CSS3圆角气泡框，评论对话框

<title>CSS3圆角气泡框，评论对话框</title>
<style>
body {
    padding:0; 
    margin:0; 
    font:1em/1.4 Cambria, Georgia, sans-serif; 
    color:#333; 
    background:#fff;
}

a:link,
a:visited {
    border-bottom:1px solid #c55500; 
    text-decoration:none;
    color:#c55500; 
}

a:visited {
    border-bottom:1px solid #730800; 
    color:#730800;
}

a:hover,
a:focus,
a:active {
    border:0; 
    color:#fff; 
    background:#c55500;
}

a:visited:hover,
a:visited:focus,
a:visited:active {
    color:#fff; 
    background:#730800;
}

#container {
    width:500px; 
    padding:0 0 50px; 
    margin:0 auto;
}

h1 {
    margin:1em 0 0; 
    font-size:2.5em; 
    font-weight:normal; 
    line-height:1.2; 
    text-align:center;
}

h2 {
    margin:0.5em 0 1.5em; 
    font-size:1.25em; 
    font-weight:normal; 
    font-style:italic; 
    text-align:center;
}

p {
    margin:1em 0;
}

.content h2 {
    margin:2em 0 0.75em; 
    font-size:2em; 
    font-weight:bold; 
    font-style:normal; 
    text-align:left;
}

blockquote {
    margin:1em 0;
}

blockquote p {
    margin:0; 
    font-size:2em;
}

.follow {
    clear:both; 
    margin-top:2em; 
    font-size:1.125em;
}

.follow span {
    font-weight:bold;
}

.content {
    position:relative;
    z-index:1;
}
.triangle-isosceles {
    position:relative;
    padding:15px;
    margin:1em 0 3em;
    color:#000;
    background:#f3961c; /* default background for browsers without gradient support */
    background:-webkit-gradient(linear, 0 0, 0 100%, from(#f9d835), to(#f3961c));
    background:-moz-linear-gradient(#f9d835, #f3961c);
    background:-o-linear-gradient(#f9d835, #f3961c);
    background:linear-gradient(#f9d835, #f3961c);
    -webkit-border-radius:10px;
    -moz-border-radius:10px;
    border-radius:10px;
}
.triangle-isosceles.top {
    background:-webkit-gradient(linear, 0 0, 0 100%, from(#f3961c), to(#f9d835));
    background:-moz-linear-gradient(#f3961c, #f9d835);
    background:-o-linear-gradient(#f3961c, #f9d835);
    background:linear-gradient(#f3961c, #f9d835);
}

.triangle-isosceles.left {
    margin-left:50px;
    background:#f3961c;
}
.triangle-isosceles.right {
    margin-right:50px;
    background:#f3961c;
}
.triangle-isosceles:after {
    content:"";
    position:absolute;
    bottom:-15px;
    left:50px;
    border-width:15px 15px 0; 
    border-style:solid;
    border-color:#f3961c transparent;
    display:block; 
    width:0;
}
.triangle-isosceles.top:after {
    top:-15px;
    right:50px;
    bottom:auto;
    left:auto;
    border-width:0 15px 15px;
    border-color:#f3961c transparent;
}
.triangle-isosceles.left:after {
    top:16px;
    left:-50px;
    bottom:auto;
    border-width:10px 50px 10px 0;
    border-color:transparent #f3961c;
}
.triangle-isosceles.right:after {
    top:16px; /* controls vertical position */
    right:-50px;
    bottom:auto;
    left:auto;
    border-width:10px 0 10px 50px;
    border-color:transparent #f3961c;
}

.triangle-right {
    position:relative;
    padding:15px;
    margin:1em 0 3em;
    color:#fff;
    background:#075698; 
    /* css3 */
    background:-webkit-gradient(linear, 0 0, 0 100%, from(#2e88c4), to(#075698));
    background:-moz-linear-gradient(#2e88c4, #075698);
    background:-o-linear-gradient(#2e88c4, #075698);
    background:linear-gradient(#2e88c4, #075698);
    -webkit-border-radius:10px;
    -moz-border-radius:10px;
    border-radius:10px;
}
.triangle-right.top {
    background:-webkit-gradient(linear, 0 0, 0 100%, from(#075698), to(#2e88c4));
    background:-moz-linear-gradient(#075698, #2e88c4);
    background:-o-linear-gradient(#075698, #2e88c4);
    background:linear-gradient(#075698, #2e88c4);
}
.triangle-right.left {
    margin-left:40px;
    background:#075698;
}
.triangle-right.right {
    margin-right:40px;
    background:#075698;
}
.triangle-right:after {
    content:"";
    position:absolute;
    bottom:-20px; /* value = - border-top-width - border-bottom-width */
    left:50px; /* controls horizontal position */
    border-width:20px 0 0 20px; /* vary these values to change the angle of the vertex */
    border-style:solid;
    border-color:#075698 transparent; 
    display:block; 
    width:0;
}

