feat: add bilibili diagram echarts and improve style

assets/css/_mermaid/sequence.scss

@@ -0,0 +1,96 @@
+.actor {
+  stroke: $actorBorder;
+  fill: $actorBkg;
+}
+
+text.actor {
+  fill: $actorTextColor;
+  stroke: none;
+}
+
+.actor-line {
+  stroke: $actorLineColor;
+}
+
+.messageLine0 {
+  stroke-width: 1.5;
+  stroke-dasharray: '2 2';
+  stroke: $signalColor;
+}
+
+.messageLine1 {
+  stroke-width: 1.5;
+  stroke-dasharray: '2 2';
+  stroke: $signalColor;
+}
+
+#arrowhead {
+  fill: $signalColor;
+}
+
+.sequenceNumber {
+  fill: $sequenceNumberColor;
+}
+
+#sequencenumber {
+  fill: $signalColor;
+}
+
+#crosshead path {
+  fill: $signalColor !important;
+  stroke: $signalColor !important;
+}
+
+.messageText {
+  fill: $signalTextColor;
+  stroke: none;
+}
+
+.labelBox {
+  stroke: $labelBoxBorderColor;
+  fill: $labelBoxBkgColor;
+}
+
+.labelText {
+  fill: $labelTextColor;
+  stroke: none;
+}
+
+.loopText {
+  fill: $loopTextColor;
+  stroke: none;
+}
+
+.loopLine {
+  stroke-width: 2;
+  stroke-dasharray: '2 2';
+  stroke: $labelBoxBorderColor;
+}
+
+.note {
+  //stroke: #decc93;
+  stroke: $noteBorderColor;
+  fill: $noteBkgColor;
+}
+
+.noteText {
+  fill: black;
+  stroke: none;
+  font-family: 'trebuchet ms', verdana, arial;
+  font-size: 14px;
+}
+
+.activation0 {
+  fill: $activationBkgColor;
+  stroke: $activationBorderColor;
+}
+
+.activation1 {
+  fill: $activationBkgColor;
+  stroke: $activationBorderColor;
+}
+
+.activation2 {
+  fill: $activationBkgColor;
+  stroke: $activationBorderColor;
+}