Massive Buttons skin by AO3 

These are really big and bold. You might want to take off the box shadow
Role:
user
Media:
screen
Condition:
Normal

CSS

.actions a,
.actions a:visited,
.action,
.actions input,
input[type="submit"],
button,
.current,
.actions label,
.actions a:hover {
  color: #2a2a2a;
  font-size: 130%;
  margin: 0.15em;
  border: 2px solid #777;
  box-shadow: 2px 2px 2px;
}

.actions a:hover,
.actions input[type="submit"]:hover,
.current {
  background: #000;
  border-color: #fff;
  color: #fff;
  box-shadow: none;
}