mybuddy/reports/static_src/scss/timeline.scss

// Adapted for Bootstrap 4 from https://www.bootply.com/SzXin8KDZJ.
$card-shadow: rgba(0, 0, 0, .175);

.timeline {
    list-style: none;
    padding: 10px 0;
    position: relative;

    &::before {
        top: 0;
        bottom: 0;
        position: absolute;
        content: ' ';
        width: 3px;
        background-color: theme-color('primary');
        left: 50%;
        margin-left: -1.5px;

    }

    li {
        margin-bottom: 10px;
        position: relative;

        &::before {
            content: ' ';
            display: table;
        }

        &::after {
            content: ' ';
            display: table;
            clear: both;
        }

        .card {
            width: 47%;
            float: left;
            position: relative;
            box-shadow: 0 1px 6px $card-shadow;

            &::before {
                position: absolute;
                top: 26px;
                right: -15px;
                display: inline-block;
                border-top: 15px solid transparent;
                border-left: 15px solid theme-color('dark');
                border-right: 0 solid theme-color('dark');
                border-bottom: 15px solid transparent;
                content: ' ';
            }

            &::after {
                position: absolute;
                top: 27px;
                right: -14px;
                display: inline-block;
                border-top: 14px solid transparent;
                border-left: 14px solid theme-color('dark');
                border-right: 0 solid theme-color('dark');
                border-bottom: 14px solid transparent;
                content: ' ';
            }
        }

        &.timeline-inverted {
            .card {
                float: right;

                &::before {
                    border-left-width: 0;
                    border-right-width: 15px;
                    left: -15px;
                    right: auto;
                }

                &::after {
                    border-left-width: 0;
                    border-right-width: 14px;
                    left: -14px;
                    right: auto;
                }
            }
        }

        .timeline-badge {
            color: $white;
            width: 50px;
            height: 50px;
            line-height: 50px;
            font-size: 1.4em;
            text-align: center;
            position: absolute;
            top: 16px;
            left: 50%;
            margin-left: -25px;
            background-color: theme-color('dark');
            z-index: 100;
            border-radius: 50%;

            .arrow {
                color: $white;
                width: 50px;
                height: 50px;
                line-height: 50px;
                font-size: 1.4em;
                text-align: center;
                position: absolute;
                top: 26px;
                left: 50%;
                margin-left: -25px;
                background-color: theme-color('dark');
                z-index: 100;
                border-radius: 50%;
            }
        }
    }
}

@media (max-width: 767px) {
    .timeline {
        &::before {
            left: 40px;
        }

        li {
            .card {
                float: right;
                width: calc(100% - 90px);

                &::before {
                    border-left-width: 0;
                    border-right-width: 15px;
                    left: -15px;
                    right: auto;
                }

                &::after {
                    border-left-width: 0;
                    border-right-width: 14px;
                    left: -14px;
                    right: auto;
                }
            }

            .timeline-badge {
                left: 15px;
                margin-left: 0;
                top: 16px;
            }
        }
    }
}