:root {
    --bg:     #dfe6ef;
    --panel:  #f8fbff;
    --text:   #1f2937;
    --muted:  #5f6f82;
    --line:   #cfd8e3;
    --accent: #3b6ea8;
    --canvas: #1b2430;
}

html, body {
    margin: 0;
    height: 100%;
    background: var(--bg);
    color: var(--text);
    font: 14px/1.4 system-ui, sans-serif;
}

.app {
    display: grid;
    grid-template-columns: 390px 1fr;
    height: 100%;
}

.sidebar {
    background: var(--panel);
    border-right: 1px solid var(--line);
    padding: 16px;
    overflow: auto;
}

.viewer {
    position: relative;
}

canvas {
    width: 100%;
    height: 100%;
    display: block;
    background: var(--canvas);
}

.grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px 12px;
}

label {
    display: block;
    font-size: 12px;
    color: var(--muted);
    margin-bottom: 4px;
}

input {
    width: 100%;
    box-sizing: border-box;
    background: #fff;
    border: 1px solid var(--line);
    color: var(--text);
    border-radius: 8px;
    padding: 8px 10px;
}

.button-stack {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 4px;
}

.button-row {
    display: flex;
    gap: 10px;
}

button {
    background: #2d6fbe;
    color: #fff;
    border: none;
    border-radius: 10px;
    padding: 10px 14px;
    font-weight: 600;
    cursor: pointer;
}

button.secondary {
    background: #6a7e94;
}

.stats,
.notice,
.selection {
    margin-top: 12px;
    padding: 10px;
    border: 1px solid var(--line);
    border-radius: 10px;
    background: #fff;
    color: var(--muted);
    white-space: pre-wrap;
}

h1 {
    margin: 0 0 8px 0;
    font-size: 18px;
}

h2 {
    margin: 18px 0 8px 0;
    font-size: 14px;
    color: var(--accent);
}