HTMLify

@import url(https://fonts.googleapis.com/css?family=Roboto);

html {
  font-family: 'Roboto', sans-serif;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #007FFF;
    --secondary: #6F7E8C;
    --box: #F5F5F5;
    --text: #212121;
}

.centering {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    width: 100vw;
    background: var(--primary);
}

.box {
    background-color: var(--box);
    max-width: 400px;
    width: 100%;
    min-height: 200px;
    display: grid;
    place-items: center;
    border-radius: 24px;
}

.search {
    position: relative;
    width: 64px;
    height: 64px;
    border-radius: 40px;
    padding: 10px;
    cursor: pointer;
    background-repeat: no-repeat;
    font-size: 24px;
    color: transparent;
    border: 3px solid var(--primary);
    transition: width 300ms, background-position 300ms;
    overflow: hidden;
    background: url(search-bold.svg) no-repeat transparent;
    background-size: 40px;
    background-position: 45% 50%;
} 

.search:hover {
    cursor: pointer;
    border: 3px solid var(--primary);
    background: url(search-bold.svg) no-repeat transparent;
    background-size: 40px;
    background-position: 45% 50%;
}

.search:focus, .search:not(:placeholder-shown) {
    max-width: 300px;
    width: 100%;
    cursor: text;
    color: var(--primary);
    padding-left: 60px;
    outline: none;
    transition: width 500ms, background-position 300ms;
    border: 3px solid var(--primary);
    background-color: transparent;
    background: url(search-bold.svg) no-repeat;
    background-size: 40px;
    background-position: 10px 50%;
}