/* ============================================================
   PYTHON LEARNING PLATFORM — MODERN UI (полный style.css)
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500&display=swap');

/* ---------- Переменные ---------- */
:root {
    --primary: #3776AB;
    --primary-dark: #2a5d87;
    --primary-light: #5a95c9;
    --accent: #FFD43B;
    --accent-dark: #f0c020;
    --bg: #f7f9fc;
    --surface: #ffffff;
    --text: #1a2332;
    --text-muted: #6b7a8f;
    --border: #e4e9f0;
    --success: #10b981;
    --danger: #ef4444;
    --shadow-sm: 0 1px 3px rgba(26, 35, 50, 0.06);
    --shadow-md: 0 4px 16px rgba(26, 35, 50, 0.08);
    --shadow-lg: 0 12px 32px rgba(26, 35, 50, 0.12);
    --radius: 14px;
    --radius-sm: 10px;
}

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

html, body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
}

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

::selection { background: var(--accent); color: var(--text); }

::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
    background: #cbd5e0;
    border-radius: 10px;
    border: 2px solid var(--bg);
}
::-webkit-scrollbar-thumb:hover { background: #94a3b8; }

/* ============================================================
   ГЛАВНАЯ (HERO)
   ============================================================ */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px 20px;
    position: relative;
    overflow: hidden;
    background: linear-gradient(135deg, #1e3c72 0%, #2a5298 50%, #3776AB 100%);
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(circle at 20% 20%, rgba(255, 212, 59, 0.15) 0%, transparent 45%),
        radial-gradient(circle at 80% 70%, rgba(90, 149, 201, 0.25) 0%, transparent 50%);
    pointer-events: none;
}

.hero::after {
    content: '';
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(255,255,255,0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px);
    background-size: 40px 40px;
    pointer-events: none;
    mask-image: radial-gradient(ellipse at center, black 30%, transparent 75%);
}

.hero > * { position: relative; z-index: 1; }

.hero h1 {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 800;
    letter-spacing: -0.03em;
    color: #fff;
    margin-bottom: 16px;
    text-align: center;
    line-height: 1.1;
    animation: fadeUp 0.8s ease-out;
}

.hero p {
    font-size: clamp(1rem, 2vw, 1.35rem);
    color: rgba(255, 255, 255, 0.85);
    margin-bottom: 48px;
    text-align: center;
    max-width: 600px;
    animation: fadeUp 0.8s ease-out 0.15s both;
}

.btn-start {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 18px 48px;
    font-size: 1.15rem;
    font-weight: 700;
    border-radius: 999px;
    background: var(--accent);
    color: #1a2332;
    box-shadow:
        0 8px 24px rgba(255, 212, 59, 0.35),
        0 0 0 0 rgba(255, 212, 59, 0.5);
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    border: none;
    cursor: pointer;
    animation: fadeUp 0.8s ease-out 0.3s both, pulse 3s ease-in-out 1.5s infinite;
    text-decoration: none;
}

.btn-start:hover {
    transform: translateY(-3px) scale(1.02);
    box-shadow:
        0 14px 32px rgba(255, 212, 59, 0.45),
        0 0 0 6px rgba(255, 212, 59, 0.15);
    color: #1a2332;
}
.btn-start:active { transform: translateY(-1px) scale(1); }

@keyframes fadeUp {
    from { opacity: 0; transform: translateY(24px); }
    to   { opacity: 1; transform: translateY(0); }
}

@keyframes pulse {
    0%, 100% { box-shadow: 0 8px 24px rgba(255, 212, 59, 0.35), 0 0 0 0 rgba(255, 212, 59, 0.5); }
    50%      { box-shadow: 0 8px 24px rgba(255, 212, 59, 0.35), 0 0 0 14px rgba(255, 212, 59, 0); }
}

/* ============================================================
   ВХОД
   ============================================================ */
.login-box {
    width: min(420px, calc(100% - 40px));
    margin: 8vh auto;
    background: var(--surface);
    padding: 40px 36px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border);
    animation: fadeUp 0.5s ease-out;
}

.login-box h2 {
    font-size: 1.75rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 28px;
    color: var(--text);
    letter-spacing: -0.02em;
}
.login-box h2::before { content: ''; display: inline-block; margin-right: 6px; }

.login-box input {
    width: 100%;
    padding: 14px 16px;
    margin-bottom: 14px;
    border: 1.5px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-family: inherit;
    background: #f9fafc;
    transition: all 0.2s;
    color: var(--text);
}
.login-box input:focus {
    outline: none;
    border-color: var(--primary);
    background: #fff;
    box-shadow: 0 0 0 4px rgba(55, 118, 171, 0.12);
}