.triangle-right.top:after {
    top:-20px; /* value = - border-top-width - border-bottom-width */
    right:50px; /* controls horizontal position */
    bottom:auto;
    left:auto;
    border-width:20px 20px 0 0; /* vary these values to change the angle of the vertex */
    border-color:transparent #075698; 
}

.triangle-right.left:after {
    top:16px; 
    left:-40px; /* value = - border-left-width - border-right-width */
    bottom:auto;
    border-width:15px 40px 0 0; /* vary these values to change the angle of the vertex */
    border-color:transparent #075698; 
}
.triangle-right.right:after {
    top:16px; 
    right:-40px; /* value = - border-left-width - border-right-width */
    bottom:auto;
    left:auto;
    border-width:15px 0 0 40px; /* vary these values to change the angle of the vertex */
    border-color:transparent #075698 ; 
}
.triangle-obtuse {
    position:relative;
    padding:15px;
    margin:1em 0 3em;
    color:#fff;
    background:#c81e2b;
    /* css3 */
    background:-webkit-gradient(linear, 0 0, 0 100%, from(#f04349), to(#c81e2b));
    background:-moz-linear-gradient(#f04349, #c81e2b);
    background:-o-linear-gradient(#f04349, #c81e2b);
    background:linear-gradient(#f04349, #c81e2b);
    -webkit-border-radius:10px;
    -moz-border-radius:10px;
    border-radius:10px;
}
.triangle-obtuse.top {
    background:-webkit-gradient(linear, 0 0, 0 100%, from(#c81e2b), to(#f04349));
    background:-moz-linear-gradient(#c81e2b, #f04349);
    background:-o-linear-gradient(#c81e2b, #f04349);
    background:linear-gradient(#c81e2b, #f04349);
}

.triangle-obtuse.left {
    margin-left:50px;
    background:#c81e2b;
}
.triangle-obtuse.right {
    margin-right:50px;
    background:#c81e2b;
}
.triangle-obtuse:before {
    content:"";
    position:absolute;
    bottom:-20px; /* value = - border-top-width - border-bottom-width */
    left:60px; /* controls horizontal position */
    border:0;
    border-right-width:30px; /* vary this value to change the angle of the vertex */
    border-bottom-width:20px; /* vary this value to change the height of the triangle. must be equal to the corresponding value in :after */
    border-style:solid;
    border-color:transparent #c81e2b;
    /* reduce the damage in FF3.0 */
    display:block; 
    width:0;
}
.triangle-obtuse:after {
    content:"";
    position:absolute;
    bottom:-20px; /* value = - border-top-width - border-bottom-width */
    left:80px; /* value = (:before's left) + (:before's border-right/left-width)  - (:after's border-right/left-width) */
    border:0;
    border-right-width:10px; /* vary this value to change the angle of the vertex */
    border-bottom-width:20px; /* vary this value to change the height of the triangle. must be equal to the corresponding value in :before */
    border-style:solid;
    border-color:transparent #fff;
    /* reduce the damage in FF3.0 */
    display:block; 
    width:0;
}

.triangle-obtuse.top:before {
    top:-20px; /* value = - border-top-width - border-bottom-width */
    bottom:auto;
    left:auto;
    right:60px; /* controls horizontal position */
    border:0;
    border-left-width:30px; /* vary this value to change the width of the triangle */
    border-top-width:20px; 
    border-color:transparent #c81e2b;
}

.triangle-obtuse.top:after {
    top:-20px; /* value = - border-top-width - border-bottom-width */
    bottom:auto;
    left:auto;
    right:80px; /* value = (:before's right) + (:before's border-right/left-width)  - (:after's border-right/left-width) */
    border-width:0;
    border-left-width:10px;
    border-top-width:20px; 
    border-color:transparent #fff;
}
.triangle-obtuse.left:before {
    top:15px; /* controls vertical position */
    bottom:auto;
    left:-50px; 
    border:0;
    border-bottom-width:30px;
    border-left-width:50px;
    border-color:#c81e2b transparent;
}
.triangle-obtuse.left:after {
    top:35px;
    bottom:auto;
    left:-50px;
    border:0;
    border-bottom-width:10px;
    border-left-width:50px;
    border-color:#fff transparent;
}

