* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    user-select: none;
}

html,
body {
    width: 100vw;
    height: 100vh;
}

.main {
    width: 100%;
    height: 100%;
    background: url(../images/bg2.png) no-repeat 100% 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    position: relative;
}

    .main .exit-btn {
        position: absolute;
        top: 20px;
        right: 20px;
        font-size: 20px;
        width: 80px;
        height: 40px;
        text-align: center;
        line-height: 40px;
        color: #ffffff;
        background: #8391bd;
        border-radius: 8px;
        cursor: pointer;
    }

    .main .login2-btn {
        position: absolute;
        top: 20px;
        right: 20px;
        font-size: 20px;
        width: 80px;
        height: 40px;
        text-align: center;
        line-height: 40px;
        color: #ffffff;
        background: #328CD1;
        border-radius: 8px;
        cursor: pointer;
    }

    .main .top-mark {
        font-size: 18px;
        color: #fff;
        font-weight: bold;
        line-height: 80px;
    }

    .main .subject-items {
        display: grid;
        grid-template-columns: repeat(2, 440px);
        grid-template-rows: repeat(2, 228px);
        column-gap: 30px;
        row-gap: 30px;
    }

        .main .subject-items .subject-item {
            width: 100%;
            height: 100%;
            border-radius: 20px;
            display: flex;
            flex-direction: column;
            justify-content: space-between;
            align-items: start;
            padding: 40px;
            background-position: 80% center;
            background-repeat: no-repeat;
            background-size: auto 80%, 100% 100%;
            position: relative;
        }

            .main .subject-items .subject-item .title {
                font-size: 30px;
                font-weight: bold;
                color: #fff;
                text-shadow: 2px 2px 2px rgba(0, 0, 0, 0.5);
            }

            .main .subject-items .subject-item .btn {
                height: 40px;
                line-height: 38px;
                width: 124px;
                text-align: center;
                border-radius: 20px;
                font-size: 20px;
                font-weight: bold;
                color: #fff;
                border: 1px solid #fff;
            }

            .main .subject-items .subject-item.eng {
                background-image: url(../images/eng-icon.png), linear-gradient(45deg, #527BFD 10%, #9ECCFF 90%);
            }

                .main .subject-items .subject-item.eng .btn {
                    background-image: linear-gradient(0deg, #4440FF 10%, #03A5FD 90%);
                }

            /* .main .subject-items .subject-item.eng::after {
    content: "";
    width: 25px;
    height: 50px;
    border-radius: 0 25px 25px 0;
    position: absolute;
    background-color: #fff;
    background-image: linear-gradient(45deg, #adc4fb, #a7bcfb);
    right: -25px;
    top: calc(50% - 25px);
} */

            .main .subject-items .subject-item.math {
                background-image: url(../images/math-icon.png), linear-gradient(45deg, #2BE8B5 10%, #6EF7D6 90%)
            }



                .main .subject-items .subject-item.math .btn {
                    background-image: linear-gradient(0deg, #3DBA81 10%, #AFFFEB 90%);
                }

            /* 
.main .subject-items .subject-item.math::before {
    content: "";
    width: 25px;
    height: 50px;
    border-radius: 0 25px 25px 0;
    position: absolute;
    background-color: #fff;
    left: 0;
    top: calc(50% - 25px);
} */

            .main .subject-items .subject-item.physics {
                background-image: url(../images/physics-icon.png), linear-gradient(45deg, #36A5FA 10%, #A0E7FF 90%)
            }

                .main .subject-items .subject-item.physics .btn {
                    background-image: linear-gradient(0deg, #328CD1 10%, #A2E5FE 90%);
                }

            .main .subject-items .subject-item.chemistry {
                background-image: url(../images/chemistry-icon.png), linear-gradient(45deg, #9598FF 10%, #BDD0FF 90%)
            }

                .main .subject-items .subject-item.chemistry .btn {
                    background-image: linear-gradient(0deg, #4854D5 10%, #B6C9FF 90%);
                }


    .main .login-box {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        display: none;
        justify-content: center;
        align-items: center;
    }

        .main .login-box.show {
            display: flex;
        }

        .main .login-box .login-form {
            width: 400px;
            height: 300px;
            border-radius: 10px;
            background-color: #fff;
            background-image: url(../images/plane.png);
            background-position: 10px 10px;
            background-repeat: no-repeat;
            background-size: 70px auto;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            position: relative;
            z-index: 11;
        }

            .main .login-box .login-form .close-btn {
                --size: 20px;
                background: url(../images/mask_close.png) no-repeat;
                background-size: 100% 100%;
                height: var(--size);
                width: var(--size);
                position: absolute;
                right: 20px;
                top: 20px;
            }

            .main .login-box .login-form .title {
                height: 30px;
                line-height: 30px;
                font-size: 24px;
                margin-bottom: 20px;
            }

            .main .login-box .login-form .input-item {
                --border-color: #ccc;
                width: 260px;
                height: 40px;
                display: flex;
                align-items: center;
                margin-bottom: 25px;
                position: relative;
            }

                .main .login-box .login-form .input-item .label {
                    display: inline-block;
                    text-align: center;
                    width: 60px;
                    line-height: 40px;
                    font-size: 14px;
                    border: 1px solid var(--border-color);
                    height: 40px;
                    border-radius: 8px 0 0 8px;
                }

                .main .login-box .login-form .input-item .input {
                    border: 1px solid var(--border-color);
                    border-left: none;
                    flex: 1;
                    padding: 5px 10px;
                    height: 40px;
                    border-radius: 0 8px 8px 0;
                }

                .main .login-box .login-form .input-item .error {
                    position: absolute;
                    left: 70px;
                    color: #ff0000;
                    top: 40px;
                    height: 20px;
                    line-height: 20px;
                    font-size: 12px;
                    display: none;
                }

                    .main .login-box .login-form .input-item .error.show {
                        display: block;
                    }

                .main .login-box .login-form .input-item input:visited,
                .main .login-box .login-form .input-item input:focus-visible {
                    outline: none;
                }

            .main .login-box .login-form .login-btn {
                width: 260px;
                height: 40px;
                text-align: center;
                line-height: 40px;
                border-radius: 8px;
                background-color: #45b5f1;
                color: #fff;
                cursor: pointer;
            }