Each widget has a wrap that adds the padding. The gray sections are located on line 1403 –
.home-feature-bg .wrap {
margin: 0 auto;
overflow: hidden;
padding: 120px 0 80px;
width: 1140px;
}
The white sections are located on line 1464 –
.home-feature-bg-alt .wrap {
margin: 0 auto;
overflow: hidden;
padding: 120px 0 80px;
width: 1140px;
}
The code above handles all of those widget areas.