body {
    margin: 0;
    overflow: hidden;
    background-color: #0b0f1a;
    font-family: "Segoe UI", "Microsoft YaHei", sans-serif;
}

.node circle {
    fill: #0b0f1a;
    stroke: #38bdf8;
    stroke-width: 2px;
    cursor: pointer;
}

.node text {
    font-size: 18px;
    fill: #e2e8f0;
    pointer-events: none;
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.8);
}

.node-root text {
    font-size: 18px;
    font-weight: bold;
    fill: #60a5fa;
}

.link {
    fill: none;
    stroke: #334155;
    stroke-width: 1.5px;
}

.ui-panel {
    position: fixed;
    top: 20px;
    right: 20px;
    display: flex;
    flex-direction: column;
    gap: 15px;
    z-index: 1000;
    background: rgba(15, 23, 42, 0.9);
    padding: 15px;
    border-radius: 12px;
    border: 1px solid #334155;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
}

.search-box {
    display: flex;
    gap: 8px;
}

#searchInput {
    background: #0f172a;
    border: 1px solid #475569;
    border-radius: 6px;
    padding: 8px 12px;
    color: white;
    outline: none;
    width: 220px;
}

#searchInput:focus { border-color: #38bdf8; }

#mindmap { width: 100vw; height: 100vh; display: block; }

button {
    background: #0284c7;
    color: white;
    border: none;
    padding: 8px 15px;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.2s;
}

button:hover { background: #0ea5e9; }

.button-group {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.button-group button {
    background: #334155;
    flex: 1 1 auto;
    min-width: 80px;
    font-size: 13px;
    padding: 6px 10px;
}