@import url("https://fonts.googleapis.com/css2?family=Poppins:wght@300;500;700&display=swap");

.timeline-container *,
.timeline-container *::before,
.timeline-container *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.timeline-container {
    display: grid;
    align-content: center;
    gap: 2rem;
    padding: 2rem;
    font-family: "Poppins", sans-serif;
}

h1 {
    text-align: center;
}

.timeline-container ul {
    --col-gap: 2rem;
    --row-gap: 2rem;
    --line-w: 0.25rem;
    display: grid;
    grid-template-columns: var(--line-w) 1fr;
    grid-auto-columns: max-content;
    column-gap: var(--col-gap);
    list-style: none;
    width: min(60rem, 90%);
    margin-inline: auto;
}

/* line */
.timeline-container ul::before {
    content: "";
    grid-column: 1;
    grid-row: 1 / span 20;
    background: rgb(225, 225, 225);
    border-radius: calc(var(--line-w) / 2);
}

/* columns*/

/* row gaps */
.timeline-container ul li:not(:last-child) {
    margin-bottom: var(--row-gap);
}

/* card */
.timeline-container ul li {
    grid-column: 2;
    --inlineP: 1.5rem;
    margin-inline: var(--inlineP);
    grid-row: span 2;
    display: grid;
    grid-template-rows: min-content min-content min-content;
}

/* title */
.timeline-container ul li .title {
    --titleH: 3rem;
    height: var(--titleH);
    margin-inline: calc(var(--inlineP) * -1);

    text-align: center;
    background-color: var(--primary-color);

    color: var(--text-primary);
    font-size: 1.25rem;
    font-weight: 700;

    display: grid;
    place-content: center;
    position: relative;

    border-radius: calc(var(--titleH) / 2) 0 0 calc(var(--titleH) / 2);
}

/* title flap */
.timeline-container ul li .title::before {
    content: "";
    width: var(--inlineP);
    aspect-ratio: 1;
    background: var(--primary-color);
    background-image: linear-gradient(rgba(0, 0, 0, 0.2) 100%, transparent);
    position: absolute;
    top: 100%;

    clip-path: polygon(0 0, 100% 0, 0 100%);
    right: 0;
}

/* circle */
.timeline-container ul li .title::after {
    content: "";
    position: absolute;
    width: 2rem;
    aspect-ratio: 1;
    border: 0.3rem solid var(--primary-color);
    border-radius: 50%;
    top: 50%;

    transform: translate(50%, -50%);
    right: calc(100% + var(--col-gap) + var(--line-w) / 2);
}

/* descr */
.timeline-container ul li .description {
    position: relative;
    padding-inline: 1.5rem;
    margin-top: 1rem;
}
.timeline-container ul li .description {
    padding-block-end: 1.5rem;
    font-weight: 300;
}

@media (min-width: 991px) {
    .timeline-container ul {
        grid-template-columns: 1fr var(--line-w) 1fr;
    }
    .timeline-container ul::before {
        grid-column: 2;
    }
    .timeline-container ul li:nth-child(odd) {
        grid-column: 1;
    }
    .timeline-container ul li:nth-child(even) {
        grid-column: 3;
    }

    /* start second card */
    .timeline-container ul li:nth-child(2) {
        grid-row: 2/4;
    }

    .timeline-container ul li:nth-child(odd) .title::before {
        clip-path: polygon(0 0, 100% 0, 100% 100%);
        left: 0;
    }

    .timeline-container ul li:nth-child(odd) .title::after {
        transform: translate(-50%, -50%);
        left: calc(100% + var(--col-gap) + var(--line-w) / 2);
    }
    .timeline-container ul li:nth-child(odd) .title {
        border-radius: 0 calc(var(--titleH) / 2) calc(var(--titleH) / 2) 0;
    }

    .timeline-container ul .description {
        margin-bottom: 2rem;
    }
}