:root {
    --mui-primary: #1976d2;
    --mui-primary-dark: #1565c0;
    --mui-primary-light: #42a5f5;
    --mui-success: #2e7d32;
    --mui-success-bg: #e8f5e9;
    --mui-error: #d32f2f;
    --mui-error-bg: #ffebee;
    --mui-info: #0288d1;
    --mui-info-bg: #e1f5fe;
    --mui-warning: #ed6c02;
    --mui-text-primary: rgba(0, 0, 0, 0.87);
    --mui-text-secondary: rgba(0, 0, 0, 0.6);
    --mui-divider: rgba(0, 0, 0, 0.12);
    --mui-bg: #f5f5f5;
    --mui-paper: #ffffff;
    --mui-radius: 4px;
    --mui-radius-lg: 8px;
    --mui-shadow-1: 0px 2px 1px -1px rgba(0,0,0,0.2), 0px 1px 1px 0px rgba(0,0,0,0.14), 0px 1px 3px 0px rgba(0,0,0,0.12);
    --mui-shadow-3: 0px 3px 3px -2px rgba(0,0,0,0.2), 0px 3px 4px 0px rgba(0,0,0,0.14), 0px 1px 8px 0px rgba(0,0,0,0.12);
    --mui-shadow-appbar: 0px 2px 4px -1px rgba(0,0,0,0.2), 0px 4px 5px 0px rgba(0,0,0,0.14), 0px 1px 10px 0px rgba(0,0,0,0.12);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    font-family: Roboto, Helvetica, Arial, sans-serif;
    font-size: 14px;
    line-height: 1.5;
    color: var(--mui-text-primary);
    background: var(--mui-bg);
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--mui-primary);
}

button,
input,
textarea,
select {
    font: inherit;
}

/* Typography */
.mui-h4 {
    margin: 0 0 4px;
    font-size: 2.125rem;
    font-weight: 400;
    line-height: 1.235;
    letter-spacing: 0.00735em;
}

.mui-h5 {
    margin: 0 0 4px;
    font-size: 1.5rem;
    font-weight: 400;
    line-height: 1.334;
}

.mui-h6 {
    margin: 0 0 12px;
    font-size: 1.25rem;
    font-weight: 500;
    line-height: 1.6;
}

.mui-body1 {
    margin: 0;
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.5;
}

.mui-body2 {
    margin: 0;
    font-size: 0.875rem;
    font-weight: 400;
    line-height: 1.43;
}

.mui-text-secondary {
    color: var(--mui-text-secondary);
}

.mui-link {
    font-weight: 500;
    text-decoration: none;
}

.mui-link:hover {
    text-decoration: underline;
}

/* AppBar */
.mui-appbar {
    position: sticky;
    top: 0;
    z-index: 1100;
    display: flex;
    flex-wrap: nowrap;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    height: 64px;
    padding: 0 24px;
    color: #fff;
    background: var(--mui-primary);
    box-shadow: var(--mui-shadow-appbar);
}

.mui-appbar-brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    color: #fff;
    text-decoration: none;
    min-width: 0;
}

.mui-appbar-icon {
    font-size: 28px;
}

.mui-appbar-title {
    font-size: 1.25rem;
    font-weight: 500;
    line-height: 1.2;
    white-space: nowrap;
}

.mui-appbar-actions {
    display: flex;
    flex-wrap: nowrap;
    align-items: center;
    justify-content: flex-end;
    gap: 4px;
}

.mui-appbar-user {
    margin-right: 8px;
    max-width: 220px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* Layout */
.mui-page {
    padding: 24px 16px 48px;
}

.mui-container {
    max-width: 1120px;
    margin: 0 auto;
}

.mui-container-narrow {
    max-width: 920px;
}

.mui-page-header {
    margin-bottom: 24px;
}

.mui-section-title {
    margin-top: 28px;
}

.mui-auth-layout {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 48px 16px;
    min-height: calc(100vh - 64px);
}

