:root {
   --primary-color: #425b84;
   --secondary-color: #5b7bb4;
   --max-width: 1100px; 
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font: normal 1rem/1.5 'Arial', sans-serif;
    background: var(--primary-color);
    color: #fff;
    overflow-x: hidden;
    padding-bottom: 50px;
}

#main-header {
    background: var(--secondary-color);
    padding: 4rem 0;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    text-align: center;
}

h1 {
    font-size: 2.3rem;
}

#timeline ul {
    background: var(--primary-color);
    padding: 50px 0;
}
/* Create line */
#timeline ul li {
    list-style: none;
    position: relative;
    width: 7px;
    margin: 0 auto;
    padding-top: 50px;
    background: #fff;
}
/* Boxes */
#timeline ul li div {
    position: relative;
    bottom: 0;
    width: 400px;
    padding: 1rem;
    background: var(--secondary-color);
    transition: all 0.5s ease-in-out;
    visibility: hidden;
    opacity: 0;
}

.pic {
    text-align: center;
    padding-top: 10px;
}

.pic img {
    width: 100%;
}

/* Right Side */
#timeline ul li:nth-child(odd) div {
    left: 40px;
    transform: translate(200px, 0);
}

/* Left Side */
#timeline ul li:nth-child(even) div {
    left: -438px;
    transform: translate(-200px, 0);
}

/* Dots */
#timeline ul li:after {
    content: '';
    position: absolute;
    left: 50%;
    bottom: 0;
    width: 25px;
    height: 25px;
    background: inherit;
    transform: translateX(-50%);
    border-radius: 50%;
    transition: background 0.5s ease-in-out;
}

/* Arrows Base Style*/
#timeline div:before {
    content: '';
    position: absolute;
    bottom: 5px;
    width: 0;
    height: 0;
    border-style: solid;
}

/* Right Side Arrows */
#timeline ul li:nth-child(odd) div:before {
    left: -15px;
    border-width: 8px 16px 8px 0;
    border-color: transparent var(--secondary-color) transparent transparent;
}
/* Left Side Arrows */
#timeline ul li:nth-child(even) div:before {
    right: -15px;
    border-width: 8px 0px 8px 16px;
    border-color: transparent transparent transparent var(--secondary-color);
}

/* Show Boxes */
#timeline ul li.show div {
    transform: none;
    visibility: visible;
    opacity: 1;
}

#timeline ul li.show:after {
    background: var(--secondary-color)
}
/* Media Query  */ 
@media(max-width: 900px) {
    #timeline ul li div {
        width: 250px;
    }

    #timeline ul li:nth-child(even) div {
       left: -300px;
    }
}
@media(max-width: 600px) {
    #timeline ul li {
        margin-left: 20px;
    }
    
    #timeline ul li div {
        width: calc(100vw - 90px);
    }

    #timeline ul li:nth-child(even) div {
        left: 40px;
    }

    #timeline ul li:nth-child(even) div:before {
       left: -15px;
       border-width: 8px 16px 8px 0;
       border-color: transparent var(--secondary-color) transparent transparent
    }
    h3 {
        text-align: center;
    }
  
}
@media(max-width: 280px) { 
.pic img {
    width: 150px;
} 
}