:root {
    --primary: #1e4b69;
    --accent: rgb(70, 180, 200);
    --bg: #f5f7fa;
    --circle-a: rgba(41, 128, 185, 0.35);
    --circle-b: rgba(39, 174, 96, 0.35);
    --highlight: rgba(241, 196, 15, 0.6);
}

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

body {
    font-family: 'Segoe UI', system-ui, sans-serif;
    background: var(--bg);
    color: #333;
    padding: 20px;
    display: flex;
    justify-content: center;
}

.container {
    max-width: 960px;
    width: 100%;
}

h1 {
    color: var(--primary);
    text-align: center;
    font-size: 1.6rem;
    margin-bottom: 4px;
}

.subtitle {
    text-align: center;
    color: #666;
    margin-bottom: 20px;
    font-size: 0.95rem;
}

.join-tabs {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.join-tab {
    padding: 10px 20px;
    border: 2px solid var(--primary);
    border-radius: 8px;
    background: white;
    color: var(--primary);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.25s;
    font-size: 0.9rem;
}

.join-tab:hover {
    background: var(--primary);
    color: white;
}

.join-tab.active {
    background: var(--primary);
    color: white;
    box-shadow: 0 2px 8px rgba(30, 75, 105, 0.3);
}

.content-area {
    display: flex;
    gap: 24px;
    background: white;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
}

.venn-panel {
    flex: 0 0 380px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

#venn-svg {
    width: 100%;
    max-width: 380px;
}

.venn-labels {
    display: flex;
    justify-content: space-between;
    width: 100%;
    max-width: 340px;
    margin-top: 6px;
}

.venn-labels span {
    font-size: 0.8rem;
    font-weight: 600;
}

.label-a {
    color: #2980b9;
}

.label-b {
    color: #27ae60;
}

.info-panel {
    flex: 1;
    min-width: 0;
}

.info-panel h3 {
    color: var(--primary);
    margin-bottom: 8px;
    font-size: 1rem;
}

.sql-section {
    margin-bottom: 16px;
}

pre {
    background: #1e1e2e;
    color: #cdd6f4;
    padding: 14px;
    border-radius: 8px;
    font-size: 0.82rem;
    overflow-x: auto;
    line-height: 1.5;
}

.data-section {
    margin-bottom: 16px;
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.85rem;
}

th {
    background: var(--primary);
    color: white;
    padding: 8px 10px;
    text-align: left;
    font-weight: 600;
}

td {
    padding: 7px 10px;
    border-bottom: 1px solid #eee;
}

tr:nth-child(even) {
    background: #f8f9fa;
}

td.null-value {
    color: #bbb;
    font-style: italic;
}

.description {
    color: #555;
    font-size: 0.9rem;
    line-height: 1.5;
    padding: 12px;
    background: #f0f7ff;
    border-radius: 8px;
    border-left: 4px solid var(--accent);
}

@media (max-width: 780px) {
    .content-area {
        flex-direction: column;
        padding: 20px;
    }

    .venn-panel {
        flex: none;
    }
}