增加比赛倒计时的功能

static/src/css/contest/countdown.css

@@ -0,0 +1,14 @@
+#timer {
+    margin: 20px auto;
+}
+.timer-section {
+    display: inline-block;
+}
+.timer-section span {
+    background-color: #ffffff;
+    padding: 5px 4px;
+    border-radius: 5px;
+}
+.time {
+    font-weight: bold;
+}

static/src/css/oj.css

@@ -2,6 +2,7 @@
 @import url("bootstrap/todc-bootstrap.min.css");
 @import url("codeMirror/codemirror.css");
 @import url("global.css");
+@import url("contest/countdown.css");
 
 #language-selector {
     width: 130px;