Techniques
Diff-line color coding
GitHub's iconic code review coloring — addition lines get a green-tinted background, deletions get red-tinted, with the specific changed characters highlighted more intensely.
.diff-line-add {
background-color: rgba(63, 185, 80, 0.15);
border-left: 3px solid #3fb950;
}
.diff-line-add .highlight {
background-color: rgba(63, 185, 80, 0.4);
}
.diff-line-remove {
background-color: rgba(248, 81, 73, 0.15);
border-left: 3px solid #f85149;
}
.diff-line-remove .highlight {
background-color: rgba(248, 81, 73, 0.4);
}
One-pixel border card
GitHub's universal container pattern — no shadow, just a crisp 1px border on the cool-blue-grey #30363d, with a slightly elevated surface fill.
.gh-card {
background: #0d1117;
border: 1px solid #30363d;
border-radius: 6px;
padding: 16px;
transition: border-color 200ms cubic-bezier(0.4, 0, 0.2, 1);
}
.gh-card:hover {
border-color: #484f58;
}
Merge button gradient
GitHub's primary action button for merging pull requests — a solid green that lightens on hover, with a subtle inner border for dimension against the dark canvas.
.merge-button {
background-color: #238636;
color: #ffffff;
border: 1px solid rgba(240, 246, 252, 0.1);
border-radius: 6px;
padding: 5px 16px;
font-weight: 600;
font-size: 14px;
line-height: 20px;
transition: background-color 200ms cubic-bezier(0.4, 0, 0.2, 1);
}
.merge-button:hover {
background-color: #2ea043;
}
.merge-button:focus {
box-shadow: 0 0 0 3px rgba(46, 160, 67, 0.4);
outline: none;
}