/* Базовые стили */

*,
*::before,
*::after {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
    height: 100%;
}

body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background: #f3f4f6;
    color: #111827;
}

/* Контейнер страницы */

.page {
    min-height: 100vh;
    display: flex;
    align-items: stretch;
    justify-content: center;
    padding: 24px;
}

.page-card {
    display: flex;
    width: 100%;
    max-width: 1180px;
    background: #ffffff;
    border-radius: 18px;
    box-shadow: 0 18px 50px rgba(15, 23, 42, 0.12);
    overflow: hidden;
}

/* Сайдбар слева */

.sidebar {
    width: 260px;
    min-width: 220px;
    background: linear-gradient(180deg, #f9fafb 0%, #f3f4f6 100%);
    border-right: 1px solid rgba(148, 163, 184, 0.5);
    padding: 24px 20px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.sidebar-title {
    font-size: 1.3rem;
    margin: 0;
    line-height: 1.3;
}

.sidebar-subtitle {
    margin: 4px 0 0;
    font-size: 0.85rem;
    color: #6b7280;
}

/* Кнопки вкладок */

.tab-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: 12px;
}

.tab-button {
    border: none;
    text-align: left;
    padding: 10px 12px;
    border-radius: 10px;
    background: transparent;
    color: #4b5563;
    font-size: 0.95rem;
    cursor: pointer;
    transition: background-color 0.18s ease, color 0.18s ease, transform 0.08s ease;
}

.tab-button:hover {
    background-color: rgba(59, 130, 246, 0.08);
    color: #111827;
    transform: translateX(1px);
}

.tab-button--active {
    background: linear-gradient(90deg, #009dcc, #26dae6);
    color: #ffffff;
}

/* Подпись под вкладками */

.sidebar-note {
    margin-top: auto;
    padding: 12px 10px;
    border-radius: 12px;
    background: rgba(59, 130, 246, 0.07);
    border: 1px dashed rgba(59, 130, 246, 0.5);
    font-size: 0.8rem;
    color: #374151;
}

/* Основной контент справа */

.content-area {
    flex: 1;
    padding: 24px 28px;
    display: flex;
    flex-direction: column;
    gap: 24px;
    background: radial-gradient(circle at top right, rgba(129, 140, 248, 0.12), transparent 55%);
}

/* Секции техник */

.tech-content {
    display: none;
    flex-direction: column;
    gap: 18px;
}

.tech-content--active {
    display: flex;
}

/* Заголовок техники */

.tech-header h2 {
    margin: 0 0 6px;
    font-size: 1.4rem;
}

.tech-tagline {
    margin: 0;
    font-size: 0.9rem;
    color: #6b7280;
}

/* Текстовое описание */

.tech-text h3 {
    margin: 12px 0 6px;
    font-size: 1.05rem;
}

.tech-text p {
    margin: 0 0 8px;
    font-size: 0.95rem;
}

.tech-text ul {
    margin: 0 0 4px 16px;
    padding-left: 12px;
}

.tech-text li {
    margin-bottom: 4px;
    font-size: 0.95rem;
}

/* Блок с iframe */

.tech-iframe-block {
    margin-top: 12px;
    background: #f9fafb;
    border-radius: 14px;
    border: 1px solid rgba(148, 163, 184, 0.6);
    padding: 12px 12px 10px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.tech-iframe-header {
    font-size: 0.88rem;
    font-weight: 500;
    color: #374151;
    padding: 4px 8px;
    border-radius: 999px;
    align-self: flex-start;
    background: rgba(59, 130, 246, 0.08);
}

/* Сам iframe */

.tech-iframe {
    width: 100%;
    height: 260px;
    border-radius: 12px;
    border: none;
    background: #ffffff;
    box-shadow: inset 0 0 0 1px rgba(148, 163, 184, 0.35);
}

/* Описание выбранного элемента */

.element-description {
    margin-top: 6px;
    padding: 10px 12px;
    border-radius: 10px;
    background: #ffffff;
    border: 1px dashed rgba(156, 163, 175, 0.8);
    font-size: 0.9rem;
    color: #374151;
}

/* Адаптивность */

@media (max-width: 960px) {
    .page {
        padding: 16px;
    }

    .page-card {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid rgba(148, 163, 184, 0.5);
        flex-direction: column;
        gap: 10px;
    }

    .tab-list {
        flex-direction: row;
        overflow-x: auto;
        padding-bottom: 4px;
    }

    .tab-button {
        white-space: nowrap;
        font-size: 0.9rem;
    }

    .sidebar-note {
        margin-top: 8px;
    }

    .content-area {
        padding: 18px 16px 20px;
    }

    .tech-iframe {
        height: 240px;
    }
}

@media (max-width: 600px) {
    .page {
        padding: 10px;
    }

    .sidebar-title {
        font-size: 1.1rem;
    }

    .tech-header h2 {
        font-size: 1.2rem;
    }

    .tech-text p,
    .tech-text li {
        font-size: 0.9rem;
    }

    .tech-iframe {
        height: 220px;
    }
}