body {
    /* لتجنب الانزلاق لأعلى عند جعل الهيدر ثابتًا */
    margin: 0;
    padding: 0;
}

header {
    background-color: #1A106A; /* لون خلفية الهيدر */
    color: #fff; /* لون النص في الهيدر */
    padding: 10px; /* هامش داخلي للهيدر لجعله أكثر جمالًا */
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000; /* لضمان أن الهيدر يظهر فوق أي محتوى آخر */
}


/* spilt the page */

 .split {
    height: 100%;
    width: 50%;
    position: fixed;
    z-index: 1;
    top: 18%;
    overflow-x: hidden;
    padding-top: 20px;

} 

.left {
    left: 0;
    background-color: #ffffff;
}

.right {
    right: 0;
    background-color: #ffffff;
}

.center {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
}

.title {
    text-align: center;
}

/* left section */

#cipher {
    width: 100%;
    font-size: 1.5em;
}

#cipher .top,
#cipher #bottom {
    clear: both;
    float: left;
    width: 26em;
    /* same alphabet length */
    padding: 0;
    height: 1.1em;
}

#cipher #bottom {
    overflow: hidden;
    position: relative;
    background: #eee;
}

#cipher #shift {
    float: left;
}

/*#letters {}*/

#cover {
    position: absolute;
    width: 100%;
    height: 100%;
}

#cipher .letter {
    float: left;
    width: 1em;
}

#plaintext,
#ciphertext {
    width: 50%;
    float: left;
}

textarea {
    width: 100%;
    font-size: 1em;
    font-family: serif;
    height: 3em;
    border-color: black;
    border-width: 0.5mm;
}

#cryptographer {
    clear: both;
    font-size: 1.5em;
}

/* right section */

/* Base styles for this example */

.wrapper {
    width: 50vw;
    /* unfortunately width has to be set to some hard value */
    display: flex;
}

.slide {
    width: 0;
}

.content {
    width: 50vw;
    height: 100%;
    /* this is optional if you want every slide to have same height as the highest one */
}

/* Additional styling */

/* html,
body {
    background-color: #BDBDBD;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    font-family: Lato;
} */

.wrapper {
    margin: 0 auto;
    background-color: white;
    /*box-shadow: 3px 3px 20px #9E9E9E; هي اللي تعطيني شكل السلايد*/ 
}

.span-ceaser {
    background-color: rgb(113, 239, 235);
    text-align: center;
    line-height: 4rem;
    width: 4rem;
    border-radius: 8rem;
    color: #4d4747;
    font-size: 2rem;
}

.content {
    padding: 30px;
    opacity: 0;
    pointer-events: none;
    transition: opacity .6s;
    max-height: 90vh;
    overflow-y: auto;
}

/* .content3,
.content5,
.content6 {
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #E0E0E0;
}*/

.content2 {
    background-image: url(img.gif);
    background-size: contain;
    background-position: center;
    background-repeat: no-repeat; 
}

#i_1:checked~.wrapper .content1,
#i_2:checked~.wrapper .content2,
#i_3:checked~.wrapper .content3,
#i_4:checked~.wrapper .content4 {
    opacity: 1;
    pointer-events: auto;
}

label {
    color: #000000;
    transition-duration: .6s;
    cursor: pointer;
}

#i_1:checked~.controls label[for="i_1"],
#i_2:checked~.controls label[for="i_2"],
#i_3:checked~.controls label[for="i_3"],
#i_4:checked~.controls label[for="i_4"] {
    color: rgb(113, 239, 235);
}