:root {
    --primary: #007aff;
    --bg-light: #f2f2f7;
    --bg-card: #ffffff;
    --text-main: #1c1c1e;
    --text-muted: #8e8e93;
    --border: #e5e5ea;
    --radius: 14px;
}

/* Автоматическая поддержка тёмной темы */
@media (prefers-color-scheme: dark) {
    :root {
        --primary: #0a84ff;
        --bg-light: #000000;
        --bg-card: #1c1c1e;
        --text-main: #f2f2f7;
        --text-muted: #8e8e93;
        --border: #2c2c2e;
    }
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-light);
    color: var(--text-main);
    line-height: 1.6;
    padding: 20px 16px;
    max-width: 720px;
    margin: 0 auto;
    -webkit-font-smoothing: antialiased;
}

/* Шапка приложения */
.app-header {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px 20px;
    margin-bottom: 20px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    align-items: center;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.03);
}

@media (min-width: 480px) {
    .app-header {
        flex-direction: row;
        justify-content: space-between;
    }
}

.app-title {
    font-size: 1.4rem;
    font-weight: 700;
    letter-spacing: -0.4px;
}

/* Переключатель вкладок */
.nav-tabs {
    display: flex;
    background: var(--bg-light);
    padding: 3px;
    border-radius: 9px;
    gap: 2px;
}

.nav-link {
    background: transparent;
    border: none;
    padding: 7px 14px;
    border-radius: 7px;
    color: var(--text-muted);
    font-family: inherit;
    font-weight: 500;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
    text-decoration: none;
    display: inline-block;
}

.nav-link.active {
    background: var(--bg-card);
    color: var(--text-main);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.12);
    font-weight: 600;
}

/* Карточка с контентом */
.content-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 24px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.03);
}

.content-card h1 {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.3px;
    margin-bottom: 16px;
}

.content-card h2 {
    font-size: 1rem;
    font-weight: 600;
    margin-top: 28px;
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-main);
}

.content-card p {
    margin-bottom: 14px;
    color: var(--text-main);
    font-size: 0.95rem;
}

.content-card ul {
    padding-left: 20px;
    margin-bottom: 16px;
}

.content-card li {
    margin-bottom: 8px;
    font-size: 0.95rem;
}

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

.content-card a:hover {
    text-decoration: underline;
}

.content-card em {
    color: var(--text-muted);
    font-style: normal;
    font-size: 0.9rem;
}