.triangle-obtuse.right:before {
    top:15px;
    bottom:auto;
    left:auto;
    right:-50px;
    border:0;
    border-bottom-width:30px; /* vary this value to change the height of the triangle */
    border-right-width:50px;
    border-color:#c81e2b transparent;
}

.triangle-obtuse.right:after {
    top:35px; 
    bottom:auto;
    right:-50px; /* value = - border-left-width - border-right-width */
    left:auto;
    border:0;
    border-bottom-width:10px; /* vary this value to change the height of the triangle */
    border-right-width:50px;
    border-color:#fff transparent;
}
.triangle-border {
    position:relative;
    padding:15px;
    margin:1em 0 3em;
    border:5px solid #5a8f00;
    color:#333;
    background:#fff;
    /* css3 */
    -webkit-border-radius:10px;
    -moz-border-radius:10px;
    border-radius:10px;
}
.triangle-border.left {
    margin-left:30px;
}

.triangle-border.right {
    margin-right:30px;
}
.triangle-border:before {
    content:"";
    position:absolute;
    bottom:-20px; /* value = - border-top-width - border-bottom-width */
    left:40px; /* controls horizontal position */
    border-width:20px 20px 0;
    border-style:solid;
    border-color:#5a8f00 transparent;
    display:block; 
    width:0;
}

/* creates the smaller  triangle */
.triangle-border:after {
    content:"";
    position:absolute;
    bottom:-13px; /* value = - border-top-width - border-bottom-width */
    left:47px; 
    border-width:13px 13px 0;
    border-style:solid;
    border-color:#fff transparent;
    display:block; 
    width:0;
}
.triangle-border.top:before {
    top:-20px; /* value = - border-top-width - border-bottom-width */
    bottom:auto;
    left:auto;
    right:40px; /* controls horizontal position */
    border-width:0 20px 20px;
}

/* creates the smaller  triangle */
.triangle-border.top:after {
    top:-13px; /* value = - border-top-width - border-bottom-width */
    bottom:auto;
    left:auto;
    right:47px; /* value = (:before right) + (:before border-right) - (:after border-right) */
    border-width:0 13px 13px;
}
.triangle-border.left:before {
    top:10px; /* controls vertical position */
    bottom:auto;
    left:-30px; /* value = - border-left-width - border-right-width */
    border-width:15px 30px 15px 0;
    border-color:transparent #5a8f00;
}

/* creates the smaller  triangle */
.triangle-border.left:after {
    top:16px; /* value = (:before top) + (:before border-top) - (:after border-top) */
    bottom:auto;
    left:-21px; /* value = - border-left-width - border-right-width */
    border-width:9px 21px 9px 0;
    border-color:transparent #fff;
}

/* creates the larger triangle */
.triangle-border.right:before {
    top:10px; /* controls vertical position */
    bottom:auto;
    left:auto;
    right:-30px; /* value = - border-left-width - border-right-width */
    border-width:15px 0 15px 30px;
    border-color:transparent #5a8f00;
}

/* creates the smaller  triangle */
.triangle-border.right:after {
    top:16px; /* value = (:before top) + (:before border-top) - (:after border-top) */
    bottom:auto;
    left:auto;
    right:-21px; /* value = - border-left-width - border-right-width */
    border-width:9px 0 9px 21px;
    border-color:transparent #fff;
}
.example-commentheading:before {
    content:"";
    position:absolute;
    top:9px;
    left:-25px;
    width:15px;
    height:10px;
    background:#b513af;
    /* css3 */
    -webkit-border-radius:3px;
    -moz-border-radius:3px;
    border-radius:3px;
}

/* creates the triangle */
.example-commentheading:after {
    content:"";
    position:absolute;
    top:15px;
    left:-19px;
    border:4px solid transparent;
    border-left-color:#b513af;
    /* reduce the damage in FF3.0 */
    display:block; 
    width:0;
}

