body {
    font-family: 'Segoe UI', 'Malgun Gothic', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #f4f7f9;
    color: #333;
    margin: 0;
}

#app {
    width: 90%;
    max-width: 500px;
    background-color: white;
    padding: 20px 30px;
    border-radius: 16px;
    box-shadow: 0 8px 30px rgba(0,0,0,0.12);
    text-align: center;
}

h1, h2 {
    color: #2c3e50;
}

p {
    color: #7f8c8d;
    line-height: 1.6;
}

.hidden {
    display: none;
}

button {
    background-color: #3498db;
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.3s ease;
    margin-top: 10px;
}

button:hover {
    background-color: #2980b9;
}

#restart-button, #save-score-button {
    background-color: #2ecc71;
}

#restart-button:hover, #save-score-button:hover {
    background-color: #27ae60;
}

input[type="text"] {
    padding: 10px;
    border: 2px solid #ecf0f1;
    border-radius: 8px;
    font-size: 16px;
    margin: 10px 0;
    width: calc(100% - 24px);
}

.game-info {
    display: flex;
    justify-content: space-between;
    font-size: 18px;
    font-weight: bold;
    margin-bottom: 20px;
    color: #34495e;
}

.game-info span#time-info {
    color: #e74c3c;
}

#grid-container {
    display: grid;
    gap: 10px;
    margin-top: 20px;
    /* grid-template-columns will be set by JS */
}

.grid-cell {
    width: 100%;
    padding-bottom: 100%; /* Creates a square aspect ratio */
    border-radius: 8px;
    cursor: pointer;
    transition: transform 0.2s ease;
}

.grid-cell:hover {
    transform: scale(1.05);
}

#ranking {
    margin-top: 30px;
    text-align: left;
}

#ranking-list {
    list-style: none;
    padding: 0;
}

#ranking-list li {
    padding: 8px 12px;
    background-color: #ecf0f1;
    border-radius: 4px;
    margin-bottom: 5px;
}

#ranking-list li:nth-child(odd) {
    background-color: #f9f9f9;
}