style.css

* {
    margin: 0;
    padding: 0;
    font-family: Sans-Serif;
    box-sizing: border-box;
}
html, body {
    height: 100%;
    width: 100%;
}
body {
    justify-content: center;
    align-items: center;
    display: flex;
    background-color: grey;
}
.window1 {
    background: #fff;
    width: 60%;
    height: auto;
    resize: both;
    overflow: auto;
    /*display: none; */
}
.window1 .header-w1 {
    background: #000;
    justify-content: space-between;
    align-items: center;
    display: flex;
    padding: 5px;
    width: 100%;
}
.header-w1 span {
    color: #fff;
}
.header-w1 button {
    background: red;
    color: #000;
}
.window1 .content-w1 {
    padding: 10px;
}
.content-w1 p {
    color: #444;
}
.content-w1 button {
    padding: 2px 5px;
    background: #00FF5B;
    color: #000;
    border-radius: 1.5px;
    margin-top: 5px;
}

/* WINDOW 2 */

.window2 {
    background: #fff;
    width: 100%;
    height: 100%;
    overflow: auto;
    display: none;
}
.window2 .header-w2 {
    background: #000;
    justify-content: space-between;
    align-items: center;
    display: flex;
    padding: 5px;
    width: 100%;
}
.header-w2 span {
    color: #fff;
}
.header-w2 .actions {
    justify-content: space-between;
    align-items: center;
    display: flex;
    gap: 5px;
}
.actions button {
    padding: 2px;
    width: 30px;
}
.actions .minimize {
    background: #00FF1C;
}
.actions .close {
    background: red;
}
.window2 .content-w2 {
    margin-top: 5px;
    padding: 10px;
    justify-content: center;
    align-items: center;
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.content-w2 input {
    text-indent: 5px;
    border: 0.5px solid grey;
    box-shadow: 1px 1px 2px grey;
    height: 25px;
    width: 225px;
    border-radius: 2.5px;
}
.content-w2 form {
    justify-content: center;
    align-items: center;
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.content-w2 button {
    background: red;
    color: #fff;
    padding: 2.5px;
    height: 25;
    width: 225px;
    border-radius: 2.5px;
}