Modern CSS Color Declarations
Hexadecimal color notation is universally supported across every web browser since HTML 1.0. Modern CSS expands hex support to include 8-digit alpha transparency and CSS custom property theming.
1. Standard CSS Properties with Hex Codes
.card {
color: #0F172A; /* Text color */
background-color: #FFFFFF; /* Surface */
border: 1px solid #E2E8F0; /* Border */
box-shadow: 0 4px 12px #0F172A1A; /* 10% opacity shadow */
}
2. CSS Custom Properties for Dynamic Theming
:root {
--primary: #3B82F6;
--primary-hover: #2563EB;
--bg: #F8FAFC;
}
[data-theme='dark'] {
--bg: #0F172A;
}