.example-right {
    position:relative;
    padding:15px 30px;
    margin:0;
    color:#fff;
    background:#5a8f00; /* default background for browsers without gradient support */
    /* css3 */
    background:-webkit-gradient(linear, 0 0, 0 100%, from(#b8db29), to(#5a8f00));
    background:-moz-linear-gradient(#b8db29, #5a8f00);
    background:-o-linear-gradient(#b8db29, #5a8f00);
    background:linear-gradient(#b8db29, #5a8f00);
    -webkit-border-radius:10px;
    -moz-border-radius:10px;
    border-radius:10px;
}
.example-right + p {margin:15px 0 2em 85px; font-style:italic;}
.example-right:after {
    content:"";
    position:absolute;
    bottom:-50px;
    left:50px;
    border-width:0 20px 50px 0px;
    border-style:solid;
    border-color:transparent #5a8f00;
    /* reduce the damage in FF3.0 */
    display:block; 
    width:0;
}
.example-obtuse {
    position:relative;
    padding:15px 30px;
    margin:0;
    color:#000;
    background:#f3961c; /* default background for browsers without gradient support */
    /* css3 */
    background:-webkit-gradient(linear, 0 0, 0 100%, from(#f9d835), to(#f3961c));
    background:-moz-linear-gradient(#f9d835, #f3961c);
    background:-o-linear-gradient(#f9d835, #f3961c);
    background:linear-gradient(#f9d835, #f3961c);
    /* Using longhand to avoid inconsistencies between Safari 4 and Chrome 4 */
    -webkit-border-top-left-radius:25px 50px;
    -webkit-border-top-right-radius:25px 50px;
    -webkit-border-bottom-right-radius:25px 50px;
    -webkit-border-bottom-left-radius:25px 50px;
    -moz-border-radius:25px / 50px;
    border-radius:25px / 50px;
}

.example-obtuse + p {margin:10px 150px 2em 0; text-align:right; font-style:italic;}
.example-obtuse:before {
    content:"";
    position:absolute;
    bottom:-30px;
    right:80px;
    border-width:0 0 30px 50px;
    border-style:solid;
    border-color:transparent #f3961c;
    /* reduce the damage in FF3.0 */
    display:block; 
    width:0;
}

/* creates the smaller triangle */
.example-obtuse:after {
    content:"";
    position:absolute;
    bottom:-30px;
    right:110px; 
    border-width:0 0 30px 20px;
    border-style:solid;
    border-color:transparent #fff;
    /* reduce the damage in FF3.0 */
    display:block; 
    width:0;
}
.example-twitter {
    position:relative;
    padding:15px;
    margin:100px 0 0.5em;
    color:#333;
    background:#eee;
    /* css3 */
    -webkit-border-radius:10px;
    -moz-border-radius:10px;
    border-radius:10px;
}

.example-twitter p {font-size:28px; line-height:1.25em;}
.example-twitter:before {
    content:url(twitter-logo.gif);
    position:absolute;
    top:-60px;
    left:0;
    width:155px;
    height:36px;
    /* reduce the damage in FF3.0 */
    display:block; 
}
.example-twitter:after {
    content:"";
    position:absolute;
    top:-30px;
    left:50px;
    border:15px solid transparent;
    border-bottom-color:#eee;
    /* reduce the damage in FF3.0 */
    display:block; 
    width:0;
}
.example-twitter + p {padding-left:15px; font:14px Arial, sans-serif;}
.example-number {
    position:relative;
    width:200px;
    height:200px;
    margin:50px 0 200px;
    text-align:center;
    font:140px/200px Arial, sans-serif;
    color:#fff;
    background:#C91F2C;
}
.example-number:before {
    content:"";
    position:absolute;
    bottom:-140px;
    right:0;
    border-width:0 0 140px 140px;
    border-style:solid;
    border-color:transparent #C91F2C;
}
.example-number:after {
    content:"";
    position:absolute;
    bottom:-140px;
    right:85px; 
    border-width:0 0 140px 55px;
    border-style:solid;
    border-color:transparent #fff;
}
.pinched {
    position:relative;
    padding:15px;
    margin:50px 0 3em;
    text-align:center;
    color:#fff;
    background:#333; 
    /* css3 */
    -webkit-border-radius:10px;
    -moz-border-radius:10px;
    border-radius:10px;
}
.pinched:before {
    content:"";
    position:absolute;
    top:-20px;
    left:50%;
    width:100px;
    height:20px;
    margin:0 0 0 -50px;
    background:#333;
}
.pinched:after {
    content:"";
    position:absolute;
    top:-20px;
    left:0;
    width:50%;
    height:20px;
    background:#fff;
    /* css3 */
    -webkit-border-bottom-right-radius:15px;
    -moz-border-radius-bottomright:15px;
    border-bottom-right-radius:15px;
}
.pinched > :first-child:before {
    content:""; 
    position:absolute; 
    top:-20px; 
    right:0; 
    width:50%; 
    height:20px; 
    background:#fff;
    /* css3 */
    -webkit-border-bottom-left-radius:15px;
    -moz-border-radius-bottomleft:15px;
    border-bottom-left-radius:15px;
}
.oval-speech {
    position:relative;
    width:270px;
    padding:50px 40px;
    margin:1em auto 50px;
    text-align:center;
    color:#fff; 
    background:#5a8f00;
    /* css3 */
    background:-webkit-gradient(linear, 0 0, 0 100%, from(#b8db29), to(#5a8f00));
    background:-moz-linear-gradient(#b8db29, #5a8f00);
    background:-o-linear-gradient(#b8db29, #5a8f00);
    background:linear-gradient(#b8db29, #5a8f00);
    -webkit-border-top-left-radius:220px 120px;
    -webkit-border-top-right-radius:220px 120px;
    -webkit-border-bottom-right-radius:220px 120px;
    -webkit-border-bottom-left-radius:220px 120px;
    -moz-border-radius:220px / 120px;
    border-radius:220px / 120px;
}

