:root {
    --bg-color: #ffffff;
    --primary-color: #2c5aa0;
    --text-color: #1a1a1a;
    --border-color: #2c5aa0;
    --light-bg: #f0f4fa;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: "Segoe UI", Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-size: 16px;
    line-height: 1.5;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

h1, h2, h3 {
    color: var(--primary-color);
    margin-bottom: 10px;
}

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

a:hover {
    text-decoration: underline;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin: 15px 0;
}

th, td {
    border: 1px solid var(--border-color);
    padding: 8px 12px;
    text-align: left;
}

th {
    background-color: var(--light-bg);
    font-weight: bold;
}

input[type="text"],
input[type="password"],
input[type="number"],
textarea,
select {
    width: 100%;
    padding: 8px;
    border: 1px solid var(--border-color);
    border-radius: 3px;
    font-size: 14px;
}

button, .btn {
    background-color: var(--primary-color);
    color: #ffffff;
    border: none;
    padding: 8px 20px;
    border-radius: 3px;
    cursor: pointer;
    font-size: 14px;
}

button:hover, .btn:hover {
    background-color: #1e3d6f;
}

.message {
    padding: 10px;
    margin: 10px 0;
    border-radius: 3px;
}

.message.error {
    background-color: #fde8e8;
    color: #c01c1c;
    border: 1px solid #c01c1c;
}

.message.success {
    background-color: #e8f5e9;
    color: #2e7d32;
    border: 1px solid #2e7d32;
}

.flash {
    padding: 10px;
    margin: 10px 0;
    border-radius: 3px;
}

.flash-error {
    background-color: #fde8e8;
    color: #c01c1c;
    border: 1px solid #c01c1c;
}

.flash-success {
    background-color: #e8f5e9;
    color: #2e7d32;
    border: 1px solid #2e7d32;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}

.lesson-page {
    display: flex;
    flex-direction: column;
    height: calc(100vh - 40px);
}

.lesson-header {
    flex-shrink: 0;
}

.lesson-layout {
    display: flex;
    gap: 10px;
    flex: 1;
    min-height: 0;
}

.frame-tasks {
    flex: 0 0 220px;
    border: 1px solid var(--border-color);
    border-radius: 3px;
    padding: 10px;
    overflow-y: auto;
    background-color: var(--light-bg);
}

.frame-tasks h3 {
    margin-bottom: 8px;
    font-size: 16px;
}

.task-list {
    list-style: none;
}

.task-list-item {
    padding: 6px 8px;
    border-radius: 3px;
    cursor: pointer;
    margin-bottom: 3px;
}

.task-list-item:hover {
    background-color: #d0dffa;
}

.task-list-item.active {
    background-color: var(--primary-color);
}

.task-list-item.active a {
    color: #fff;
}

.frame-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 10px;
    min-width: 0;
}

.frame-statement {
    flex: 1;
    border: 1px solid var(--border-color);
    border-radius: 3px;
    padding: 15px;
    overflow-y: auto;
    background-color: #fff;
}

.frame-editor {
    flex: 0 0 300px;
    border: 1px solid var(--border-color);
    border-radius: 3px;
    padding: 10px;
    background-color: #fff;
    display: flex;
    flex-direction: column;
}

.statement-header h2 {
    margin-bottom: 15px;
}

.statement-section {
    margin-bottom: 20px;
}

.statement-section h3 {
    font-size: 16px;
    margin-bottom: 8px;
    border-bottom: 1px solid var(--light-bg);
    padding-bottom: 4px;
}

.statement-section p {
    white-space: pre-wrap;
}

.limits-table {
    width: auto;
}

.limits-table td {
    border: none;
    padding: 2px 12px 2px 0;
}

.examples-table pre {
    margin: 0;
    white-space: pre-wrap;
    word-break: break-all;
}

.editor-container {
    display: flex;
    flex-direction: column;
    height: 100%;
    gap: 8px;
}

.editor-controls {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-shrink: 0;
}

.editor-controls label {
    font-weight: bold;
    white-space: nowrap;
}

#code-editor {
    flex: 1;
    font-family: "Consolas", "Courier New", monospace;
    font-size: 14px;
    resize: none;
    border: 1px solid var(--border-color);
    border-radius: 3px;
    padding: 8px;
}

.editor-actions {
    flex-shrink: 0;
}

.results-area {
    flex: 0 0 80px;
    border: 1px solid var(--border-color);
    border-radius: 3px;
    padding: 8px;
    overflow-y: auto;
    background-color: var(--light-bg);
    font-size: 14px;
}

.results-placeholder {
    color: #888;
}

/* CodeMirror */
.CodeMirror {
    flex: 1;
    height: 100%;
    border: 1px solid var(--border-color);
    border-radius: 3px;
    font-family: "Consolas", "Courier New", monospace;
    font-size: 14px;
}

.editor-container .CodeMirror {
    flex: 1;
    min-height: 200px;
}