collage-maker/web/index.css

.container {
    display: flex;
    background-color: lightyellow;
    height: calc(100vh - 20px);
}
.controls {
    background-color: lightgrey;
    display: flex;
    align-items: center;
    justify-content: space-around;
    flex-direction: column;
    flex: 25%;
}
.imagebox {
    padding: 2rem;
    flex: 75%;
}

.image-surface {
    overflow: hidden;
    margin: auto;
    border: 1px solid;
    height: 100%;
    width: auto;
    --collage-ap: 110 / 85;
    aspect-ratio: var(--collage-ap);
}
.showbuton {
    font-size: 2rem;
}

.templates {
    display: flex;
    flex-wrap: wrap;
     gap: 1rem;
}

.templates li {
    list-style-type: none;
}

#page_size_selector {
    width: 100%;
}

.template {
    width: 100px;
    height: 100px;
}

.template div {
    border: 1px solid;
}

.single div {
    width: 100%;
    height: 100%;
}

.one-two {
    display: grid;
    grid-template-areas: 
    "one two"
    "one three";
}
.one-two .img1{
    grid-area: one;
}

.half-leftright {
    display:flex;
}

.half-leftright .img {
    flex: 50%;
}

.half-topbottom .img {
    width: 100%;
    height: 50%;
}

.two-one-two-leftright {
    display: grid;
    grid-template-areas: 
    "one two two three"
    "four two two five";
}
.two-one-two-leftright .img2 {
    grid-area: two;
}

.two-one-two-topbottom {
    display: grid;
    grid-template-areas: 
    "one two"
    "three three"
    "three three"
    "four five"
}

.two-one-two-topbottom .img3 {
    grid-area: three;
}