.oval-speech p {font-size:1.25em;}
.oval-speech:before {
    content:"";
    position:absolute;
    z-index:-1;
    bottom:-30px;
    right:50%;
    height:30px;
    border-right:60px solid #5a8f00;
    background:#5a8f00; /* need this for webkit - bug in handling of border-radius */
    /* css3 */
    -webkit-border-bottom-right-radius:80px 50px;
    -moz-border-radius-bottomright:80px 50px;
    border-bottom-right-radius:80px 50px;
    /* using translate to avoid undesired appearance in CSS2.1-capabable but CSS3-incapable browsers */
    -webkit-transform:translate(0, -2px);
    -moz-transform:translate(0, -2px);
    -ms-transform:translate(0, -2px);
    -o-transform:translate(0, -2px);
    transform:translate(0, -2px);
}

/* creates part of the curved pointy bit */
.oval-speech:after {
    content:"";
    position:absolute;
    z-index:-1;
    bottom:-30px;
    right:50%;
    width:60px;
    height:30px;
    background:#fff;
    /* css3 */
    -webkit-border-bottom-right-radius:40px 50px; 
    -moz-border-radius-bottomright:40px 50px; 
    border-bottom-right-radius:40px 50px; 
    /* using translate to avoid undesired appearance in CSS2.1-capabable but CSS3-incapable browsers */
    -webkit-transform:translate(-30px, -2px);
    -moz-transform:translate(-30px, -2px);
    -ms-transform:translate(-30px, -2px);
    -o-transform:translate(-30px, -2px);
    transform:translate(-30px, -2px);
}
.oval-thought {
    position:relative;
    width:270px;
    padding:50px 40px;
    margin:1em auto 80px;
    text-align:center;
    color:#fff; 
    background:#075698;
    /* css3 */
    background:-webkit-gradient(linear, 0 0, 0 100%, from(#2e88c4), to(#075698));
    background:-moz-linear-gradient(#2e88c4, #075698);
    background:-o-linear-gradient(#2e88c4, #075698);
    background:linear-gradient(#2e88c4, #075698);
    /*
    NOTES:
    -webkit-border-radius:220px 120px; // produces oval in safari 4 and chrome 4
    -webkit-border-radius:220px / 120px; // produces oval in chrome 4 (again!) but not supported in safari 4
    Not correct application of the current spec, therefore, using longhand to avoid future problems with webkit corrects this
    */
    -webkit-border-top-left-radius:220px 120px;
    -webkit-border-top-right-radius:220px 120px;
    -webkit-border-bottom-right-radius:220px 120px;
    -webkit-border-bottom-left-radius:220px 120px;
    -moz-border-radius:220px / 120px;
    border-radius:220px / 120px;
}

.oval-thought p {font-size:1.25em;}

/* creates the larger circle */
.oval-thought:before {
    content:"";
    position:absolute;
    bottom:-20px;
    left:50px;
    width:30px;
    height:30px;
    background:#075698;
    /* css3 */
    -webkit-border-radius:30px;
    -moz-border-radius:30px;
    border-radius:30px;
}

/* creates the smaller circle */
.oval-thought:after {
    content:"";
    position:absolute;
    bottom:-30px;
    left:30px;
    width:15px;
    height:15px;
    background:#075698;
    /* css3 */
    -webkit-border-radius:15px;
    -moz-border-radius:15px;
    border-radius:15px;
}
.oval-quotes {
    position:relative;
    width:400px;
    height:350px;
    margin:2em auto 10px;
    color:#000;
    background:#ffed26;
    /* css3 */
    /*
    NOTES:
    -webkit-border-radius:Apx Bpx; // produces oval in safari 4 and chrome 4
    -webkit-border-radius:Apx / Bpx; // produces oval in chrome 4 (again!) but not supported in safari 4
    Not correct application of the current spec, therefore, using longhand to avoid future problems with webkit corrects this
    */
    -webkit-border-top-left-radius:400px 350px;
    -webkit-border-top-right-radius:400px 350px;
    -webkit-border-bottom-right-radius:400px 350px;
    -webkit-border-bottom-left-radius:400px 350px;
    -moz-border-radius:400px / 350px;
    border-radius:400px / 350px;
}