.login-box button {
    width: 100%;
    padding: 14px;
    margin-top: 8px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    font-family: inherit;
    transition: all 0.2s;
    box-shadow: 0 4px 14px rgba(55, 118, 171, 0.3);
}
.login-box button:hover { transform: translateY(-1px); box-shadow: 0 6px 20px rgba(55, 118, 171, 0.4); }
.login-box button:active { transform: translateY(0); }

.hint {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-top: 24px;
    padding-top: 20px;
    border-top: 1px solid var(--border);
    line-height: 1.8;
}
.hint code {
    background: #f0f3f8;
    color: var(--primary-dark);
    padding: 2px 8px;
    border-radius: 6px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82rem;
    font-weight: 500;
}

.error {
    color: var(--danger);
    text-align: center;
    padding: 10px;
    background: #fef2f2;
    border-radius: var(--radius-sm);
    border: 1px solid #fecaca;
    margin-bottom: 8px;
    font-size: 0.92rem;
}

/* ============================================================
   TOPBAR
   ============================================================ */
.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: linear-gradient(135deg, var(--primary-dark), var(--primary));
    background-color: #1e293b;
    color: #fff;
    padding: 14px 32px;
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(8px);
}

.topbar > span {
    font-weight: 600;
    font-size: 0.98rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.topbar a {
    color: #fff;
    text-decoration: none;
    margin-left: 20px;
    font-weight: 500;
    font-size: 0.95rem;
    padding: 8px 14px;
    border-radius: 8px;
   border: none;
    transition: background 0.2s;
}
.topbar a:hover { background: rgba(255, 255, 255, 0.15); color: #fff; }

/* ============================================================
   КОНТЕЙНЕР
   ============================================================ */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 24px 80px;
    animation: fadeUp 0.4s ease-out;
}

.container > h1 {
    font-size: clamp(1.6rem, 3vw, 2.2rem);
    font-weight: 800;
    margin-bottom: 24px;
    letter-spacing: -0.02em;
    color: var(--text);
}

.container > h2 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    letter-spacing: -0.02em;
    color: var(--text);
}

.ok {
    color: var(--success);
    font-weight: 600;
    background: #ecfdf5;
    padding: 12px 18px;
    border-radius: var(--radius-sm);
    border-left: 4px solid var(--success);
    margin-bottom: 20px;
    display: inline-block;
}

/* ============================================================
   КАРТОЧКИ ТЕМ
   ============================================================ */
.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}

.topic-card {
    background: var(--surface);
    padding: 26px 24px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
}

.topic-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    opacity: 0;
    transition: opacity 0.3s;
}

.topic-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}
.topic-card:hover::before { opacity: 1; }

.topic-num {
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 6px;
}

.topic-card h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text);
    letter-spacing: -0.01em;
}

.status {
    font-size: 0.92rem;
    color: var(--text-muted);
    margin-bottom: 20px;
    line-height: 1.7;
    flex: 1;
}
.status b { color: #000; font-weight: 700; }

/* ---------- Кнопки ---------- */
.btn {
    display: inline-block;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff;
    padding: 11px 22px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    border: none;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 600;
    font-family: inherit;
    transition: all 0.2s;
    box-shadow: 0 2px 8px rgba(55, 118, 171, 0.25);
    align-self: flex-start;
}
.btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 14px rgba(55, 118, 171, 0.35);
    color: #fff;
}
.btn:active { transform: translateY(0); }
.btn:disabled {
    background: #cbd5e0;
    cursor: not-allowed;
    box-shadow: none;
    transform: none;
}

/* ============================================================
   ТЕОРИЯ
   ============================================================ */
.theory {
    background: var(--surface);
    padding: 32px 36px;
    border-radius: var(--radius);
    margin-bottom: 28px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    line-height: 1.75;
}
.theory h2 {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--primary-dark);
    margin-bottom: 14px;
}
.theory h3 {
    font-size: 1.15rem;
    font-weight: 600;
    margin: 20px 0 10px;
    color: var(--text);
}
.theory p { margin: 0 0 16px; color: var(--text); }
.theory p:last-child { margin-bottom: 0; }
.theory ul { margin: 0 0 16px; padding-left: 26px; }
.theory li { margin: 6px 0; }
.theory pre + p, .theory p + pre { margin-top: 16px; }
.theory strong { font-weight: 700; color: var(--primary-dark); }
.theory code {
    background: #f0f3f8;
    color: var(--primary-dark);
    padding: 2px 8px;
    border-radius: 5px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.9em;
    font-weight: 500;
}
.theory pre {
    background: #1e293b;
    color: #e2e8f0;
    padding: 20px 24px;
    border-radius: var(--radius-sm);
    overflow-x: auto;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.92rem;
    line-height: 1.7;
    margin: 14px 0;
    box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.05);
}
.theory pre code {
    background: transparent;
    color: inherit;
    padding: 0;
    font-size: inherit;
}
.theory b { color: var(--primary-dark); font-weight: 600; }

