Improve center label and details box styling

- Move center label from ECharts canvas to HTML overlay for better font rendering
- Style ₽ symbol separately with lighter color (#888) and slightly smaller size (20px)
- Use tighter line height (1.0) for center label
- Remove "Детали" heading from details box, use total as header
- Remove top border from details header
- Increase header font sizes to 20px
- Add more whitespace above "Top Items:"

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app.js

@@ -1,10 +1,21 @@
-// Format RUB amount: no decimals, thin space (U+2009) as thousands separator
+// Format RUB amount: no decimals, narrow no-break space as thousands separator
 function formatRUB(amount) {
     return Math.round(amount)
         .toLocaleString('ru-RU')
         .replace(/\u00a0/g, '\u202F');
 }
 
+// Update HTML center label (month in gray, category optional, amount in black)
+function updateCenterLabel(month, amount, category = null) {
+    const labelEl = document.getElementById('center-label');
+    if (!labelEl) return;
+
+    labelEl.querySelector('.center-month').textContent = month;
+    labelEl.querySelector('.center-category').textContent = category || '';
+    labelEl.querySelector('.center-amount-num').textContent = formatRUB(amount);
+    labelEl.querySelector('.center-rub').textContent = '\u202F₽';
+}
+
 // Initialize the chart
 const chartDom = document.getElementById('chart-container');
 const myChart = echarts.init(chartDom);
@@ -50,13 +61,8 @@ function navigateToHistoryState(state) {
     const russianMonth = getRussianMonthName(document.getElementById('month-select').value);
     option.series.data = state.data;
 
-    if (state.contextName) {
-        option.graphic.elements[0].style.text = `${russianMonth}\n${state.contextName}\n${formatRUB(state.total)}\u202F₽`;
-    } else {
-        option.graphic.elements[0].style.text = russianMonth + '\n' + formatRUB(state.total) + '\u202F₽';
-    }
-
     myChart.setOption(option, { replaceMerge: ['series'] });
+    updateCenterLabel(russianMonth, state.total, state.contextName);
     setupHoverEvents({ total: state.total, data: state.data }, state.contextName);
 
     // Restore drill path and update mini-charts
@@ -705,22 +711,7 @@ function renderChart(data) {
             }
         },
         graphic: {
-            elements: [
+            elements: []  // Center label is now HTML overlay
-                {
-                    type: 'text',
-                    left: 'center',
-                    top: 'middle',
-                    z: 100,
-                    style: {
-                        text: russianMonth + '\n' + formatRUB(sunburstData.total) + '\u202F₽',
-                        fontFamily: '-apple-system, BlinkMacSystemFont, "SF Pro", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif',
-                        fontWeight: 'bold',
-                        fontSize: 18,
-                        textAlign: 'left',
-                        fill: '#000'
-                    }
-                }
-            ]
         }
     };
     
@@ -914,9 +905,8 @@ function renderChart(data) {
 
             // Update the center text to show the drilled-down category
             const russianMonth = getRussianMonthName(document.getElementById('month-select').value);
-            option.graphic.elements[0].style.text = `${russianMonth}\n${params.name}\n${formatRUB(params.value)}\u202F₽`;
-
             myChart.setOption(option, { replaceMerge: ['series'] });
+            updateCenterLabel(russianMonth, params.value, params.name);
 
             // Update hover events with the new data structure, passing the drilled-down name
             setupHoverEvents({ total: params.value, data: newData }, params.name);
@@ -927,7 +917,10 @@ function renderChart(data) {
     });
     
     myChart.setOption(option);
-    
+
+    // Update HTML center label
+    updateCenterLabel(russianMonth, sunburstData.total);
+
     // Add click handler for the center to go back in history
     const zr = myChart.getZr();
     zr.on('click', function(params) {
@@ -1685,11 +1678,6 @@ async function selectMonth(index) {
 