.mui-auth-card {
    width: 100%;
    max-width: 420px;
    padding: 36px 32px;
}

.mui-auth-header {
    text-align: center;
    margin-bottom: 28px;
}

.mui-auth-avatar {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 56px;
    height: 56px;
    margin-bottom: 12px;
    border-radius: 50%;
    color: var(--mui-primary);
    background: rgba(25, 118, 210, 0.08);
}

.mui-auth-avatar .material-icons-outlined {
    font-size: 28px;
}

.mui-auth-icon {
    font-size: 40px;
    color: var(--mui-primary);
    margin-bottom: 8px;
}

.mui-auth-footer {
    margin-top: 24px;
    text-align: center;
}

.mui-form {
    display: flex;
    flex-direction: column;
    width: 100%;
}

/* Paper / elevation */
.mui-paper {
    background: var(--mui-paper);
    border-radius: var(--mui-radius-lg);
}

.elevation-1 {
    box-shadow: var(--mui-shadow-1);
}

.elevation-3 {
    box-shadow: var(--mui-shadow-3);
}

/* Buttons */
.mui-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    min-width: 64px;
    height: 36px;
    padding: 6px 16px;
    border: none;
    border-radius: var(--mui-radius);
    text-decoration: none;
    text-transform: uppercase;
    letter-spacing: 0.02857em;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 150ms, box-shadow 150ms, border-color 150ms;
    white-space: nowrap;
}

.mui-btn .material-icons-outlined {
    font-size: 18px;
}

.mui-btn-contained {
    color: #fff;
    background: var(--mui-primary);
    box-shadow: var(--mui-shadow-1);
}

.mui-btn-contained:hover {
    background: var(--mui-primary-dark);
}

.mui-btn-success {
    background: var(--mui-success);
}

.mui-btn-success:hover {
    background: #1b5e20;
}

.mui-btn-outlined {
    color: var(--mui-primary);
    background: transparent;
    border: 1px solid rgba(25, 118, 210, 0.5);
}

.mui-btn-outlined:hover {
    background: rgba(25, 118, 210, 0.04);
    border-color: var(--mui-primary);
}

.mui-btn-text {
    color: var(--mui-primary);
    background: transparent;
}

.mui-btn-text:hover {
    background: rgba(25, 118, 210, 0.04);
}

.mui-btn-light {
    color: #fff;
}

.mui-btn-light:hover {
    background: rgba(255, 255, 255, 0.12);
}

.mui-btn-outlined.mui-btn-light {
    border-color: rgba(255, 255, 255, 0.7);
    color: #fff;
}

.mui-btn-contrast {
    color: var(--mui-primary);
    background: #fff;
}

.mui-btn-contrast:hover {
    background: #f5f5f5;
}

.mui-btn-block {
    width: 100%;
}

.mui-btn-sm {
    height: 30px;
    padding: 4px 10px;
    font-size: 0.8125rem;
}

.mui-back {
    margin-bottom: 12px;
    text-transform: none;
    letter-spacing: normal;
}

/* Fields */
.mui-form,
.mui-form-card {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.mui-form-card {
    padding: 20px;
    margin-top: 12px;
    margin-bottom: 20px;
}

.mui-field {
    display: flex;
    flex-direction: column;
    gap: 6px;
    margin-bottom: 14px;
}

.mui-field-label {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--mui-text-secondary);
    letter-spacing: 0.03em;
}

.mui-input,
.mui-textarea {
    width: 100%;
    padding: 12px 14px;
    color: var(--mui-text-primary);
    background: transparent;
    border: 1px solid rgba(0, 0, 0, 0.23);
    border-radius: var(--mui-radius);
    outline: none;
    transition: border-color 150ms, box-shadow 150ms;
}

