body {
    font-family: 'Segoe UI', Tahoma, sans-serif;
    margin: 0;
    padding: 0;
    text-align: center;
    background: linear-gradient(135deg, #667eea, #764ba2);
    height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: white;
    user-select: none;
}

h1 {
    text-shadow: 2px 2px 8px rgba(0,0,0,0.4);
    margin-bottom: 10px;
    user-select: none;
}

p {
    font-size: 18px;
    margin-bottom: 15px;
    user-select: none;
}

input {
    padding: 10px;
    font-size: 16px;
    border-radius: 8px;
    border: none;
    outline: none;
    width: 120px;
    text-align: center;
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
    margin-bottom: 12px;
    user-select: none;
}

button {
    padding: 10px 20px;
    font-size: 16px;
    font-weight: bold;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    background: linear-gradient(90deg, #ff6a00, #ee0979);
    color: white;
    box-shadow: 0 4px 15px rgba(0,0,0,0.3);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    user-select: none;
}

button:hover {
    transform: scale(1.05);
    box-shadow: 0 6px 20px rgba(0,0,0,0.4);
    user-select: none;
}

#message {
    margin-top: 20px;
    font-size: 22px;
    font-weight: bold;
    text-shadow: 1px 1px 4px rgba(0,0,0,0.3);
    user-select: none;
}

.low { color: #ffd700; }
.high { color: #ff6347; }
.correct { color: #32cd32; animation: pop 0.5s ease forwards; }

@keyframes pop {
    0% { transform: scale(1); }
    50% { transform: scale(1.3); }
    100% { transform: scale(1); }
}

.controls {
    margin-top: 25px;
    user-select: none;
}

.back-btn {
    display: inline-block;
    text-decoration: none;
    padding: 10px 18px;
    border-radius: 10px;
    background: rgba(255,255,255,0.9);
    color: #3a3a3a;
    box-shadow: 0 6px 18px rgba(0,0,0,0.15);
    font-weight: bold;
    transition: transform 0.15s ease, box-shadow 0.15s ease;
    user-select: none;
}

.back-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 24px rgba(0,0,0,0.18);
    user-select: none;
}