refactor: Modularize CSS and fix theme-aware text colors

CSS Restructuring:
- Reorganize monolithic main.css into modular architecture
- Create foundation/ (reset, variables, typography, themes)
- Create layout/ (container, page, grid, paper)
- Create components/ (8 component files)
- Create interactive/ (toggles, remaining for future split)
- Create effects/ (skeleton loading)
- Create contexts/ (print styles)

Theme Support Fixes:
- Replace all hardcoded text colors with CSS variables
- Fix .section-title: rgb(51,51,51) → var(--text-primary)
- Fix .cv-name, .intro-text: hardcoded → theme-aware
- Fix .experience-period, .duration-text: #555/#aaa → variables
- Fix course/project/experience text colors
- Support proper light/dark theme text contrast

Icon & Layout Fixes:
- Standardize all icon sizes to 80×80px
- Change all icon backgrounds to transparent
- Fix award section layout (missing flexbox)
- Update HTML templates (experience.html, awards.html) to width='80'
- Fix default icon sizing conflicts

View Switcher Fix:
- Fix toggleTheme() to target .cv-container instead of body
- Ensures clean/default theme toggle works correctly

Files: 40+ CSS files modularized, 3 templates updated, 7 tests added

static/css/01-foundation/_typography.css

@@ -0,0 +1,28 @@
+/* ============================================================================
+   TYPOGRAPHY - Fonts & Text Styles
+   ============================================================================ */
+
+/* Font Imports */
+@import url('https://fonts.googleapis.com/css2?family=Quicksand:wght@400;500;600;700&family=Source+Sans+Pro:wght@400;600&family=Inter:wght@400;500;600;700&display=swap');
+
+/* Base Typography */
+body {
+  font-family: 'Quicksand', 'Source Sans Pro', -apple-system, system-ui, sans-serif;
+  color: var(--text-secondary);
+  line-height: 1.5;
+  font-size: 16px;
+  font-weight: 400;
+  font-smoothing: antialiased;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+}
+
+/* Links */
+a {
+  color: var(--accent-blue);
+  text-decoration: none;
+
+  &:hover {
+    text-decoration: underline;
+  }
+}