/* ============================================================
   ТЕСТ
   ============================================================ */
.question {
    background: var(--surface);
    padding: 20px 24px;
    margin: 14px 0;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    transition: all 0.2s;
}
.question:hover { border-color: var(--primary-light); }
.question p {
    font-weight: 500;
    margin-bottom: 10px;
    color: var(--text);
}
.question p b { color: var(--primary); font-weight: 700; margin-right: 4px; }
.question input {
    width: 100%;
    padding: 12px 16px;
    border: 1.5px solid var(--border);
    border-radius: 8px;
    font-size: 0.98rem;
    font-family: inherit;
    background: #f9fafc;
    transition: all 0.2s;
    color: var(--text);
}
.question input:focus {
    outline: none;
    border-color: var(--primary);
    background: #fff;
    box-shadow: 0 0 0 4px rgba(55, 118, 171, 0.1);
}

#quizResult {
    font-weight: 600;
    font-size: 1.05rem;
    margin-top: 20px;
    padding: 14px 18px;
    border-radius: var(--radius-sm);
    background: #f0f3f8;
    color: var(--text);
    display: inline-block;
}

#checkQuiz { margin-top: 16px; padding: 14px 32px; font-size: 1rem; }

/* ============================================================
   ПРАКТИКА
   ============================================================ */
.practice-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 28px;
    margin-top: 20px;
}
@media (max-width: 900px) { .practice-layout { grid-template-columns: 1fr; } }

.tasks, .editor {
    background: var(--surface);
    padding: 26px 28px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
}

.tasks h3, .editor h3 {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--primary-dark);
    margin-bottom: 18px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--border);
}

.task { padding: 16px 0; border-bottom: 1px solid var(--border); }
.task:last-of-type { border-bottom: none; }
.task > b { color: var(--primary); font-weight: 700; font-size: 0.95rem; }
.task > div { margin: 8px 0; color: var(--text); font-size: 0.95rem; }

.stdin-hint {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin: 8px 0;
    padding: 8px 12px;
    background: #f9fafc;
    border-radius: 6px;
    border-left: 3px solid var(--accent);
}
.stdin-hint code {
    background: #fff;
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'JetBrains Mono', monospace;
    color: var(--text);
    font-weight: 500;
}

.btn-check {
    margin-top: 10px;
    padding: 8px 18px;
    background: linear-gradient(135deg, #10b981, #059669);
    color: #fff;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 600;
    font-family: inherit;
    transition: all 0.2s;
    box-shadow: 0 2px 8px rgba(16, 185, 129, 0.25);
}
.btn-check:hover { transform: translateY(-1px); box-shadow: 0 4px 14px rgba(16, 185, 129, 0.35); }
.btn-check:active { transform: translateY(0); }

.task-status { display: inline-block; margin-left: 10px; font-size: 0.9rem; font-weight: 500; }

/* ---------- Редактор кода ---------- */
.editor textarea {
    width: 100%;
    min-height: 280px;
    padding: 18px;
    font-family: 'JetBrains Mono', 'Consolas', monospace;
    font-size: 14px;
    line-height: 1.6;
    border: 1px solid #2d3748;
    border-radius: var(--radius-sm);
    background: #1e293b;
    color: #e2e8f0;
    resize: vertical;
    transition: box-shadow 0.2s;
    tab-size: 4;
}
.editor textarea:focus { outline: none; box-shadow: 0 0 0 4px rgba(55, 118, 171, 0.15); }

.editor h4 {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin: 20px 0 10px;
}

.output {
    background: #0f172a;
    color: #4ade80;
    padding: 18px;
    border-radius: var(--radius-sm);
    min-height: 80px;
    white-space: pre-wrap;
    max-height: 240px;
    overflow-y: auto;
    font-family: 'JetBrains Mono', monospace;
    font-size: 13.5px;
    line-height: 1.6;
    border: 1px solid #1e293b;
}
.output:empty::before { content: 'Вывод появится здесь…'; color: #475569; font-style: italic; }

.final {
    margin-top: 20px;
    padding: 18px 20px;
    font-size: 1.15rem;
    border-radius: var(--radius-sm);
    background: linear-gradient(135deg, #eff6ff, #f0f9ff);
    border-left: 4px solid var(--primary);
    color: var(--text);
}
.final b { color: var(--primary-dark); }
#finalScore { color: var(--primary); font-weight: 800; font-size: 1.3rem; }

