explanation

lib/data/default_deck.dart

@@ -17,18 +17,21 @@ class DefaultDeck {
         prompt: 'What is the capital city of Australia?',
         answers: ['Sydney', 'Melbourne', 'Canberra', 'Perth'],
         correctAnswerIndices: [2],
+        explanation: 'Canberra was chosen as the capital in 1908 as a compromise between Sydney and Melbourne.',
       ),
       Question(
         id: 'gk_2',
         prompt: 'Which planet is known as the Red Planet?',
         answers: ['Venus', 'Mars', 'Jupiter', 'Saturn'],
         correctAnswerIndices: [1],
+        explanation: 'Mars appears red due to iron oxide (rust) on its surface.',
       ),
       Question(
         id: 'gk_3',
         prompt: 'What is the largest ocean on Earth?',
         answers: ['Atlantic Ocean', 'Indian Ocean', 'Arctic Ocean', 'Pacific Ocean'],
         correctAnswerIndices: [3],
+        explanation: 'The Pacific Ocean covers about 63 million square miles and is larger than all of Earth\'s land area combined.',
       ),
       Question(
         id: 'gk_4',
@@ -203,6 +206,7 @@ class DefaultDeck {
         prompt: 'What is the capital city of Australia?',
         answers: ['Sydney', 'Melbourne', 'Canberra', 'Perth'],
         correctAnswerIndices: [2],
+        explanation: 'Canberra was chosen as the capital in 1908 as a compromise between Sydney and Melbourne.',
         consecutiveCorrect: 3,
         isKnown: true,
         priorityPoints: 0,
@@ -216,6 +220,7 @@ class DefaultDeck {
         prompt: 'Which planet is known as the Red Planet?',
         answers: ['Venus', 'Mars', 'Jupiter', 'Saturn'],
         correctAnswerIndices: [1],
+        explanation: 'Mars appears red due to iron oxide (rust) on its surface.',
         consecutiveCorrect: 3,
         isKnown: true,
         priorityPoints: 0,
@@ -227,6 +232,7 @@ class DefaultDeck {
       Question(
         id: 'gk_3',
         prompt: 'What is the largest ocean on Earth?',
+        explanation: 'The Pacific Ocean covers about 63 million square miles and is larger than all of Earth\'s land area combined.',
         answers: ['Atlantic Ocean', 'Indian Ocean', 'Arctic Ocean', 'Pacific Ocean'],
         correctAnswerIndices: [3],
         consecutiveCorrect: 3,