* {
    box-sizing: border-box;
}
body {
    min-width: 100%;
    overflow-x: hidden;
    margin: 0;
    padding: 0;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background-image: url('background.jpeg');
    background-attachment: fixed;
    background-position: center center;
    background-repeat: no-repeat;
}
@keyframes gradient {
    0% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
    100% {
        background-position: 0% 50%;
    }
}

::-webkit-scrollbar {
  width: 10px;
}
::-webkit-scrollbar-track {
  box-shadow: inset 0 0 8px grey;
  border-radius: 2px;
}
::-webkit-scrollbar-thumb {
  background-image: linear-gradient(
    to bottom,
    rgba(255, 0, 0, 0.55),
    rgba(0, 128, 0, 0.55),
    rgba(0, 0, 255, 0.55)
  );
  border-radius: 2px;
}
::-webkit-scrollbar-thumb:hover {
  background-image: linear-gradient(to bottom, red, green, blue);
}

#page {
    margin: 0;
    padding: 0;
    flex: 1;
    min-width: 100%;
}

#logo-section {
    margin: 20px auto;
    text-align: center;
}
#logo {
    width: 200px;
    height: 200px;
}

#intro-section {
    margin: 0 auto;
    text-align: center;
}

.heading{
    font-size: 25px;
    font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
    color: #fff;
    text-shadow: 0 0 5px #ff005e, 0 0 10px #ff005e, 0 0 20px #ff005e, 0 0 40px #ff005e, 0 0 80px #ff005e;
    animation: glow 1.5s infinite alternate;
}

@keyframes glow {
    0% {
        text-shadow: 0 0 5px #ff005e, 0 0 10px #ff005e, 0 0 20px #ff005e, 0 0 40px #ff005e, 0 0 80px #ff005e;
    }
    100% {
        text-shadow: 0 0 10px #00d4ff, 0 0 20px #00d4ff, 0 0 40px #00d4ff, 0 0 80px #00d4ff, 0 0 160px #00d4ff;
    }
}

.chapter {
    margin: 20px auto;
    text-align: center;
}

.chapter:last-child {
    margin-bottom: 0;
}

.textbox {
    margin: 0 auto;
    max-width: 1000px;
    height: auto;
    padding: 20px;
    border: 2px ridge crimson;
    border-radius: 5px;
    font-size: 15px;
    font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
    background-color: #424244;
    color: white;
    text-align: center;
}

@media screen and (max-width: 768px) {
    iframe, video {
        width: 100%;
        height: auto;
        display: block;
        max-width: 100%;
    }
    #intro-section {
        max-width: 650px;
        height: auto;
    }
    .chapter {
        max-width: 650px;
        height: auto;
    }
}

@media screen and (max-width: 480px) {
    #logo {
        width: 100px;
        height: 100px;
    }
    iframe, video {
        width: 100%;
        height: auto;
        display: block;
        max-width: 100%;
    }
    #intro-section {
        max-width: 350px;
        height: auto;
    }
    .chapter {
        max-width: 350px;
        height: auto;
    }
    #footer {
        min-width: 100%;
        border-radius: 25px;
    }
}

#footer {
    color: #424244;
    position: relative;
    left: 0;
    right: 0;
    margin-left: 0;
    margin-right: 0;
    flex-shrink: 0;
    align-self: stretch;
    width: 100%;
    max-width: none;
    font-size: 15px;
    font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
    background-color: #feeb1c;
    margin: 0;
    padding: 15px 0;
    text-align: center;
}

.buttons {
    display: inline-block;
    margin-right: 5px;
    padding: 8px;
    font-family: Tahoma;
    border: none;
    outline: none;
    cursor: pointer;
    background-color: #3932f3;
    color: white;
    font-size: 15px;
    border-radius: 5px;
    text-decoration: none;
}

.buttons:hover {
    background-color: crimson;
}

.buttons:last-child {
    margin-right: 0;
}