.mui-input:hover,
.mui-textarea:hover {
    border-color: rgba(0, 0, 0, 0.87);
}

.mui-input:focus,
.mui-textarea:focus {
    border-color: var(--mui-primary);
    border-width: 2px;
    padding: 11px 13px;
}

.mui-textarea {
    min-height: 96px;
    resize: vertical;
}

.mui-code {
    font-family: Consolas, "Courier New", monospace;
    font-size: 0.9rem;
    line-height: 1.45;
    min-height: 140px;
    background: #fafafa;
}

.mui-checkbox {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 16px;
    color: var(--mui-text-primary);
}

/* Chips */
.mui-chip {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    height: 32px;
    padding: 0 12px;
    border-radius: 16px;
    background: rgba(0, 0, 0, 0.08);
    color: var(--mui-text-primary);
    font-size: 0.8125rem;
    font-weight: 400;
}

.mui-chip-light {
    background: rgba(255, 255, 255, 0.18);
    color: #fff;
}

.mui-chip-outline {
    background: transparent;
    border: 1px solid var(--mui-divider);
}

.mui-chip-success {
    background: var(--mui-success-bg);
    color: var(--mui-success);
}

.mui-chip-icon {
    font-size: 16px !important;
}

.mui-chip-row {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 12px;
}

/* Alerts / messages (compat with showMessage) */
.mui-alert,
.message {
    margin: 12px 0;
    padding: 12px 16px;
    border-radius: var(--mui-radius);
    font-size: 0.875rem;
}

.mui-alert-info,
.status {
    color: #014361;
    background: var(--mui-info-bg);
}

.mui-alert-success,
.message-success {
    color: #1e4620;
    background: var(--mui-success-bg);
}

.mui-alert-error,
.message-error {
    color: #5f2120;
    background: var(--mui-error-bg);
}

/* Cards / grids */
.mui-grid,
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 16px;
}

.mui-card,
.course-card {
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding: 16px;
    color: inherit;
    text-decoration: none;
    background: var(--mui-paper);
    border-radius: var(--mui-radius-lg);
    box-shadow: var(--mui-shadow-1);
    transition: box-shadow 150ms, transform 150ms;
}

.mui-card:hover,
.course-card:hover {
    box-shadow: var(--mui-shadow-3);
    transform: translateY(-1px);
}

.mui-card h3,
.course-card h3 {
    margin: 0;
    font-size: 1.15rem;
    font-weight: 500;
}

.mui-card p,
.course-card p {
    margin: 0;
    color: var(--mui-text-secondary);
    flex: 1;
}

.mui-card-top,
.card-top {
    display: flex;
    justify-content: space-between;
    gap: 8px;
    align-items: flex-start;
}

.mui-card-meta,
.card-meta,
.meta-line {
    color: var(--mui-text-secondary);
    font-size: 0.8125rem;
}

.mui-stats-grid,
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 16px;
    margin-bottom: 8px;
}

.mui-stat-card,
.stat-card {
    padding: 20px;
}

.mui-stat-icon {
    color: var(--mui-primary);
    margin-bottom: 8px;
}

.mui-stat-label,
.stat-label {
    color: var(--mui-text-secondary);
    font-size: 0.875rem;
}

.mui-stat-value,
.stat-value {
    margin-top: 4px;
    font-size: 2rem;
    font-weight: 500;
    color: var(--mui-text-primary);
}

/* Lists */
.mui-list,
.stack-list,
.task-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.mui-list-item,
.stack-item,
.task-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    width: 100%;
    padding: 14px 16px;
    text-align: left;
    color: inherit;
    text-decoration: none;
    background: var(--mui-paper);
    border: none;
    border-radius: var(--mui-radius-lg);
    box-shadow: var(--mui-shadow-1);
    cursor: pointer;
    transition: background-color 150ms, box-shadow 150ms;
}

.mui-list-item:hover,
.stack-item:hover,
.task-row:hover,
.stack-item.active {
    background: #f0f7ff;
    box-shadow: var(--mui-shadow-3);
}

