问题
I want to have a basic HSL color value which I want to implement as a gradient as follows:
:root {
--hue: 201;
--saturation: 31;
--lightness: 40;
--mainColor: hsl(var(--hue),var(--saturation),var(--lightness));
--difference: 20; /* 0 + --difference < --lightness < 100 - --difference */
--lightnessPlus: calc(var(--lightness) + var(--difference));
--colorFrom: hsl(var(--hue),var(--saturation),var(--lightnessPlus));
--lightnessMinus: calc(var(--lightness) - var(--difference));
--colorTo: hsl(var(--hue),var(--saturation),var(--lightnessMinus));
}
[...]
.class {
background-image: linear-gradient(to right, var(--colorFrom), var(--colorTo));
}
The above code produces a transparent object and I fail to comprehend why, please help!
回答1:
You are missing percentages. the syntax should be hsl(h, s%, l%)
(https://drafts.csswg.org/css-color-3/#hsl-color)
:root {
--hue: 201;
--saturation: 31%; /* here */
--lightness: 40;
--mainColor: hsl(var(--hue),var(--saturation),var(--lightness));
--difference: 20;
--lightnessPlus: calc((var(--lightness) + var(--difference))*1%); /* here */
--colorFrom: hsl(var(--hue),var(--saturation),var(--lightnessPlus));
--lightnessMinus: calc((var(--lightness) - var(--difference))*1%); /* here */
--colorTo: hsl(var(--hue),var(--saturation),var(--lightnessMinus));
}
body {
background-image: linear-gradient(to right, var(--colorFrom), var(--colorTo));
}
Or
:root {
--hue: 201;
--saturation: 31%; /* here */
--lightness: 40%; /* here */
--mainColor: hsl(var(--hue),var(--saturation),var(--lightness));
--difference: 20%; /* here */
--lightnessPlus: calc(var(--lightness) + var(--difference));
--colorFrom: hsl(var(--hue),var(--saturation),var(--lightnessPlus));
--lightnessMinus: calc(var(--lightness) - var(--difference));
--colorTo: hsl(var(--hue),var(--saturation),var(--lightnessMinus));
}
body {
background-image: linear-gradient(to right, var(--colorFrom), var(--colorTo));
}
来源:https://stackoverflow.com/questions/65478345/css-variable-calculation-of-hsl-values