body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: #f4f4f9;
    color: #333;
    margin: 0;
    padding-top: 70px; /* ヘッダーの高さ分 */
}

header {
    background-color: #007bff;
    color: white;
    padding: 15px 0;
    text-align: center;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
    z-index: 1000;
}

header h1 {
    margin: 0;
    font-size: 22px;
}

main {
    display: flex;
    justify-content: center;
    padding: 20px 10px;
}

#setup-screen, #timer-screen {
    background-color: #fff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 500px;
    box-sizing: border-box;
}

h1, h2 {
    text-align: center;
    color: #444;
}

.input-group, .display-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: bold;
    color: #555;
}

select, textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 5px;
    box-sizing: border-box;
    font-size: 16px;
    background-color: white;
}

textarea {
    resize: vertical;
}

button {
    width: 100%;
    padding: 15px;
    background-color: #007bff;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 18px;
    font-weight: bold;
    cursor: pointer;
    transition: background-color 0.3s;
}

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

#timer-display {
    font-size: clamp(48px, 20vw, 72px);
    font-weight: bold;
    text-align: center;
    margin-bottom: 20px;
    color: #333;
}

#notification-area {
    text-align: center;
    font-size: 18px;
    font-weight: bold;
    color: #d9534f;
    min-height: 27px;
    margin-bottom: 20px;
}

.display-group {
    background-color: #f9f9f9;
    padding: 15px;
    border-radius: 5px;
    border: 1px solid #eee;
}

.display-group h2 {
    margin-top: 0;
    margin-bottom: 10px;
    font-size: 20px;
    border-bottom: 2px solid #007bff;
    padding-bottom: 5px;
}

pre {
    white-space: pre-wrap;
    word-wrap: break-word;
    font-family: inherit;
    font-size: 16px;
    margin: 0;
}

/* スマートフォン向けのスタイル */
@media (max-width: 480px) {
    body {
        padding-top: 60px;
    }

    header {
        padding: 12px 0;
    }

    header h1 {
        font-size: 20px;
    }

    main {
        padding: 10px;
    }

    #setup-screen, #timer-screen {
        padding: 15px;
    }

    button {
        padding: 12px;
        font-size: 16px;
    }

    #notification-area {
        font-size: 16px;
        min-height: 24px;
    }

    .display-group h2 {
        font-size: 18px;
    }

    pre {
        font-size: 14px;
    }
}