#pyInitMsg {
    font-size: 0.9rem;
    padding: 12px 16px;
    border-radius: 8px;
    background: #f0f3f8;
    margin-bottom: 16px;
}

/* ============================================================
   ТАБЛИЦА (ученики / уроки)
   ============================================================ */
.filters {
    display: flex;
    gap: 24px;
    margin-bottom: 24px;
    flex-wrap: wrap;
    background: var(--surface);
    padding: 20px 24px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    align-items: center;
}
.filters label {
    display: flex;
    flex-direction: column;
    gap: 6px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}
.filters select {
    padding: 10px 14px;
    border-radius: 8px;
    border: 1.5px solid var(--border);
    font-size: 0.95rem;
    font-family: inherit;
    font-weight: 500;
    background: #f9fafc;
    color: var(--text);
    cursor: pointer;
    transition: all 0.2s;
    min-width: 180px;
}
.filters select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(55, 118, 171, 0.1);
    background: #fff;
}
.filters-note {
    font-size: 0.9rem;
    color: var(--text-muted);
    display: flex;
    align-items: flex-end;
    gap: 4px;
    padding-bottom: 6px;
}
.filters-note b { color: var(--primary-dark); font-size: 1rem; }

.students-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    background: var(--surface);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border);
}
.students-table thead th {
    background: linear-gradient(135deg, var(--primary-dark), var(--primary));
    color: #fff;
    padding: 16px 18px;
    text-align: left;
    font-weight: 600;
    font-size: 0.82rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
}
.students-table tbody td {
    padding: 14px 18px;
    border-bottom: 1px solid var(--border);
    font-size: 0.95rem;
    color: var(--text);
}
.students-table tbody tr:last-child td { border-bottom: none; }
.students-table tbody tr { transition: background 0.15s; }
.students-table tbody tr:hover { background: #f0f6ff; }
.students-table tbody td:first-child { color: var(--text-muted); font-weight: 600; font-size: 0.88rem; }
.students-table tbody td b { color: var(--primary); font-size: 1.05rem; font-weight: 700; }

/* ============================================================
   КАБИНЕТ: САЙДБАР + КОНТЕНТ
   ============================================================ */
.teacher-layout {
    display: grid;
    grid-template-columns: 260px 1fr;
    min-height: calc(100vh - 60px);
}
.sidebar {
    background: #fff;
    border-right: 1px solid var(--border);
    padding: 28px 20px;
    box-shadow: 2px 0 8px rgba(26, 35, 50, 0.03);
    position: sticky;
    /* Keep the sidebar below the sticky top bar so its title is never covered. */
    top: 76px;
    align-self: start;
    height: calc(100vh - 76px);
    max-height: calc(100vh - 76px);
    box-sizing: border-box;
    overflow-y: auto;
}
.sidebar-title {
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-muted);
    margin-bottom: 14px;
    padding: 0 12px;
}
.sidebar-nav { display: flex; flex-direction: column; gap: 4px; }
.sidebar-link {
    display: block;
    padding: 12px 16px;
    border-radius: var(--radius-sm);
    color: var(--text);
    font-weight: 500;
    font-size: 0.95rem;
    transition: all 0.2s;
    text-decoration: none;
}
.sidebar-link:hover { background: #f0f6ff; color: var(--primary-dark); }
.sidebar-link.active {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff;
    font-weight: 600;
    box-shadow: 0 4px 12px rgba(55, 118, 171, 0.25);
}
.teacher-main { padding: 32px 36px 80px; overflow-x: auto; }
.teacher-main > h2 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    letter-spacing: -0.02em;
    color: var(--text);
}

/* Flash-уведомления */
.flash {
    padding: 12px 18px;
    background: #ecfdf5;
    border-left: 4px solid var(--success);
    color: #065f46;
    border-radius: 8px;
    font-weight: 500;
    margin-bottom: 20px;
    animation: fadeUp 0.35s ease-out;
}
.flash.error-flash {
    background: #fef2f2;
    border-left-color: var(--danger);
    color: #991b1b;
}

/* ============================================================
   ПРОФИЛЬ
   ============================================================ */
.profile-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 24px;
}
@media (max-width: 900px) { .profile-grid { grid-template-columns: 1fr; } }

.card {
    background: #fff;
    padding: 26px 28px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
}
.card h3 {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--primary-dark);
    margin-bottom: 18px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--border);
}
.profile-grid .card h3:not(:first-child) { margin-top: 24px; }

