@keyframes slide {
  0% {
    top: 0;
    color: black;
  }
  50% {
    color: grey;
  }
  100% {
    top: 25%;
    color: white;
  }
}
html {
  scroll-behavior: smooth;
}
body {
  background: #353434;
  color: white;
  margin: 0;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}
header {
  text-align: center;
}
main a {
  font-weight: bold;
  color: white;
  text-decoration: none;
  border-radius: 5px;
  border: 1px transparent solid;
  transition: 1s;
}
main a:hover {
  border: 1px rgb(170, 40, 40) solid;
  background-color: #646464;
}
.container {
  display: grid;
  /* grid-template-columns: 50% auto; */
  padding: 10px;
}
.background {
  background-image: linear-gradient(rgba(0, 0, 0, 0.65), rgba(0, 0, 0, 0.7)),
    url(/img/background.webp);
  background-size: cover;
  height: 100vh;
}

.source {
  position: absolute;
  bottom: 0;
  right: 0;
  margin: 10px;
  color: gray;
}
.center {
  text-align: center;
}
.bold {
  font-weight: bold;
}
.exercises {
  margin: 100px 0;
}
.exercise {
  background-color: rgba(85, 85, 85, 0.35);
  margin: 5px;
  border-radius: 10px;
}
.exercise ul {
  display: grid;
  /* grid-template-columns: 50% auto; */
  list-style: none;
  padding: 0;
  align-self: center;
}
.exercise ul li {
  margin: 5px;
  background-color: rgba(94, 94, 94, 0.4);
  border-radius: 5px;
  height: 50px;
  border: 0;
}
.exercise ul li a {
  display: block;
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}
.name {
  font-size: 40px;
  max-width: 320px;
  margin: auto;
  position: relative;
  top: 25%;
  animation-name: slide;
  animation-duration: 2.5s;
}
header {
  position: fixed;
  width: 100%;
  background-color: rgba(85, 85, 85, 0.4);
}
#menu {
  list-style: none;
  display: flex;
  width: 100%;
  gap: 15%;
  margin-left: 10%;
}
.menu-item {
  text-decoration: none;
}
.menu-item a {
  text-decoration: none;
  color: white;
  transition: 1s;
}
.menu-item a:hover {
  color: red;
}
.container {
  max-width: 1300px;
  margin: auto;
}

@media only screen and (min-width: 800px) {
  .container {
    grid-template-columns: 50% auto;
  }
  .exercise ul {
    grid-template-columns: 50% auto;
  }
}
@media only screen and (max-width: 800px) {
  .container {
    grid-template-columns: auto;
  }
  .exercise ul {
    grid-template-columns: 50% auto;
  }
}
@media only screen and (max-width: 600px) {
  .container {
    grid-template-columns: auto;
  }
  .exercise ul {
    grid-template-columns: auto;
  }
}