.stack-item.active {
    outline: 2px solid var(--mui-primary);
}

/* Two column */
.mui-two-col,
.teacher-grid {
    display: grid;
    grid-template-columns: 1fr 1.35fr;
    gap: 24px;
}

.mui-section-card {
    padding: 24px;
    margin-bottom: 16px;
}

.mui-section-card-header {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    align-items: flex-start;
}

.mui-trainer-card {
    padding: 24px;
}

.mui-accordion-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin: 20px 0;
}

.mui-accordion,
.task-info-panel {
    background: #fafafa;
    border: 1px solid var(--mui-divider);
    border-radius: var(--mui-radius);
    overflow: hidden;
}

.mui-accordion summary {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 14px;
    cursor: pointer;
    font-weight: 500;
    list-style: none;
}

.mui-accordion summary::-webkit-details-marker {
    display: none;
}

.mui-accordion-body,
.task-info-content {
    padding: 0 14px 14px;
}

.mui-actions,
.actions {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin: 8px 0 16px;
}

.mui-result {
    margin-top: 8px;
    padding-top: 16px;
    border-top: 1px solid var(--mui-divider);
}

.mui-result-header,
.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.mui-empty,
.empty-state,
.empty-result {
    padding: 24px;
    color: var(--mui-text-secondary);
    text-align: center;
    background: #fafafa;
    border-radius: var(--mui-radius);
}

.mui-table-wrap,
.table-wrapper {
    overflow: auto;
    border-radius: var(--mui-radius);
}

.mui-table,
.table-wrapper table,
#result-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--mui-paper);
}

.mui-table th,
.mui-table td,
.table-wrapper th,
.table-wrapper td,
#result-table th,
#result-table td {
    padding: 12px 16px;
    text-align: left;
    border-bottom: 1px solid var(--mui-divider);
}

.mui-table th,
.table-wrapper th,
#result-table th {
    font-weight: 500;
    color: var(--mui-text-secondary);
    background: #fafafa;
}

.schema-table {
    margin-bottom: 12px;
}

.schema-table ul {
    margin: 8px 0 0;
    padding-left: 18px;
}

.badge {
    display: inline-flex;
    align-items: center;
    height: 24px;
    padding: 0 10px;
    border-radius: 16px;
    background: rgba(0, 0, 0, 0.08);
    font-size: 0.75rem;
}

.badge-success {
    background: var(--mui-success-bg);
    color: var(--mui-success);
}

.primary-button {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    height: 36px;
    padding: 6px 16px;
    color: #fff;
    background: var(--mui-primary);
    border: none;
    border-radius: var(--mui-radius);
    text-transform: uppercase;
    font-weight: 500;
    cursor: pointer;
}

.secondary-button {
    display: inline-flex;
    align-items: center;
    height: 30px;
    padding: 4px 12px;
    color: var(--mui-error);
    background: transparent;
    border: 1px solid rgba(211, 47, 47, 0.5);
    border-radius: var(--mui-radius);
    cursor: pointer;
}

.secondary-button:hover {
    background: rgba(211, 47, 47, 0.04);
}

.muted {
    color: var(--mui-text-secondary);
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    margin-bottom: 12px;
    color: var(--mui-primary);
    text-decoration: none;
    font-weight: 500;
}

@media (max-width: 900px) {
    .mui-two-col,
    .teacher-grid {
        grid-template-columns: 1fr;
    }

    .mui-accordion-grid {
        grid-template-columns: 1fr;
    }

    .mui-section-card-header {
        flex-direction: column;
    }

    .mui-h4 {
        font-size: 1.6rem;
    }

    .mui-appbar {
        height: 56px;
        padding: 0 12px;
    }

    .mui-appbar-user {
        display: none;
    }

    .mui-appbar-actions .mui-btn {
        padding: 6px 10px;
        min-width: auto;
    }
}