.profile-form label {
    display: block;
    margin-bottom: 14px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}
.profile-form input,
.profile-form textarea {
    display: block;
    width: 100%;
    margin-top: 6px;
    padding: 11px 14px;
    border: 1.5px solid var(--border);
    border-radius: 8px;
    background: #f9fafc;
    font-size: 0.95rem;
    font-family: inherit;
    text-transform: none;
    letter-spacing: normal;
    color: var(--text);
    font-weight: 500;
    transition: all 0.2s;
}
.profile-form input:focus,
.profile-form textarea:focus {
    outline: none;
    border-color: var(--primary);
    background: #fff;
    box-shadow: 0 0 0 4px rgba(55, 118, 171, 0.1);
}
.profile-form input:disabled {
    background: #eef1f6;
    color: #6b7a8f;
    cursor: not-allowed;
}
.profile-form textarea { resize: vertical; min-height: 90px; }
.profile-form .btn { margin-top: 8px; }

/* ============================================================
   АВАТАРКИ
   ============================================================ */
.avatar {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    object-fit: cover;
    flex-shrink: 0;
    font-weight: 700;
    color: #fff;
    text-shadow: 0 1px 2px rgba(0,0,0,0.15);
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
    user-select: none;
}

.topbar-user {
    display: flex;
    align-items: center;
    gap: 12px;
    color: #fff;
    font-weight: 600;
}
.topbar-user small {
    opacity: 0.75;
    font-weight: 400;
    font-size: 0.85em;
}

.avatar-preview { text-align: center; padding: 20px 0 24px; }

.avatar-form {
    display: flex;
    flex-direction: column;
    gap: 12px;
    align-items: stretch;
}
.file-label {
    position: relative;
    display: block;
    cursor: pointer;
    text-align: center;
}
.file-label input[type="file"] {
    position: absolute;
    width: 1px;
    height: 1px;
    opacity: 0;
    overflow: hidden;
}
.file-label .btn {
    display: block;
    text-align: center;
    background: #eef1f6;
    color: var(--primary-dark);
    box-shadow: none;
}
.file-label .btn:hover { background: #e0e7f1; transform: none; }
.avatar-form button.btn { margin-top: 4px; }

/* ============================================================
   ПРОГРАММА КУРСОВ (модули)
   ============================================================ */
.module-card {
    background: #fff;
    padding: 26px 28px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    margin-bottom: 24px;
    transition: box-shadow 0.25s;
}
.module-card:hover { box-shadow: var(--shadow-md); }

.module-head {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 20px;
    margin-bottom: 18px;
}
.module-head h3 {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--primary-dark);
    margin-bottom: 6px;
}
.module-desc { color: var(--text-muted); font-size: 0.92rem; line-height: 1.6; }

.module-percent { text-align: right; flex-shrink: 0; }
.percent-value {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--primary);
    line-height: 1;
    letter-spacing: -0.02em;
}
.percent-label {
    font-size: 0.72rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-muted);
    margin-top: 4px;
    font-weight: 600;
}

.progress-bar {
    height: 10px;
    background: #e9eef5;
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 20px;
    box-shadow: inset 0 1px 2px rgba(0,0,0,0.04);
}
.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), #5a95c9, var(--accent));
    border-radius: 10px;
    transition: width 0.6s ease-out;
    min-width: 4px;
}

.lessons-table thead th {
    background: #f5f8fc;
    color: var(--primary-dark);
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.06em;
    border-bottom: 2px solid var(--border);
}
.lessons-table tbody tr:hover { background: #f9fbff; }

.mini-bar {
    display: inline-block;
    width: 120px;
    height: 7px;
    background: #e9eef5;
    border-radius: 10px;
    overflow: hidden;
    vertical-align: middle;
    margin-right: 8px;
}
.mini-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    border-radius: 10px;
    transition: width 0.4s ease-out;
}
.mini-label {
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--primary-dark);
    vertical-align: middle;
}

/* ============================================================
   АДАПТИВНОСТЬ
   ============================================================ */
/* Компактная боковая панель для небольших ноутбуков и планшетов в альбомной ориентации */
@media (min-width: 801px) and (max-width: 1000px) {
    .teacher-layout { grid-template-columns: 210px minmax(0, 1fr); }
    .sidebar { padding: 22px 12px; }
    .sidebar-title { padding: 0 8px; font-size: 0.7rem; letter-spacing: 0.05em; }
    .sidebar-link { padding: 10px 10px; font-size: 0.86rem; overflow-wrap: anywhere; }
    .teacher-main { min-width: 0; padding: 26px 20px 70px; }
}

