type="text"] {
    padding: 0.6rem 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: 6px;
    font-size: 1rem;
}

.auth-page button {
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.field-error {
    color: #c0392b;
    font-size: 0.85rem;
    margin: -0.5rem 0 0;
}

.alert {
    padding: 0.75rem 1rem;
    border-radius: 6px;
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

.alert-success {
    background: #e6f6ea;
    color: #1e7e34;
    border: 1px solid #b6e4c2;
}

.alert-error {
    background: #fdecea;
    color: #c0392b;
    border: 1px solid #f5c6cb;
}

.nauka-breadcrumb {
    color: #777;
    font-size: 0.85rem;
    margin-bottom: 0.5rem;
}

.nauka-picker,
.nauka-selection,
.nauka-session {
    max-width: 640px;
    margin: 0 auto;
    text-align: center;
}

.nauka-list {
    list-style: none;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin: 1.5rem 0;
}

.nauka-list a {
    display: block;
    padding: 0.85rem 1rem;
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: 8px;
    text-decoration: none;
    color: var(--color-text);
    font-weight: 600;
}

.nauka-list a:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.nauka-list li {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.nauka-list a.nauka-list__all {
    display: inline-block;
    align-self: flex-start;
    padding: 0;
    background: none;
    border: none;
    font-weight: 400;
    font-size: 0.85rem;
    text-decoration: underline;
    color: var(--color-primary);
}

.nauka-level-all {
    margin: 0.5rem 0 1.5rem;
}

.nauka-level-all a {
    font-size: 0.9rem;
    text-decoration: underline;
    color: var(--color-primary);
}

.nauka-modes {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    margin: 2rem 0;
    flex-wrap: wrap;
}

.nauka-mode {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.nauka-mode__select,
.btn-link {
    background: none;
    border: none;
    color: var(--color-primary);
    text-decoration: underline;
    font-size: 0.85rem;
    cursor: pointer;
    padding: 0;
}

.nauka-hint {
    color: #777;
    font-size: 0.85rem;
    margin-top: 1.5rem;
}

.nauka-selection__actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.nauka-selection__list {
    list-style: none;
    padding: 0;
    text-align: left;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    max-height: 420px;
    overflow-y: auto;
    margin-bottom: 1.5rem;
}

.nauka-selection__list li {
    padding: 0.5rem 0.75rem;
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: 6px;
}

.nauka-selection__list label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
}

.flashcard {
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 2.5rem 1.5rem;
    margin: 1.5rem 0;
}

.flashcard__front {
    font-size: 1.75rem;
    font-weight: 700;
    margin: 0 0 1rem;
}

.flashcard__back {
    font-size: 1.4rem;
    color: var(--color-primary);
    margin: 0 0 0.75rem;
}

.flashcard__example {
    color: #666;
    font-size: 0.95rem;
    margin: 0 0 1.25rem;
}

.flashcard__audio-btn {
    display: inline-block;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.1em;
    line-height: 1;
    padding: 0.15rem 0.35rem;
    margin-left: 0.35rem;
    vertical-align: middle;
    border-radius: 6px;
}

.flashcard__audio-btn[hidden] {
    display: none;
}

.flashcard__audio-btn:hover {
    background: #f0f0f0;
}

.flashcard__answer-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 1rem;
}

.btn-correct {
    background: #1e7e34;
    color: #fff;
}

.btn-incorrect {
    background: #c0392b;
    color: #fff;
}

.nauka-session__progress {
    color: #777;
    font-size: 0.9rem;
}

.nauka-results h2 {
    margin-bottom: 1rem;
}

.postepy {
    max-width: 720px;
    margin: 0 auto;
}

.postepy__pair {
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: 10px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.postepy__pair h2 {
    margin-top: 0;
    font-size: 1.15rem;
}

.postepy__summary {
    list-style: none;
    padding: 0;
    margin: 0 0 1.25rem;
    color: #555;
    font-size: 0.9rem;
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.postepy__table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.postepy__table {
    width: 100%;
    min-width: 460px;
    border-collapse: collapse;
    font-size: 0.9rem;
}

.postepy__table th,
.postepy__table td {
    padding: 0.5rem;
    text-align: center;
    border: 1px solid var(--color-border);
    white-space: nowrap;
}

.postepy__table thead th:first-child {
    background: transparent;
    border: none;
}

.postepy__table tbody th {
    text-align: left;
    background: #f7f8fa;
}

.admin {
    max-width: 960px;
    margin: 0 auto;
}

.admin-nav {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--color-border);
    flex-wrap: wrap;
}

.admin__header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.admin__header-actions {
    display: flex;
    gap: 0.5rem;
}

.admin-dashboard__stats {
    list-style: none;
    padding: 0;
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.admin-dashboard__stats li {
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: 10px;
    padding: 1.25rem 1.75rem;
}

.admin-dashboard__stats strong {
    display: block;
    font-size: 1.5rem;
}

.admin-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
    background: #fff;
}

.admin-table th,
.admin-table td {
    padding: 0.5rem 0.6rem;
    text-align: left;
    border-bottom: 1px solid var(--color-border);
}

.admin-table__actions {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.admin-table__actions form {
    display: inline;
}

.admin-table__actions button {
    background: none;
    border: none;
    padding: 0;
    color: #1a56db;
    text-decoration: underline;
    cursor: pointer;
    font: inherit;
}

.admin-form {
    max-width: 520px;
    display: flex;
    flex-direction: column;
    gap: 0.9rem;
}

.admin-form label {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
    font-weight: 600;
    font-size: 0.9rem;
}

.admin-form input,
.admin-form select,
.admin-form textarea {
    font-weight: normal;
    padding: 0.5rem;
    border: 1px solid var(--color-border);
    border-radius: 6px;
    font-size: 1rem;
}

.admin-form__checkbox {
    flex-direction: row !important;
    align-items: center;
}

.admin-form__actions {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.admin-form__audio {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-top: -0.4rem;
}

.admin-form__audio audio {
    height: 32px;
    max-width: 220px;
}

.admin-form__audio form {
    margin: 0;
}

.admin-form__audio button {
    font-size: 0.85rem;
    padding: 0.35rem 0.6rem;
}

.admin-hint {
    color: #555;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.admin-pagination {
    display: flex;
    gap: 1rem;
    align-items: center;
    margin-top: 1rem;
    font-size: 0.9rem;
}

.btn--secondary {
    background: #eee;
    color: #222;
}

.concept-page {
    max-width: 640px;
    margin: 0 auto;
}

.concept-page__heading {
    margin: 0 0 1.5rem;
    font-size: 1.75rem;
}

.concept-block {
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: 1rem 1.25rem;
    margin-bottom: 1.25rem;
}

.concept-block h2 {
    margin: 0 0 0.5rem;
    font-size: 1rem;
    color: #555;
}

.concept-block__main {
    font-size: 1.15rem;
    font-weight: 600;
    margin: 0 0 0.35rem;
}

.concept-block__secondary {
    color: #666;
    margin: 0;
}

.concept-audio-btn {
    display: inline-block;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1em;
    line-height: 1;
    padding: 0.15rem 0.35rem;
    margin-left: 0.35rem;
    vertical-align: middle;
    border-radius: 6px;
}

.concept-audio-btn:hover {
    background: #f0f0f0;
}

.nauka-list--inline {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin: 0;
}

.nauka-list--inline a {
    padding: 0.4rem 0.75rem;
    font-weight: 400;
    font-size: 0.9rem;
}

.admin-search {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.admin-search input[type="text"] {
    flex: 1;
    max-width: 320px;
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: 6px;
}