* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Segoe UI", system-ui, sans-serif;
    background: #0f1117;
    color: #e6e6e6;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.app {
    background: #161a22;
    border-radius: 16px;
    padding: 30px 40px;
    width: 900px;
    max-width: 95%;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.6);
}

header {
    text-align: center;
    margin-bottom: 30px;
}

header h1 {
    margin: 0;
    font-size: 2.4rem;
    color: #ffffff;
}

header p {
    color: #9aa4b2;
    margin-top: 8px;
}

main {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
}

.canvas-box {
    display: flex;
    flex-direction: column;
    align-items: center;
}

canvas {
    background: black;
    border-radius: 12px;
    border: 2px solid #2a2f3a;
    cursor: crosshair;
}

.controls {
    margin-top: 20px;
    display: flex;
    gap: 15px;
}

button {
    background: #2563eb;
    color: white;
    border: none;
    padding: 10px 22px;
    border-radius: 10px;
    font-size: 0.95rem;
    cursor: pointer;
    transition: background 0.2s ease;
}

button:hover {
    background: #1d4ed8;
}

#clear-btn {
    background: #374151;
}

#clear-btn:hover {
    background: #4b5563;
}

.result-box {
    background: #0f1117;
    border-radius: 14px;
    padding: 30px;
    text-align: center;
    border: 1px solid #2a2f3a;
}

.result-box h2 {
    margin-top: 0;
    color: #9aa4b2;
}

#predicted-digit {
    font-size: 5rem;
    margin-top: 20px;
    color: #ffffff;
    font-weight: bold;
}