.triangle-buttons__triangle {
    border-style: solid;

    /* Size */
    height: 0;
    width: 0;
}

.triangle-buttons__triangle--t {
    border-color: transparent transparent #d1d5db;
    border-width: 0 0.5rem 0.5rem;
}

.triangle-buttons__triangle--r {
    border-color: transparent transparent transparent #d1d5db;
    border-width: 0.5rem 0 0.5rem 0.5rem;
}

.triangle-buttons__triangle--b {
    border-color: #d1d5db transparent transparent;
    border-width: 0.5rem 0.5rem 0;
}

.triangle-buttons__triangle--l {
    border-color: transparent #d1d5db transparent transparent;
    border-width: 0.5rem 0.5rem 0.5rem 0;
}

/* Demo */
.triangle-buttons {
    position: relative;
    height: 100%;
    width: 100%;
}
.triangle-buttons__corner {
    position: absolute;
}
.triangle-buttons__corner--t {
    left: 50%;
    top: 0;
    transform: translate(-50%, 0%);
}
.triangle-buttons__corner--r {
    right: 0;
    top: 50%;
    transform: translate(0%, -50%);
}
.triangle-buttons__corner--b {
    bottom: 0;
    left: 50%;
    transform: translate(-50%, 0%);
}
.triangle-buttons__corner--l {
    left: 0;
    top: 50%;
    transform: translate(0%, -50%);
}