/* creates opening quotation mark */
.oval-quotes:before {
    content:"201C"; 
    position:absolute; 
    z-index:1; 
    top:20px; 
    left:20px; 
    font:80px/1 Georgia, serif;
    color:#ffed26;
}

/* creates closing quotation mark */
.oval-quotes:after {
    content:"201D"; 
    position:absolute; 
    z-index:1; 
    bottom:0; 
    right:20px; 
    font:80px/0.25 Georgia, serif;
    color:#ffed26;
}

.oval-quotes p {
    width:250px;
    height:250px;
    padding:50px 0 0;
    margin:0 auto;
    text-align:center;
    font-size:35px;
}

/* creates smaller curve */
.oval-quotes p:before {
    content:"";
    position:absolute;
    z-index:-1;
    bottom:-30px;
    right:55%;
    width:180px; /* wider than necessary to make it look a bit better in IE8 */
    height:60px;
    background:#fff; /* need this for webkit - bug in handling of border-radius */
    /* css3 */

    -webkit-border-bottom-right-radius:40px 50px; 
    -moz-border-radius-bottomright:40px 50px; 
    border-bottom-right-radius:40px 50px; 
    /* using translate to avoid undesired appearance in CSS2.1-capabable but CSS3-incapable browsers */
    -webkit-transform:translate(-30px, -2px);
    -moz-transform:translate(-30px, -2px);
    -ms-transform:translate(-30px, -2px);
    -o-transform:translate(-30px, -2px);
    transform:translate(-30px, -2px);
}

/* creates larger curve */
.oval-quotes p:after {
    content:"";
    position:absolute;
    z-index:-2;
    bottom:-30px;
    right:25%;
    height:80px;
    border-right:200px solid #ffed26;
    background:#ffed26; /* need this for webkit - bug in handling of border-radius */
    /* css3 */
    -webkit-border-bottom-right-radius:200px 100px;
    -moz-border-radius-bottomright:200px 100px;
    border-bottom-right-radius:200px 100px;
    /* using translate to avoid undesired appearance in CSS2.1-capabable but CSS3-incapable browsers */
    -webkit-transform:translate(0, -2px);
    -moz-transform:translate(0, -2px);
    -ms-transform:translate(0, -2px);
    -o-transform:translate(0, -2px);
    transform:translate(0, -2px);
    /* reduce the damage in FF3.0 */
    display:block; 
    width:0;
}

.oval-quotes + p {
    position:relative; /* part of the IE8 width compromise */
    width:150px;
    margin:0 0 2em;
    font-size:18px;
    font-weight:bold;
}
.rectangle-speech-border {
    position:relative; 
    padding:50px 15px; 
    margin:1em 0 3em;
    border:10px solid #5a8f00; 
    text-align:center; 
    color:#333;
    background:#fff; 
    /* css3 */
    -webkit-border-radius:20px;
    -moz-border-radius:20px;
    border-radius:20px;
}

/* creates larger curve */
.rectangle-speech-border:before {
    content:""; 
    position:absolute; 
    z-index:10; 
    bottom:-40px; 
    left:50px; 
    width:50px; 
    height:30px;
    border-style:solid; 
    border-width:0 10px 10px 0; 
    border-color:#5a8f00; 
    background:transparent;
    /* css3 */
    -webkit-border-bottom-right-radius:80px 50px;
    -moz-border-radius-bottomright:80px 50px;
    border-bottom-right-radius:80px 50px;
    /* reduce the damage in FF3.0 */
    display:block; 
}

/* creates smaller curve */
.rectangle-speech-border:after {
    content:""; 
    position:absolute; 
    z-index:10; 
    bottom:-40px; 
    left:50px; 
    width:20px; 
    height:30px; 
    border-style:solid; 
    border-width:0 10px 10px 0; 
    border-color:#5a8f00; 
    background:transparent;
    /* css3 */
    -webkit-border-bottom-right-radius:40px 50px; 
    -moz-border-radius-bottomright:40px 50px; 
    border-bottom-right-radius:40px 50px; 
    /* reduce the damage in FF3.0 */
    display:block; 
}