@media (max-width: 800px) {
    /* На небольших экранах меню становится компактной горизонтальной полосой,
       чтобы оно не растягивалось на несколько строк и не отодвигало контент вниз. */
    .teacher-layout {
        display: flex;
        flex-direction: column;
        min-width: 0;
    }
    .sidebar {
        position: static;
        width: 100%;
        height: auto;
        min-height: 0;
        max-height: none;
        overflow: visible;
        border-right: none;
        border-bottom: 1px solid var(--border);
        padding: 8px 12px;
        box-sizing: border-box;
    }
    .sidebar-nav {
        display: flex;
        flex-direction: row;
        flex-wrap: nowrap;
        gap: 8px;
        width: 100%;
        overflow-x: auto;
        overflow-y: hidden;
        padding: 2px 0 6px;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: thin;
    }
    .sidebar-title { display: none; }
    .sidebar-link {
        flex: 0 0 auto;
        white-space: nowrap;
        padding: 9px 13px;
        font-size: 0.88rem;
    }
    .teacher-main {
        width: 100%;
        min-width: 0;
        box-sizing: border-box;
        padding: 22px 18px 60px;
        overflow-x: auto;
    }
    .module-head { flex-direction: column; }
    .module-percent { text-align: left; }
}

@media (max-width: 640px) {
    .topbar { padding: 12px 16px; flex-wrap: wrap; gap: 8px; }
    .topbar > span { font-size: 0.88rem; }
    .topbar a { margin-left: 0; margin-right: 8px; padding: 6px 10px; font-size: 0.88rem; }
    .topbar-user { gap: 8px; }
    .container { padding: 24px 16px 60px; }
    .theory { padding: 22px 20px; }
    .login-box { padding: 32px 24px; }
    .filters { flex-direction: column; align-items: stretch; }
    .filters select { width: 100%; }
    .students-table { font-size: 0.85rem; }
    .students-table thead th,
    .students-table tbody td { padding: 10px 12px; }
}
.answer-options{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin-top:14px}.answer-option{display:flex;align-items:center;gap:9px;padding:12px 14px;border:1px solid #dce4ef;border-radius:9px;background:#f8fafc;cursor:pointer}.answer-option:has(input:checked){border-color:#3678aa;background:#edf6ff}.answer-option input{width:auto;flex-shrink:0}@media(max-width:650px){.answer-options{grid-template-columns:1fr}}


/* ---------- Единая зелёная тема PyStart ---------- */
:root {
    --primary: #2f8738;
    --primary-dark: #236b2b;
    --primary-light: #55a85c;
    --bg: #f5f8f5;
    --border: #dfe9df;
    --shadow-md: 0 4px 16px rgba(35, 107, 43, .09);
    --shadow-lg: 0 12px 32px rgba(35, 107, 43, .13);
}
a { color: var(--primary); }
a:hover { color: var(--primary-dark); }
.btn, .btn-check, .btn-start, .btn-finish, .sidebar-link.active,
.topbar, .login-box button {
    background: #32883b !important;
    color: #fff !important;
    border-color: transparent;
    transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
}
.btn, .btn-check, .btn-start, .btn-finish {
    box-shadow: 0 4px 12px rgba(50, 136, 59, .22);
}
.btn:hover, .btn-check:hover, .btn-start:hover, .btn-finish:hover,
.login-box button:hover, .sidebar-link.active:hover {
    background: #26712e !important;
    color: #fff !important;
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(38, 113, 46, .30);
}
.btn:disabled, .btn-check:disabled, .btn-finish:disabled {
    opacity: .55;
    cursor: not-allowed;
    transform: none;
}
.sidebar-link.active { box-shadow: 0 4px 12px rgba(50,136,59,.2); }
.topbar { background: linear-gradient(110deg, #287532, #399744) !important; }
.login-box {
    width: min(500px, calc(100% - 28px));
    padding: 42px 40px;
    background: #fff;
    border: 1px solid #dce9dc;
    border-radius: 20px;
    box-shadow: 0 18px 55px rgba(35, 107, 43, .16);
}
.login-box input:focus { border-color: #55a85c; box-shadow: 0 0 0 4px rgba(50,136,59,.13); }
.question { border: 1px solid var(--border); transition: border-color .18s, background .18s, box-shadow .18s; }
.question.question-correct { border: 2px solid #2f9b50; background: #f0fbf2; box-shadow: 0 0 0 2px rgba(47,155,80,.08); }
.question.question-wrong { border: 2px solid #dc4545; background: #fff3f3; box-shadow: 0 0 0 2px rgba(220,69,69,.08); }
.question-feedback { margin-top: 8px; font-weight: 700; }
.answer-input { width:100%; padding:12px 14px; border:1px solid var(--border); border-radius:10px; font:inherit; }
.practice-task-tabs { display:flex; flex-wrap:wrap; gap:8px; margin:18px 0; }
.practice-task-tab { border:1px solid #d7e6d8; background:#fff; color:#286f31; padding:9px 14px; border-radius:10px; cursor:pointer; font-weight:700; }
.practice-task-tab.active { background:#32883b; color:#fff; }
.practice-task-panel { display:none; }
.practice-task-panel.active { display:block; }
.practice-task-panel .editor { margin-top:14px; }
.task { padding:18px; margin-bottom:12px; border:1px solid var(--border); border-radius:14px; background:#fff; }
.task.completed { border-color:#8acb92; background:#f3fbf4; }
.teacher-main, .container { background:transparent; }


