body {
    font-family: Segoe, sans-serif;
    font-size: clamp(1rem, 1.5vw, 2rem); 
    margin: 0;                         /* Reset margin (not just top) */
    padding-top: 2px;                /* Replace margin-top for consistency */
    width: 100%;                      
    color: black;
    min-height: 100vh;
    background: linear-gradient(180deg, #f5f9ff 50%, #aec0d2 90%);

}

.header {
    /*width: clamp(19rem, 80vw, 80rem);
    font-size: clamp(1.6rem, 2.5vw, 3rem);
    margin-left: auto;
    margin-right: auto;*/
    background: transparent;
    display: flex;
    margin-top: 1px; ;
    justify-content: space-between;
    align-items: center;
    padding: 5px;
}

.header img {
    width: clamp(4rem, 8vw, 6rem);
    height: auto;
    border-radius: 50%;
}
.title {margin:0; font-size:clamp(2rem, 5vw, 3rem); color: black; font-weight: bold;}



.title{ 
    width: clamp(20rem, 70vw, 60rem);
    font-size: clamp(1.3rem, 2.5vw, 3rem);
    margin: auto;
    padding: 1rem;
    font-weight: bold;
    /*width: clamp(21rem, 50vw, 60rem);*/
    text-align: center;
    margin-left: auto;
    margin-right: auto;
    margin-bottom: 5px; 
    color: black;
}

.lesson{ 
    font-size: clamp(1.2rem, 4vw, 2rem);
    width: clamp(21rem, 80vw, 60rem);
    margin-left: auto;
    margin-right: auto;
    margin-bottom: 15px; 
    color: black;
    line-height: 1.3;
    border-color: blue;
}

/*---------------------------------------------------*/
.topic {
    width: clamp(20rem, 80vw, 60rem);
    display: flex;
    align-items: center;
    font-size: clamp(1rem, 1.5vw, 2.2rem);
    padding: 5px;
    line-height: 1.2;
    box-sizing: border-box;
    /*border: 1px solid red;  /*for visual testing */
}
/*managing the image clock */
.button {
    flex-shrink: 0;
    width: 30px;
    height: 30px;
    margin-right: 5px;
}

.button img {
    width: clamp(1.8rem, 3vw, 2rem);
    height: auto;
    display: block;
}

.toggle-box {
    flex: 1 1 0;
    min-width: 0;
    width: clamp(20rem, 80vw, 60rem);
    font-size: clamp(1.2rem, 1.8vw, 1.7rem);
    padding: 0.3rem;
    word-break: break-word;
    line-height: 1.2;
    cursor: pointer;
    border: 1px;
    /*border: 1px solid green; /* for visual testing */
}
/*
.topic { border: 1px dashed red; }
.button { border: 1px solid blue; }
.toggle-box { border: 1px solid green; }
*/



@media screen and (max-width: 400px) {
    .topic {
        flex-wrap: wrap;
        align-items: flex-start;
    }

    .concept {
        padding-left: 0;
        margin-top: 0.5rem;
    }
}