misuzu/assets/less/input/upload.less

.input__upload {
    display: inline-block;
    cursor: pointer;
    margin: 1px 0;

    &__input {
        display: inline-block;
        position: absolute;
        z-index: -1000;
    }

    &__selection {
        text-align: center;
        font-size: 1.2em;
        border: 1px solid #222;
        padding: 5px 10px;
        background: #222;
        color: #fff;
        border-radius: 2px;
        box-shadow: inset 0 0 4px #111;
        transition: border-color .2s;
        overflow: hidden;
        word-wrap: break-word;
    }

    &:focus-within &__selection,
    &__input:focus ~ &__selection,
    &__input:active ~ &__selection {
        border-color: @accent-colour;
        border-color: var(--accent-colour);
    }
}