* {
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Open Sans', sans-serif;
  color: #111;
  background-color: #eee;
}

h1 {
  margin: 1em 0;
  font-size: 200%;
}

p {
  text-align: center;
}

a {
  color: #777;
  text-decoration: none;
}

a:hover {
  color: #aaa;
}

.talk {
  width: 700px;
  margin: 0 auto;
  padding-bottom: 20px;
  text-align: center;
}

.slides {
  padding-top: 20px;
  margin: auto;
}

#avatar img{
  width: 60px;
  border-radius: 100px;
}

#social {
  margin: 60px 0 0 0;
  font-size: 60px;
}

#bio {
  font-size: 16px;
  line-height: 160%;
}

* {
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Open Sans', sans-serif;
  color: #111;
  background-color: #eee;
}

h1 {
  margin: 1em 0;
  font-size: 2em;
}

p {
  text-align: center;
}

a {
  color: #777;
  text-decoration: none;
}

a:hover {
  color: #aaa;
}

.talk {
  width: 700px;
  margin: 0 auto;
  padding-bottom: 20px;
  text-align: center;
}

.slides {
  padding-top: 20px;
  margin: auto;
}

#avatar img{
  width: 60px;
  border-radius: 100px;
}

#social {
  margin: 60px 0 0 0;
  font-size: 60px;
}

#bio {
  font-size: 16px;
  line-height: 160%;
}

Use em instead of percentage
Use em instead of percentage
