bitforum-frontend/app/(auth)/register/style.scss

#registForm {
    width: 100%;

    fieldset {
        position: relative;
        border: 1px solid #cecece;
        border-radius: 3px;
        padding: 20px 26px;
        align-content: center;
        max-width: 800px;
        margin: 0 auto;

        > legend {
            position: absolute;
            top: -0.625rem;
            left: 1.25rem;
            padding: 0 5px;
            background: white;
            font-size: 1rem;
            font-weight: bold;
        }

        // 좌측 안내문구
        dl {
            dt {
                font-weight: bold;
                padding-bottom: 5px;
            }

            dd {
                font-size: 0.938rem;
            }
        }

        // 회원가입 창
        form {
            label {
                cursor: pointer;
                margin-bottom: 7px;
            }

            input[type="email"],
            input[type="password"] {
                margin-bottom: 15px;
            }

            input[type="password"] {
                letter-spacing: 1px;

                &:last-child {
                    margin-bottom: 0;
                }
            }

            p {
                padding-bottom: 5px;
            }

            section {
                &:nth-of-type(2n+1) {
                    flex-basis: 57%;
                }

                &:nth-of-type(2n) {
                    flex-basis: 43%;

                    label {
                        small {
                            padding-right: 5px;
                        }

                        button {
                            color: #0060a9;

                            &:hover {
                                text-decoration: underline;
                                color: #c7511f;
                            }
                        }
                    }
                }
            }
        }

        hr {
            margin: 20px 0;
        }
    }
}

@media (max-width: 660px) {
    #registForm {
        fieldset {
            form {
                section {

                    &:nth-of-type(2n+1) {
                        flex-basis: 100%;
                    }
    
                    &:nth-of-type(2n) {
                        flex-basis: 100%;
                    }
                }
            }
        }
    }
}