What's the difference between `.class1.class2` and `.class1 .class2` CSS rule?
Spacing in between class specifiers means a ascendant -> descendant relationship.
The rule:
.test .heading { font-weight: bold; }
Would apply to the <p> element here:
<span class="test"><p class="heading">Something</p></span>
The lack of space means that the element must have both classes for the rule to apply.
The rule:
.heading.major { color: blue; }
Would apply to the <p> element here:
<p class="heading major">Major heading</p>
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.class1.class2
= matches element that has both classes.
.class1 .class2
= matches element with class2 inside element with class1.