body {
    background: linear-gradient(135deg, #f4fcff5e 0%, #aa96bd61 100%);
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.card {
    border: none;
    border-radius: 15px;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
    overflow: hidden;
}

.card-header {
    background-color: #fff;
    border-bottom: none;
    padding-top: 2rem;
    text-align: center;
}

.form-control:focus {
    box-shadow: none;
    border-color: #764ba2;
}

.input-group-text {
    background-color: #f8f9fa;
    border-right: none;
}

.form-control {
    border-left: none;
}

.btn-primary {
    background-color: #764ba2;
    border: none;
    padding: 10px;
    font-size: 1.1rem;
    transition: background 0.3s;
}

.btn-primary:hover {
    background-color: #5b3a7d;
}

.toggle-link {
    cursor: pointer;
    color: #764ba2;
    text-decoration: none;
    font-weight: bold;
}

.toggle-link:hover {
    text-decoration: underline;
}

/* 隱藏註冊時才需要的欄位 (初始狀態) */
.register-only {
    max-height: 37px;
    display: none;
}

#togglePassword i {
    width: 25px;
}