/* creates a small circle to produce a rounded point where the two curves meet */
.rectangle-speech-border > :first-child:before {
    content:""; 
    position:absolute; 
    bottom:-40px; 
    left:45px; 
    width:10px; 
    height:10px;
    background:#5a8f00;
    /* css3 */
    -webkit-border-radius:10px;
    -moz-border-radius:10px;
    border-radius:10px;
}

/* creates a white rectangle to cover part of the oval border*/
.rectangle-speech-border > :first-child:after {
    content:""; 
    position:absolute; 
    bottom:-10px; 
    left:76px; 
    width:24px; 
    height:15px; 
    background:#fff;
}
.oval-speech-border {
    position:relative; 
    padding:70px 30px;
    margin:1em auto 60px;
    border:10px solid #f3961c; 
    text-align:center;
    color:#333; 
    background:#fff;
    /* css3 */
    /*
    NOTES:
    -webkit-border-radius:240px 140px; // produces oval in safari 4 and chrome 4
    -webkit-border-radius:240px / 140px; // produces oval in chrome 4 (again!) but not supported in safari 4
    Not correct application of the current spec, therefore, using longhand to avoid future problems with webkit corrects this
    */
    -webkit-border-top-left-radius:240px 140px;
    -webkit-border-top-right-radius:240px 140px;
    -webkit-border-bottom-right-radius:240px 140px;
    -webkit-border-bottom-left-radius:240px 140px;
    -moz-border-radius:240px / 140px;
    border-radius:240px / 140px;
}

/* creates larger curve */
.oval-speech-border:before {
    content:""; 
    position:absolute; 
    z-index:2; 
    bottom:-40px; 
    right:50%; 
    width:50px; 
    height:30px;
    border-style:solid;
    border-width:0 10px 10px 0;
    border-color:#f3961c;
    margin-right:-10px;
    background:transparent;
    /* css3 */
    -webkit-border-bottom-right-radius:80px 50px;
    -moz-border-radius-bottomright:80px 50px;
    border-bottom-right-radius:80px 50px;
    /* reduce the damage in FF3.0 */
    display:block; 
}

/* creates smaller curve */
.oval-speech-border:after {
    content:""; 
    position:absolute; 
    z-index:2; 
    bottom:-40px; 
    right:50%; 
    width:20px; 
    height:31px; 
    border-style:solid;
    border-width:0 10px 10px 0;
    border-color:#f3961c;
    margin-right:20px;
    background:transparent;
    /* css3 */
    -webkit-border-bottom-right-radius:40px 50px; 
    -moz-border-radius-bottomright:40px 50px; 
    border-bottom-right-radius:40px 50px; 
    /* reduce the damage in FF3.0 */
    display:block; 
}

/* creates a small circle to produce a rounded point where the two curves meet */
.oval-speech-border > :first-child:before {
    content:""; 
    position:absolute; 
    z-index:1; 
    bottom:-40px; 
    right:50%; 
    width:10px; 
    height:10px;
    margin-right:45px;
    background:#f3961c;
    /* css3 */
    -webkit-border-radius:10px;
    -moz-border-radius:10px;
    border-radius:10px;
}

/* creates a white rectangle to cover part of the oval border*/
.oval-speech-border > :first-child:after {
    content:""; 
    position:absolute; 
    z-index:1; 
    bottom:-10px; 
    right:50%; 
    width:30px; 
    height:15px; 
    background:#fff;
}

.oval-thought-border {
    position:relative; 
    padding:70px 30px;
    margin:1em auto 80px;
    border:10px solid #c81e2b; 
    text-align:center;
    color:#333; 
    background:#fff;
    /* css3 */
    /*
    NOTES:
    -webkit-border-radius:240px 140px; // produces oval in safari 4 and chrome 4
    -webkit-border-radius:240px / 140px; // produces oval in chrome 4 (again!) but not supported in safari 4
    Not correct application of the current spec, therefore, using longhand to avoid future problems with webkit corrects this
    */
    -webkit-border-top-left-radius:240px 140px;
    -webkit-border-top-right-radius:240px 140px;
    -webkit-border-bottom-right-radius:240px 140px;
    -webkit-border-bottom-left-radius:240px 140px;
    -moz-border-radius:240px / 140px;
    border-radius:240px / 140px;
}

/* creates the larger circle */
.oval-thought-border:before {
    content:""; 
    position:absolute; 
    z-index:10; 
    bottom:-40px; 
    right:100px; 
    width:50px; 
    height:50px;
    border:10px solid #c81e2b;
    background:#fff;
    /* css3 */
    -webkit-border-radius:50px;
    -moz-border-radius:50px;
    border-radius:50px;
    /* reduce the damage in FF3.0 */
    display:block; 
}