/* Практика: широкая рабочая область для редактора и заданий */
body.practice-page .container {
    width: min(1440px, calc(100% - 48px));
    max-width: 1440px;
    margin-left: auto;
    margin-right: auto;
}
body.practice-page .practice-layout {
    display: block;
    width: 100%;
}
body.practice-page .tasks {
    width: 100%;
    box-sizing: border-box;
    padding: clamp(20px, 3vw, 36px);
}
body.practice-page .practice-task-panel .task {
    padding: clamp(18px, 2.5vw, 30px);
}
body.practice-page .editor textarea.task-code {
    width: 100%;
    min-height: 280px;
    box-sizing: border-box;
}
/* Один и тот же бирюзово-зелёный оттенок, что и у кнопки на стартовой странице. */
:root {
    --primary: #00897B;
    --primary-dark: #00695C;
    --primary-light: #26A69A;
}
.btn, .btn-check, .btn-start, .btn-finish, .sidebar-link.active,
.topbar, .login-box button, .practice-task-tab.active {
    background: #00897B !important;
}
.btn:hover, .btn-check:hover, .btn-start:hover, .btn-finish:hover,
.login-box button:hover, .sidebar-link.active:hover, .practice-task-tab.active:hover {
    background: #00695C !important;
}
.topbar { background: linear-gradient(110deg, #00897B, #00695C) !important; }
@media (max-width: 700px) {
    body.practice-page .container { width: calc(100% - 24px); }
    body.practice-page .tasks { padding: 16px; }
}


/* Статусы вкладок практических заданий — мягкие цвета без резкого контраста */
.practice-task-tab {
    background: #ffffff !important;
    color: #344054 !important;
    border: 1px solid #d9dee7 !important;
    transition: background-color .18s ease, border-color .18s ease, box-shadow .18s ease;
}
.practice-task-tab.task-tab-correct {
    background: #dff3e4 !important;
    border-color: #a8d9b5 !important;
    color: #245b34 !important;
}
.practice-task-tab.task-tab-incorrect {
    background: #fde7e7 !important;
    border-color: #f2b8b8 !important;
    color: #8f3030 !important;
}
/* Активность вкладки обозначаем только контуром: фон отражает результат проверки. */
.practice-task-tab.active {
    background: #ffffff !important;
    color: #344054 !important;
    box-shadow: 0 0 0 2px rgba(0, 137, 123, .28) !important;
    outline: none;
}
.practice-task-tab.task-tab-correct.active {
    background: #dff3e4 !important;
    border-color: #a8d9b5 !important;
    color: #245b34 !important;
}
.practice-task-tab.task-tab-incorrect.active {
    background: #fde7e7 !important;
    border-color: #f2b8b8 !important;
    color: #8f3030 !important;
}
.practice-task-tab:hover {
    filter: brightness(.98);
}

/* ---------- Обновлённая шапка: аккуратный акцент без смены общей темы ---------- */
.topbar {
    min-height: 68px;
    padding: 12px clamp(18px, 3vw, 36px);
    gap: 18px;
    background: linear-gradient(112deg, hsl(173, 66%, 8%) 0%, hsl(172, 11%, 14%) 58%, hwb(219 4% 69%) 100%) !important;
    border-bottom: 3px solid rgba(255, 255, 255, .22);
    box-shadow: 0 5px 18px rgba(0, 105, 92, .16);
}
.topbar::after {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    bottom: -3px;
    height: 1px;
    background: rgba(255, 255, 255, .35);
    pointer-events: none;
}
.topbar > span,
.topbar-user > span {
    color: #fff;
    font-weight: 650;
    letter-spacing: .01em;

}
.topbar-user {
    display: flex;
    align-items: center;
    gap: 11px;
    min-width: 0;
    padding: 5px 12px 5px 5px;
    border-radius: 14px;
    
