/* 共通スタイル（スマホファースト） */
body {
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', sans-serif;
    background-color: #e5ddd5;
    font-size: 16px;
}

.logo {
    font-size: 36px;
    text-align: center;
    color: #075e54;
    margin-top: 30px;
}

.container,
.login-box,
.register-box,
.chat-container,
.chat-form {
    width: 90%;
    max-width: 600px;
    margin: auto;
    padding: 20px;
    box-sizing: border-box;
}

/* 入力フォーム系 */
input[type="text"],
input[type="password"],
input[type="file"],
input[type="email"],
select,
textarea {
    width: 100%;
    padding: 12px;
    margin: 10px 0;
    border: 1px solid #ccc;
    border-radius: 10px;
    font-size: 16px;
}

button {
    width: 100%;
    padding: 14px;
    background-color: #25d366;
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 18px;
    font-weight: bold;
}

/* エラーや通知 */
.error {
    color: red;
    font-size: 14px;
    margin-top: 10px;
    text-align: center;
}

/* チャット部分 */
.chat-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 80px;
    overflow-y: auto;
    max-height: 70vh;
}

.message {
    padding: 12px;
    border-radius: 15px;
    max-width: 80%;
    word-wrap: break-word;
    font-size: 16px;
    position: relative;
    line-height: 1.4;
}

.message.self {
    background-color: #dcf8c6;
    align-self: flex-end;
    text-align: right;
}

.message.other {
    background-color: #ffffff;
    align-self: flex-start;
}

.username {
    font-weight: bold;
    font-size: 14px;
    color: #075e54;
    margin-bottom: 4px;
}

.timestamp {
    font-size: 12px;
    color: gray;
    margin-top: 6px;
}

/* フォームの位置 */
.chat-form {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background-color: white;
    padding: 12px;
    box-shadow: 0 -2px 5px rgba(0, 0, 0, 0.1);
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 100;
}

/* レスポンシブ調整 */
@media (min-width: 768px) {
    body {
        font-size: 18px;
    }

    .message {
        font-size: 18px;
    }

    .username {
        font-size: 16px;
    }

    .timestamp {
        font-size: 14px;
    }

    button {
        font-size: 20px;
    }
}