         // Update the total amount in the center text
         const russianMonth = getRussianMonthName(month);
-        if (targetName) {
-            option.graphic.elements[0].style.text = `${russianMonth}\n${targetName}\n${formatRUB(targetTotal)}\u202F₽`;
-        } else {
-            option.graphic.elements[0].style.text = russianMonth + '\n' + formatRUB(targetTotal) + '\u202F₽';
-        }
 
         myChart.setOption({
             series: [{
@@ -1698,13 +1686,14 @@ async function selectMonth(index) {
                 layoutAnimation: true,
                 animationDuration: 500,
                 animationEasing: 'cubicInOut'
-            }],
+            }]
-            graphic: option.graphic
         }, {
             lazyUpdate: false,
             silent: false
         });
 
+        updateCenterLabel(russianMonth, targetTotal, targetName);
+
         // Update hover events
         setupHoverEvents({ total: targetTotal, data: targetData }, targetName);
 
@@ -1745,7 +1734,7 @@ function updateMonthNavigator() {
 // Initialize the visualization
 async function initVisualization() {
     await loadAvailableMonths();
-    
+
     // Ensure the chart is properly sized on initial load
     myChart.resize();
 }
@@ -1780,9 +1769,7 @@ function adjustChartSize() {
 
     // Update chart center position
     option.series.center = [`${centerPosition}%`, '50%'];
-    option.graphic.elements[0].left = 'center';
+
-    option.graphic.elements[0].top = 'middle';
-    
     myChart.setOption(option);
 }
 

index.html

@@ -21,6 +21,11 @@
         </div>
         <div class="content-wrapper">
             <div id="chart-container"></div>
+            <div id="center-label" class="center-label">
+                <div class="center-month"></div>
+                <div class="center-category"></div>
+                <div class="center-amount"><span class="center-amount-num"></span><span class="center-rub"></span></div>
+            </div>
             <button id="chart-eye-btn" class="chart-eye-btn" title="View transactions">
                 <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5">
                     <path d="M1 12s4-8 11-8 11 8 11 8-4 8-11 8-11-8-11-8z"/>
@@ -28,7 +33,6 @@
                 </svg>
             </button>
             <div id="details-box" class="details-box">
-                <h3>Детали</h3>
                 <div id="details-header" class="details-header">
                     <span class="hover-name">Hover over a segment to see details</span>
                     <span class="hover-amount"></span>

styles.css

@@ -140,6 +140,51 @@ body {
     box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
 }
 
+/* Center label overlay */
+.center-label {
+    position: absolute;
+    left: 35%; /* Half of chart-container width (70% / 2) */
+    top: 50%;
+    transform: translate(-50%, -50%);
+    text-align: left;
+    pointer-events: none;
+    font-family: -apple-system, BlinkMacSystemFont, "SF Pro", "Segoe UI", system-ui, sans-serif;
+    z-index: 10;
+}
+
+.center-month {
+    font-size: 18px;
+    font-weight: 400;
+    color: #666;
+    line-height: 1.0;
+}
+
+.center-category {
+    font-size: 18px;
+    font-weight: 600;
+    color: #333;
+    line-height: 1.0;
+}
+
+.center-category:empty {
+    display: none;
+}
+
+.center-amount {
+    font-size: 22px;
+    font-weight: 700;
+    line-height: 1.0;
+}
+
+.center-amount-num {
+    color: #000;
+}
+
+.center-rub {
+    color: #888;
+    font-size: 20px;
+}
+
 /* Override ECharts default pointer cursor - only eye button should have pointer */
 #chart-container canvas {
     cursor: default !important;
@@ -174,7 +219,7 @@ body {
 }
 
 #details-box h4 {
-    margin: 10px 0 5px;
+    margin: 18px 0 5px;
     color: #555;
     font-size: 14px;
 }
@@ -186,7 +231,6 @@ body {
     margin-bottom: 20px;
     padding: 10px 0;
     border-bottom: 1px solid #eee;
-    border-top: 1px solid #eee;
 }
 
 .hover-name {
@@ -196,11 +240,11 @@ body {
     flex: 1;
     display: flex;
     align-items: center;
-    font-size: 16px;
+    font-size: 20px;
 }
 
 .hover-amount {
-    font-size: 18px;
+    font-size: 20px;
     color: #0066cc;
     font-weight: bold;
     margin-left: 10px;