}
.topbar-user img {
    border: 2px solid rgba(255, 255, 255, .78);
    box-shadow: 0 2px 8px rgba(0, 0, 0, .13);
}
.topbar-user small {
    display: inline-block;
    margin-left: 4px;
    color: rgba(255, 255, 255, .76);
    font-size: .82em;
    font-weight: 500;
}
.topbar a {
    margin-left: 0;
    padding: 9px 14px;
    border: 1px solid rgba(255, 255, 255, .18);
    border-radius: 10px;
    font-weight: 600;
    white-space: nowrap;
    transition: background .18s ease, border-color .18s ease, transform .18s ease;
}
.topbar a:hover {
    background: rgba(255, 255, 255, .15);
    border-color: rgba(255, 255, 255, .36);
    transform: translateY(-1px);
}
.topbar a:focus-visible {
    outline: 2px solid #d7fff7;
    outline-offset: 3px;
}
@media (max-width: 700px) {
    .topbar {
        min-height: 60px;
        padding: 10px 14px;
        gap: 8px;
    }
    .topbar-user { gap: 8px; padding-right: 8px; border-radius: 11px; }
    .topbar-user > span { font-size: .9rem; }
    .topbar a { padding: 8px 10px; font-size: .88rem; }
}


/* ---------- Кнопка плавного возврата наверх ---------- */
.back-to-top {
    position: fixed;
    right: 26px;
    bottom: 26px;
    z-index: 120;
    display: grid;
    place-items: center;
    width: 52px;
    height: 52px;
    padding: 0;
    border: 1px solid rgba(255, 255, 255, .35);
    border-radius: 50%;
    background: linear-gradient(135deg, #00897b, #00695c);
    color: #fff;
    font: inherit;
    font-size: 27px;
    line-height: 1;
    cursor: pointer;
    box-shadow: 0 8px 24px rgba(0, 105, 92, .28);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(10px);
    transition: opacity .22s ease, transform .22s ease, visibility .22s ease, box-shadow .18s ease;
}
.back-to-top.is-visible {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateY(0);
}
.back-to-top:hover {
    box-shadow: 0 10px 28px rgba(0, 105, 92, .38);
    transform: translateY(-3px);
}
.back-to-top:focus-visible {
    outline: 3px solid #80cbc4;
    outline-offset: 4px;
}
@media (max-width: 640px) {
    .back-to-top { right: 16px; bottom: 16px; width: 46px; height: 46px; font-size: 24px; }
}
@media (prefers-reduced-motion: reduce) {
    .back-to-top { transition: none; }
}

/* Изображения, добавленные преподавателем в теорию */
.theory-image { margin: 22px auto; text-align: center; }
.theory-image img { display: inline-block; max-width: 100%; height: auto; max-height: 720px; object-fit: contain; border-radius: 12px; border: 1px solid var(--border); box-shadow: var(--shadow-sm); }

/* Muted red style for removing a participant from a group chat */
.messages-page .members-modal .member-actions .remove-member-form button.msg-btn.remove-member-btn,
.messages-page .members-modal .member-actions button.remove-member-btn {
    background: #d98b8b !important;
    background-image: none !important;
    border-color: #d98b8b !important;
    color: #ffffff !important;
    box-shadow: none !important;
}
.messages-page .members-modal .member-actions .remove-member-form button.msg-btn.remove-member-btn:hover,
.messages-page .members-modal .member-actions button.remove-member-btn:hover {
    background: #c87575 !important;
    background-image: none !important;
    border-color: #c87575 !important;
    color: #ffffff !important;
}
.topbar {
    background: hwb(172 15% 65%) !important;
    background-image: none !important;
    border-bottom: none !important;
    box-shadow: 0 5px 18px rgba(52, 50, 61, 0.16) !important;
}

.topbar::before,
.topbar::after {
    display: none !important;
    content: none !important;
}
.topbar a[href*="logout"],
.topbar a[href*="logout"]:hover,
.topbar a[href*="logout"]:focus,
.topbar a[href*="logout"]:active {
    border: none !important;
    outline: none !important;
    box-shadow: none !important;
}
.topbar .username,
.topbar .profile,
.topbar .user-name,
.topbar .user-info,
.topbar a[href*="profile"],
.topbar a[href*="account"] {
    border: none !important;
    outline: none !important;
    box-shadow: none !important;
}

/* Убираем обводку при фокусе и наведении */
.topbar .username:hover,
.topbar .username:focus,
.topbar .username:active,
.topbar .profile:hover,
.topbar .profile:focus,
.topbar .profile:active {
    border: none !important;
    outline: none !important;
    box-shadow: none !important;
}