body {
    width: 100vw;
    height: 100vh;
    margin: 0;
    padding: 0;
    background: linear-gradient(
            135deg,
            hsl(170, 80%, 70%),
            hsl(190, 80%, 70%),
            hsl(250, 80%, 70%),
            hsl(320, 80%, 70%)
    );
    background-size: 200% 200%;
    animation: gradient-move 15s ease alternate infinite;
    font-family: Roboto;
    -webkit-text-size-adjust: 100%;
    -webkit-font-smoothing: antialiased;
}

@keyframes gradient-move {
    0% {
        background-position: 0% 0%;
    }
    100% {
        background-position: 100% 100%;
    }
}

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

button {
    width: 100%;
    background-color: #3498db;
    border: 0;
    padding: 10px 0;
    margin: 10px 0;
    color: #fff;
    text-align: center;
    font-weight: bold;
}

.inp * {
    box-sizing: border-box;
}

.inp {
    display: grid;
    position: relative;
    margin: auto;
    width: 800px;
    border-radius: 3px;
    overflow: hidden;
}

.inp.short {
    display: block;
    width: 300px;
}

.inp .label {
    position: absolute;
    top: 20px;
    left: 12px;
    font-size: 16px;
    color: rgba(0, 0, 0, 0.5);
    font-weight: 500;
    transform-origin: 0 0;
    transform: translate3d(0, 0, 0);
    transition: all 0.2s ease;
    pointer-events: none;
}

.inp .focus-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.05);
    z-index: -1;
    transform: scaleX(0);
    transform-origin: left;
}

.inp input {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    width: 100%;
    border: 0;
    font-family: inherit;
    padding: 16px 12px 0 12px;
    height: 56px;
    font-size: 16px;
    font-weight: 400;
    background: rgba(0, 0, 0, 0.02);
    box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.3);
    color: #000;
    transition: all 0.15s ease;
}

.inp input:hover {
    background: rgba(0, 0, 0, 0.04);
    box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.5);
}

.inp input:not(:-moz-placeholder-shown) + .label {
    color: rgba(0, 0, 0, 0.5);
    transform: translate3d(0, -12px, 0) scale(0.75);
}

.inp input:not(:-ms-input-placeholder) + .label {
    color: rgba(0, 0, 0, 0.5);
    transform: translate3d(0, -12px, 0) scale(0.75);
}

.inp input:not(:placeholder-shown) + .label {
    color: rgba(0, 0, 0, 0.5);
    transform: translate3d(0, -12px, 0) scale(0.75);
}

.inp input:focus {
    background: rgba(0, 0, 0, 0.05);
    outline: none;
    box-shadow: inset 0 -2px 0 #0077FF;
}

.inp input:focus + .label {
    color: #0077FF;
    transform: translate3d(0, -12px, 0) scale(0.75);
}

.inp input:focus + .label + .focus-bg {
    transform: scaleX(1);
    transition: all 0.1s ease;
}