html {
    background-color: #eee8e8;
margin: -10px;
}
body {
display: flex;
/*flex-basis: 100%;*/
height: 100%;
justify-content: center;
}
.container {
    display: flex;
    flex-direction: column;
    width: 100%;
    max-width: 1024px;
    height: 100%;
    justify-content: space-between;
    background-color: green;
}
.header {
    display: flex;
    flex-direction: column;
    flex-basis: 20%;
    background-color: #58C;
    height: 8em;
}
.title {
    display: flex;
    flex-direction: row;
    justify-content: space-between;
    align-items: flex-end;

}
.level {
    display: flex;
    width: 14rem;
    /*background-color: gold;*/
    justify-content: space-between;
    align-items: flex-end;
}

.tab {
    height: 2rem;
    width: 2rem;
    margin-bottom: 0.3rem;
    text-align: center;
    padding-top: 0.5rem;
}
.tab-curent {
   width: 3rem;
    height: 2rem;
    
    text-align: center;
    padding-top: 0.5rem;

}
.a0 {
    background-color: green;
}
.a1 {
    background-color: orange;
}
.a2 {
    background-color: blue;
}
.b1 {
    background-color: purple;
}
.b2 {
    background-color: violet;
}
.c1 {
    background-color: darkorange;
}
.sp-title {
    display: block;
    text-align: center;
    padding: 0.5rem;
    /*color: #3c3c6a;*/
    color: #000;

    font-family: Comic Sans MS, cursive;
    font-size: 2rem;

}
.lang {
    width: 5rem;
    height: 1.5rem;
    flex-direction: row;
    display: flex;
    padding: 0.3rem;
    justify-content: space-between;
}
.ua {
    display: flex;
    opacity: 0.3;
    flex-direction: column;
    flex-basis: 45%;
    background-color: yellow;
}
.ua:hover {
    opacity: 1;
    cursor: pointer;
}
.up {
    flex-basis: 50%;
    background-color: blue;
}
.ru {
    display: flex;
    opacity: 0.3;
    flex-direction: column;
    flex-basis: 45%;
    background-color: blue;
}
.ru:hover {
    opacity: 1;
    cursor: pointer;
}
.active {
    opacity: 1;
}
.r_up {
    flex-basis: 33%;
    background-color: white;
}
.r_center {
    flex-basis: 33%;
}
.r_dw {
    flex-basis: 33%;
    background-color: red;
}
.body {
    display: flex;
    flex-direction: column;
    margin-top: 1rem;
    flex-basis: 80%;
}
.menu {
    display: flex;
    flex-basis: 100%;
    flex-direction: row;
    justify-content: center;
    padding: 0.3rem;
    background-color: #212;
}
.menu ul {
    display: flex;
    flex-basis: 50%;
    justify-content: space-between;
    font-size: 1.5rem;
}
.menu-button {
    /*background-color: darkcyan;*/
    background-color: #124;
    color: #5588ff;
    padding: 0.4em;
    margin: 1px;
    /*border: none;*/
    cursor: pointer;
    width: 7rem;
    border-radius: 1em;
}
.menu-button:hover {
    color: #3f3;
}
.nav {
    background-color: #69D;
    padding: 0.5rem;
}
.nav button {
    cursor: pointer;
}
H1 {
    text-align: center;
    color: #bbe6e6; ;
    font-size: 1.2rem;
    /*background-color: #5c9;*/
}
.info {
    color: #fefefe ;
    margin: 1rem;
}
.out-text {
    margin: 1rem;
    /*flex-basis: 800px;*/
    background-color: #ddd;
    border-radius: 1rem;
}
.out-title {
    display: flex;
    flex-wrap: nowrap;
    padding: 1rem;
    /*background-color: #acd;*/
    background-color: #8cf;
    width: auto;
    font-size: 1.5rem;
    border-radius: 1rem 1rem 0 0;
}
.out-title-flex-left {}
.out-title-flex-center {
    flex-basis: 80%;
}
.out-title-flex-right {}
.number {
    margin: 0.5rem;
}
.out-text H3 {
    text-align: center;
    font-size: 1.5rem;
}
.li-out {
    margin: 1em;
    font: 1rem sans-serif;
}


#sel {
    font-size: 1.5rem;
    background-color: #58c;
}
.bt-success {
    background-color: #5c9;
}
#h3-lesson {}
.success {
    /* background-color: aquamarine;*/
    border-color: aquamarine;
}

.hide {
    visibility: hidden;
}
.footer{
    display: flex;
    /*flex-basis: 100%;*/
    height: 20rem;
    color: white;
    background-color: #222;
    flex-basis: 10%;
    margin-top: 1rem;
}
.font-xl{
    font-size: 1.9rem;
    margin-left: 5%;
    width: 90%;
}

.error {
    /*background-color:red ;*/
    border-style: solid;
    border-color: red;
}