diff --git a/include/docpp.hpp b/include/docpp.hpp
index 5b9105a..2772390 100644
--- a/include/docpp.hpp
+++ b/include/docpp.hpp
@@ -496,6 +496,46 @@ namespace docpp {
                  * @param property The property to push
                  */
                 void push_back(const CSSProperty& property);
+                /**
+                 * @brief Insert a property into the element
+                 * @param index The index to insert the property
+                 * @param property The property to insert
+                 */
+                void insert(const int index, const CSSProperty& property);
+                /**
+                 * @brief Erase a property from the element
+                 * @param index The index of the property to erase
+                 */
+                void erase(const int index);
+                /**
+                 * @brief Find a property in the element
+                 * @param property The property to find
+                 * @return int The index of the property
+                 */
+                int find(const CSSProperty& property);
+                /**
+                 * @brief Find a property in the element
+                 * @param str The property to find
+                 * @return int The index of the property
+                 */
+                int find(const std::string& str);
+                /**
+                 * @brief Swap two properties in the element
+                 * @param index1 The index of the first property
+                 * @param index2 The index of the second property
+                 */
+                void swap(const int index1, const int index2);
+                /**
+                 * @brief Swap two properties in the element
+                 * @param property1 The first property
+                 * @param property2 The second property
+                 */
+                void swap(const CSSProperty& property1, const CSSProperty& property2);
+                /**
+                 * @brief Get the size of the element
+                 * @return int The size of the element
+                 */
+                int size() const;
                 /**
                  * @brief Set the properties of the element
                  * @param properties The properties to set
diff --git a/src/docpp.cpp b/src/docpp.cpp
index 054f8c1..ab937a8 100644
--- a/src/docpp.cpp
+++ b/src/docpp.cpp
@@ -189,6 +189,7 @@ void docpp::HTML::HTMLSection::push_back(const HTMLSection& section) {
 
 void docpp::HTML::HTMLSection::erase(const int index) {
     bool erased{false};
+
     if (this->elements.find(index) != this->elements.end()) {
         this->elements.erase(index);
         erased = true;
@@ -450,6 +451,58 @@ void docpp::CSS::CSSElement::push_back(const CSSProperty& property) {
     this->element.second.push_back(property);
 }
 
+void docpp::CSS::CSSElement::insert(const int index, const CSSProperty& property) {
+    if (index < 0 || index >= this->element.second.size()) {
+        throw std::out_of_range("Index out of range");
+    }
+
+    this->element.second.insert(this->element.second.begin() + index, property);
+}
+
+void docpp::CSS::CSSElement::erase(const int index) {
+    if (index < 0 || index >= this->element.second.size()) {
+        throw std::out_of_range("Index out of range");
+    }
+
+    this->element.second.erase(this->element.second.begin() + index);
+}
+
+int docpp::CSS::CSSElement::find(const CSSProperty& property) {
+    for (int i{0}; i < this->element.second.size(); i++) {
+        if (this->element.second.at(i).get() == property.get()) {
+            return i;
+        }
+    }
+
+    return docpp::CSS::CSSElement::npos;
+}
+
+int docpp::CSS::CSSElement::find(const std::string& str) {
+    for (int i{0}; i < this->element.second.size(); i++) {
+        if (!this->element.second.at(i).getKey().compare(str) || !this->element.second.at(i).getValue().compare(str)) {
+            return i;
+        }
+    }
+
+    return docpp::CSS::CSSElement::npos;
+}
+
+int docpp::CSS::CSSElement::size() const {
+    return this->element.second.size();
+}
+
+void docpp::CSS::CSSElement::swap(const int index1, const int index2) {
+    if (index1 < 0 || index1 >= this->element.second.size() || index2 < 0 || index2 >= this->element.second.size()) {
+        throw std::out_of_range("Index out of range");
+    }
+
+    std::swap(this->element.second[index1], this->element.second[index2]);
+}
+
+void docpp::CSS::CSSElement::swap(const CSSProperty& property1, const CSSProperty& property2) {
+    this->swap(this->find(property1), this->find(property2));
+}
+
 std::string docpp::CSS::CSSElement::get(const int formatting) const {
     std::string ret{};
 
diff --git a/tests/test.cpp b/tests/test.cpp
index 0c1d323..393bbaa 100644
--- a/tests/test.cpp
+++ b/tests/test.cpp
@@ -218,7 +218,27 @@ SCENARIO("Test HTML", "[HTML]") {
         REQUIRE(section.get() == "<html><p>Test 1</p><p>Test 3</p><p>Test 4</p><p>Test 5</p></html>");
     };
 
-    std::vector<void (*)()> tests{test1, test2, test3, test4, test5, test6, test7, test8, test9, test10, test11, test12, test13};
+    auto test14 = []() {
+        docpp::CSS::CSSElement element{"p", {{"color", "red"}, {"font-size", "16px"}, {"font-family", "Arial"}}};
+
+        const int red = element.find("color");
+
+        REQUIRE(red != docpp::CSS::CSSElement::npos);
+
+        const int blue = element.find("blue");
+
+        REQUIRE(blue == docpp::CSS::CSSElement::npos);
+
+        element.erase(red);
+
+        REQUIRE(element.get() == "p {font-size: 16px;font-family: Arial;}");
+
+        element.insert(red, docpp::CSS::CSSProperty("color", "red"));
+
+        REQUIRE(element.get() == "p {color: red;font-size: 16px;font-family: Arial;}");
+    };
+
+    std::vector<void (*)()> tests{test1, test2, test3, test4, test5, test6, test7, test8, test9, test10, test11, test12, test13, test14};
 
     for (const auto& test : tests) {
         test();