:root {
    --bg: #0f1115;
    --panel: #161a22;
    --text: #e6e6eb;
    --muted: #9aa0aa;
    --accent: #4da3ff;
    --border: #262b36;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.container {
    background: var(--panel);
    padding: 24px;
    border-radius: 14px;
    width: 360px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
}

h1 {
    margin: 0 0 16px;
    font-size: 18px;
    font-weight: 600;
}

label {
    font-size: 13px;
    color: var(--muted);
}

input[type="text"],
input[type="number"] {
    width: 100%;
    padding: 10px;
    margin-top: 6px;
    background: #0d1016;
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text);
    outline: none;
}

input:focus {
    border-color: var(--accent);
}

.scale-row {
    display: flex;
    gap: 10px;
    align-items: center;
    margin-top: 14px;
}

input[type="range"] {
    flex: 1;
}

.qr {
    margin-top: 20px;
    display: flex;
    justify-content: center;
}

canvas {
    background: white;
    padding: 8px;
    border-radius: 8px;
}

.hint {
    margin-top: 12px;
    font-size: 12px;
    color: var(--muted);
    text-align: center;
}