/* creates the smaller circle */
.oval-thought-border:after {
    content:""; 
    position:absolute; 
    z-index:10; 
    bottom:-60px; 
    right:50px; 
    width:25px; 
    height:25px; 
    border:10px solid #c81e2b;
    background:#fff;
    /* css3 */
    -webkit-border-radius:25px;
    -moz-border-radius:25px;
    border-radius:25px;
    /* reduce the damage in FF3.0 */
    display:block; 
}
    </style>
    <script>
        var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-7489188-1']); _gaq.push(['_trackPageview']);
        (function () {
            var ga = document.createElement('script'); ga.async = true; ga.src = 'http://www.google-analytics.com/ga.js';
            var s = document.getElementsByTagName('script')[0];
            s.parentNode.insertBefore(ga, s);
        })();
    </script>
</head>



<body>
    <div id="container">
        <div class="content">
 
            <p class="triangle-isosceles">This only needs one HTML element.</p>
            <p class="triangle-isosceles top">For example, <code><p>[text]</p></code>.</p>
            <p class="triangle-isosceles left">But it could be any element you want.</p>
            <p class="triangle-isosceles right">The entire appearance is created only with CSS.</p>
            <p class="triangle-right">This only needs one HTML element.</p>
            <p class="triangle-right top">For example, <code><p>[text]</p></code>.</p>
            <p class="triangle-right left">But it could be any element you want.</p>
            <p class="triangle-right right">The entire appearance is created only with CSS.</p>
            <p class="triangle-obtuse">This only needs one HTML element.</p>
            <p class="triangle-obtuse top">For example, <code><p>[text]</p></code>.</p>
            <p class="triangle-obtuse left">But it could be any element you want.</p>
            <p class="triangle-obtuse right">The entire appearance is created only with CSS.</p>
            <p class="triangle-border">This only needs one HTML element.</p>
            <p class="triangle-border top">For example, <code><p>[text]</p></code>.</p>
            <p class="triangle-border left">But it could be any element you want.</p>
            <p class="triangle-border right">The entire appearance is created only with CSS.</p>
            <h2>Simple examples</h2>
            <h3 class="example-commentheading">125 comments</h3>
            <blockquote class="example-right">
                <p>Design is directed toward human beings. To design is to solve human problems by identifying them and executing the best solution.</p>
            </blockquote>
            <p>Ivan Chermayeff</p>
            <blockquote class="example-obtuse">
                <p>It’s not what you look at that matters, it’s what you see.</p>
            </blockquote>
            <p>Henry David Thoreau</p>
            <blockquote class="example-twitter" cite="http://twitter.com/necolas/status/9880187933">
                <p>Takes me longer to write up blog posts on experiments or projects than to create them in the first place.</p>
            </blockquote>
            <p><a href="http://twitter.com/necolas">@necolas</a> at <a href="http://twitter.com/necolas/status/9880187933">4:05 PM March 2nd 2010</a></p>
            <div class="example-number">57</div>
            <h2>More complex CSS3 examples</h2>
            <p>Some more experimental speech bubbles that try to limit the damage in browsers lacking the necessary CSS3 support.</p>
            <div class="pinched">
                <p><strong>It doesn’t matter what the first child element of this div is</strong>...but it does need a child element.</p>
            </div>
            <blockquote class="oval-speech">
                <p>This is a blockquote that is styled to look like a speech bubble</p>
            </blockquote>
            <blockquote class="oval-thought">
                <p>This is a blockquote that is styled to look like a thought bubble</p>
            </blockquote>
            <blockquote class="oval-quotes">
                <p>No, Donny, these men are nihilists, there’s nothing to be afraid of.</p>
            </blockquote>
            <p>Walter Sobchak</p>
            <blockquote class="rectangle-speech-border">
                <p>This is a blockquote that is styled to look like a speech bubble</p>
            </blockquote>
            <blockquote class="oval-speech-border">
                <p>This is a blockquote that is styled to look like a speech bubble</p>
            </blockquote>
            <blockquote class="oval-thought-border">
                <p>This is a blockquote that is styled to look like a thought bubble</p>
            </blockquote>
        </div>
    </div>
</body>
</html>  

运行结果后显示：

 

总结：我在ie11和Chrome上都有试过，显示是可行的，ie8我不敢保证，所以大家还是使用最新的支持html5和CSS3的浏览器吧。