feat: enhance experience section with icons, duration, and improved styling

Experience Section Improvements:
- Increased company logo size from 48px to 64px
- Added default office building icon for companies without logos
- Increased spacing between entries (2.5rem margin, 2rem padding)
- Added visible separator lines (2px solid #ddd)
- Made dates bold (weight: 600) and larger (1.05rem)
- Changed date color to #555 for better contrast

Dynamic Duration Calculation:
- Added automatic years/months calculation for each position
- Format: "(4 years 10 months)", "(2 years)", "(6 months)"
- Smart pluralization in English and Spanish
- Handles current positions (calculates to today)
- Added Duration field to Experience model

Iconify Integration:
- Added Iconify library (v3.1.1) for icon management
- Replaced EN/ES text with round flag icons (circle-flags:us, circle-flags:es)
- Updated CV site icon to mdi:file-account
- Replaced toggle text with intuitive icons:
  * Short/Long: mdi:file-document-outline / mdi:file-document-multiple-outline
  * Logos: mdi:image-off-outline / mdi:image-multiple-outline
- Default company icon: mdi:office-building (64x64px, light gray background)

Logo Display:
- Logos now show by default (toggle checked on page load)
- Toggle controls icon visibility
- Consistent spacing with default icon placeholder

Files modified:
- internal/handlers/cv.go: Added calculateDuration() function
- internal/models/cv.go: Added Duration field to Experience struct
- templates/index.html: Iconify integration, flag icons, toggle icons
- templates/cv-content.html: Duration display, default icon logic
- static/css/main.css: Bold dates, larger font sizes
- static/css/logo-toggle.css: Icon styling, separator lines, spacing

internal/handlers/cv.go

@@ -48,6 +48,16 @@ func (h *CVHandler) Home(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Calculate duration for each experience
+	for i := range cv.Experience {
+		cv.Experience[i].Duration = calculateDuration(
+			cv.Experience[i].StartDate,
+			cv.Experience[i].EndDate,
+			cv.Experience[i].Current,
+			lang,
+		)
+	}
+
 	// Split skills between left and right sidebars
 	skillsLeft, skillsRight := splitSkills(cv.Skills.Technical)
 
@@ -98,6 +108,16 @@ func (h *CVHandler) CVContent(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Calculate duration for each experience
+	for i := range cv.Experience {
+		cv.Experience[i].Duration = calculateDuration(
+			cv.Experience[i].StartDate,
+			cv.Experience[i].EndDate,
+			cv.Experience[i].Current,
+			lang,
+		)
+	}
+
 	// Split skills between left and right sidebars
 	skillsLeft, skillsRight := splitSkills(cv.Skills.Technical)
 
@@ -207,3 +227,90 @@ func calculateYearsOfExperience() int {
 
 	return years
 }
+
+// calculateDuration calculates the duration between two dates in years and months
+// Date format expected: "YYYY-MM" (e.g., "2021-01")
+// Returns a formatted string like "3 years 6 months" or "6 months"
+func calculateDuration(startDate, endDate string, current bool, lang string) string {
+	// Parse start date
+	start, err := time.Parse("2006-01", startDate)
+	if err != nil {
+		return ""
+	}
+
+	// Determine end date
+	var end time.Time
+	if current {
+		end = time.Now()
+	} else {
+		end, err = time.Parse("2006-01", endDate)
+		if err != nil {
+			return ""
+		}
+	}
+
+	// Calculate total months
+	totalMonths := (end.Year()-start.Year())*12 + int(end.Month()-start.Month())
+
+	// If end date is before start date, return empty
+	if totalMonths < 0 {
+		return ""
+	}
+
+	years := totalMonths / 12
+	months := totalMonths % 12
+
+	// Format the duration string based on language
+	var result string
+	if lang == "es" {
+		if years > 0 && months > 0 {
+			yearStr := "años"
+			if years == 1 {
+				yearStr = "año"
+			}
+			monthStr := "meses"
+			if months == 1 {
+				monthStr = "mes"
+			}
+			result = fmt.Sprintf("(%d %s %d %s)", years, yearStr, months, monthStr)
+		} else if years > 0 {
+			yearStr := "años"
+			if years == 1 {
+				yearStr = "año"
+			}
+			result = fmt.Sprintf("(%d %s)", years, yearStr)
+		} else {
+			monthStr := "meses"
+			if months == 1 {
+				monthStr = "mes"
+			}
+			result = fmt.Sprintf("(%d %s)", months, monthStr)
+		}
+	} else {
+		if years > 0 && months > 0 {
+			yearStr := "years"
+			if years == 1 {
+				yearStr = "year"
+			}
+			monthStr := "months"
+			if months == 1 {
+				monthStr = "month"
+			}
+			result = fmt.Sprintf("(%d %s %d %s)", years, yearStr, months, monthStr)
+		} else if years > 0 {
+			yearStr := "years"
+			if years == 1 {
+				yearStr = "year"
+			}
+			result = fmt.Sprintf("(%d %s)", years, yearStr)
+		} else {
+			monthStr := "months"
+			if months == 1 {
+				monthStr = "month"
+			}
+			result = fmt.Sprintf("(%d %s)", months, monthStr)
+		}
+	}
+
+	return result
+}

internal/models/cv.go

@@ -53,6 +53,7 @@ type Experience struct {
 	Responsibilities []string `json:"responsibilities"`
 	Technologies     []string `json:"technologies"`
 	Highlights       []string `json:"highlights"`
+	Duration         string   `json:"-"` // Calculated field, not from JSON
 }
 
 type AIDevelopment struct {