body {
    font-family: 'Helvetica Neue', Arial, sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    margin: 0;
    background-color: #f0f2f5;
    color: #333;
    padding: 20px 0;
}

.container {
    text-align: center;
    background: white;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    max-width: 480px;
    width: 95%;
}

h1 {
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: #555;
}

.counter-display {
    font-size: 0.9rem;
    color: #888;
    text-align: right;
    margin-bottom: 15px;
}

.pair-display {
    font-size: 4rem;
    font-weight: bold;
    margin-bottom: 30px;
    letter-spacing: 8px;
    color: #007bff;
    min-height: 6rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.pair-display.error {
    font-size: 1rem;
    color: #dc3545;
    letter-spacing: 0;
    padding: 0 10px;
}

/* メインボタン */
button {
    font-size: 1.2rem;
    padding: 12px 40px;
    background-color: #007bff;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.2s;
    width: 100%;
    margin-bottom: 15px;
}

button:hover { background-color: #0056b3; }

/* プリセットボタン用の横並び設定 */
.scheme-controls {
    display: flex;
    gap: 10px;
    margin: 12px 0 15px 0;
}

.sub-btn {
    font-size: 0.85rem;
    padding: 10px 0;
    margin-bottom: 0;
    flex: 1;
    background-color: #6c757d;
}

.sub-btn:hover { background-color: #5a6268; }

.prev-display {
    font-size: 1rem;
    color: #888;
    min-height: 1.5rem;
    margin-bottom: 20px;
}

.separator {
    border: 0;
    height: 1px;
    background: #e9ecef;
    margin: 20px 0;
}

.settings-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
    margin-bottom: 20px;
    text-align: left;
}

.filter-section label {
    font-size: 0.8rem;
    color: #666;
    display: block;
    margin-bottom: 5px;
}

.filter-section input {
    width: 100%;
    padding: 10px;
    font-size: 1rem;
    border: 1px solid #ccc;
    border-radius: 6px;
    box-sizing: border-box;
}

.scheme-section {
    text-align: left;
    background: #f8f9fa;
    padding: 15px;
    border-radius: 8px;
    border: 1px solid #e9ecef;
}

.scheme-section label {
    font-size: 0.8rem;
    font-weight: bold;
    color: #495057;
    display: block;
    margin-bottom: 6px;
}

.scheme-section input {
    width: 100%;
    padding: 10px;
    font-size: 1.1rem;
    letter-spacing: 2px;
    border: 1px solid #ced4da;
    border-radius: 6px;
    box-sizing: border-box;
}

.scheme-guide {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 6px;
    font-size: 0.75rem;
    color: #6c757d;
    text-align: center;
}

.guide-item {
    background: white;
    padding: 4px;
    border: 1px solid #e9ecef;
    border-radius: 4px;
}

.sticker-name { font-weight: bold; }
.sticker-char { color: #007bff; font-weight: bold; }