body {
    margin: 0;
    font-family: 'Roboto', sans-serif;
    background: var(--bg);
    color: var(--text);
}

:root {
    --bg: #f3fbff;
    --surface: #ffffff;
    --text: #22303f; /* primary text */
    --muted: #495057; /* paragraph / body text */
    --primary: #2D9CDB;
    --primary-600: #2380c1;
    --accent: #27AE60;
    --border: rgba(34, 48, 63, 0.08);
    --shadow: rgba(34, 48, 63, 0.08);
    --hover-bg: rgba(45, 156, 219, 0.06);
}

.page {
    max-width: 1140px;
    margin: 0 auto;
    padding: 24px;
}

.page-header {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 18px;
    text-align: center;
    padding-bottom: 18px;
    margin-bottom: 18px;
    border-bottom: 1px solid var(--border);
}

.page-title h1 {
    margin: 0;
    font-size: clamp(2rem, 3vw, 3rem);
    line-height: 1.05;
    letter-spacing: -0.03em;
}

.top-nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
}

.nav-link,
.calendar-controls button {
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 10px 18px;
    cursor: pointer;
    font-size: 0.95rem;
    transition: background 0.2s ease, border-color 0.2s ease, color 0.2s ease, transform 0.2s ease;
}

.nav-link:hover,
.calendar-controls button:hover {
    background: var(--hover-bg);
}

.nav-link.active,
.calendar-controls button.active {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

.content-section {
    display: none;
    background: var(--surface);
    border-radius: 18px;
    padding: 30px;
    box-shadow: 0 18px 42px var(--shadow);
    margin-bottom: 24px;
}

.content-section.active {
    display: block;
}

.content-section h2 {
    margin-top: 0;
    margin-bottom: 18px;
    font-size: 1.7rem;
}

.content-section p,
.content-section li {
    line-height: 1.8;
    color: var(--muted);
}

.content-section ul {
    padding-left: 1.2rem;
    margin-top: 12px;
}

.calendar-controls {
    margin-bottom: 24px;
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    align-items: center;
}

.calendar-iframe-container {
    width: 100%;
    overflow: hidden;
    border-radius: 14px;
    margin-top: 8px;
    min-height: 420px;
}

.calendar-iframe-container iframe {
    width: 100%;
    min-height: 650px;
    border: none;
    display: block;
}

.calendar-iframe-container.list-view {
    display: none;
}

h1,
h2,
h3 {
    color: var(--text);
}

a,
a:visited {
    color: var(--accent);
    text-decoration: none;
    font-weight: 600;
}

a:hover {
    color: var(--primary-600);
    text-decoration: underline;
}

.view-btn {
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 10px 18px;
    cursor: pointer;
    font-size: 0.95rem;
    transition: background 0.2s ease, border-color 0.2s ease, color 0.2s ease, transform 0.2s ease;
}

.calendar-controls .view-btn.active {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}

@media (max-width: 900px) {
    .page {
        padding: 18px;
    }

    .content-section {
        padding: 24px;
    }

    .calendar-iframe-container iframe {
        min-height: 560px;
    }
}

@media (max-width: 640px) {
    .page {
        padding: 14px;
    }

    .page-header {
        align-items: stretch;
    }

    .top-nav,
    .calendar-controls {
        justify-content: stretch;
    }

    .nav-link,
    .calendar-controls button {
        width: 100%;
        text-align: center;
    }

    .calendar-iframe-container iframe {
        min-height: 420px;
    }
}