/* --- 基本設定 --- */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    margin: 0;
    background: linear-gradient(120deg, #a1c4fd 0%, #c2e9fb 100%);
    color: #333;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
    box-sizing: border-box;
}

/* --- ホームボタン --- */
.home-button {
    position: fixed;
    top: 25px;
    left: 25px;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    border: 2px solid #333;
    border-radius: 50%;
    color: #333;
    background-color: rgba(255, 255, 255, 0.5);
    text-decoration: none;
    transition: all 0.2s ease;
}
.home-button:hover {
    background-color: #333;
    color: #fff;
    transform: scale(1.05);
}
.home-button svg {
    width: 28px;
    height: 28px;
}

/* --- メインコンテナ --- */
.main-container {
    background-color: #ffffff;
    padding: 40px 50px;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    text-align: center;
    max-width: 500px;
    width: 100%;
}

/* --- 入力フォーム --- */
#input-area h1 {
    margin-top: 0;
}
.form-group {
    margin-bottom: 20px;
    text-align: left;
}
.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
}
.form-group input[type="time"] {
    width: 100%;
    padding: 10px;
    font-size: 1.2rem;
    border: 1px solid #ccc;
    border-radius: 8px;
    box-sizing: border-box;
}
#start-button {
    width: 100%;
    padding: 15px;
    font-size: 1.2rem;
    font-weight: bold;
    color: white;
    background-color: #007bff;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s ease;
}
#start-button:hover {
    background-color: #0056b3;
}

/* --- 時刻表示エリア --- */
#display-area {
    padding-top: 20px;
}
.time-display {
    margin-bottom: 20px;
}
.time-label {
    font-size: 1.5rem;
    color: #555;
    margin-bottom: 5px;
}
.clock {
    font-size: 5rem;
    font-weight: bold;
}
.clock-small {
    font-size: 2rem;
    color: #777;
}

/* --- 表示/非表示制御 --- */
.hidden {
    display: none;
}