How to add Glyphicons to my Flask Application without overriding my custom css?

I am trying to insert some Glyphicons to my Flask Web Application.

I added this line to the <head> of my template:

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.0/css/bootstrap.min.css">

Here is the <head> of my layout.html file, which is extended by all views in my web application:

<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css"
          integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">

    <!-- My CSS file -->
    <link rel="stylesheet" type="text/css" href="{{ url_for('static', filename='main.css') }}">
    <!-- Glyphicons -->
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">


    <!-- Text in the tab bar -->
    <title>{{ title }}</title>

    <!-- Math formulas -->
    <SCRIPT SRC='https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML'></SCRIPT>
    <SCRIPT>MathJax.Hub.Config({tex2jax: {inlineMath: [['$', '$'], ['\\(', '\\)']]}})</SCRIPT>

</head>

And I am using, for example, this line in an html file:

<a href="#"><span class="glyphicon glyphicon-question-sign"></span></a>

It works, but apparently it overrides my css file in the static folder, since all the spacing and organizations of views in my site changes. How can I add just the glyphicons I want without overriding my css file?

Solution

If you are fine with hosting bootstrap on your server as opposed to using CDN

you can download customized version of Bootstrap and include only Glyphicon to bootstrap
even better just copy glyphicon specific styles to your CSS file and it should work, for example:

@font-face {
  font-family: "Glyphicons Halflings";
  src: url("/maxcdn.bootstrapcdn.com/bootstrap/3.3.6/fonts/glyphicons-halflings-regular.eot");
  src: url("/maxcdn.bootstrapcdn.com/bootstrap/3.3.6/fonts/glyphicons-halflings-regular.eot?#iefix") format("embedded-opentype"), url("//maxcdn.bootstrapcdn.com/bootstrap/3.3.6/fonts/glyphicons-halflings-regular.woff2") format("woff2"), url("//maxcdn.bootstrapcdn.com/bootstrap/3.3.6/fonts/glyphicons-halflings-regular.woff") format("woff"), url("//maxcdn.bootstrapcdn.com/bootstrap/3.3.6/fonts/glyphicons-halflings-regular.ttf") format("truetype"), url("//maxcdn.bootstrapcdn.com/bootstrap/3.3.6/fonts/glyphicons-halflings-regular.svg#glyphicons_halflingsregular") format("svg");
}

.glyphicon {
  position: relative;
  top: 1px;
  display: inline-block;
  font-family: "Glyphicons Halflings";
  font-style: normal;
  font-weight: 400;
  line-height: 1;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.glyphicon-asterisk:before {
  content: "\002a";
}

.glyphicon-plus:before {
  content: "\002b";
}

.glyphicon-euro:before,
.glyphicon-eur:before {
  content: "\20ac";
}

.glyphicon-minus:before {
  content: "\2212";
}

.glyphicon-cloud:before {
  content: "\2601";
}

.glyphicon-envelope:before {
  content: "\2709";
}

.glyphicon-pencil:before {
  content: "\270f";
}

.glyphicon-glass:before {
  content: "\e001";
}

.glyphicon-music:before {
  content: "\e002";
}

.glyphicon-search:before {
  content: "\e003";
}

.glyphicon-heart:before {
  content: "\e005";
}

.glyphicon-star:before {
  content: "\e006";
}

.glyphicon-star-empty:before {
  content: "\e007";
}

.glyphicon-user:before {
  content: "\e008";
}

.glyphicon-film:before {
  content: "\e009";
}

.glyphicon-th-large:before {
  content: "\e010";
}

.glyphicon-th:before {
  content: "\e011";
}

.glyphicon-th-list:before {
  content: "\e012";
}

.glyphicon-ok:before {
  content: "\e013";
}

.glyphicon-remove:before {
  content: "\e014";
}

.glyphicon-zoom-in:before {
  content: "\e015";
}

.glyphicon-zoom-out:before {
  content: "\e016";
}

.glyphicon-off:before {
  content: "\e017";
}

.glyphicon-signal:before {
  content: "\e018";
}

.glyphicon-cog:before {
  content: "\e019";
}

.glyphicon-trash:before {
  content: "\e020";
}

.glyphicon-home:before {
  content: "\e021";
}

.glyphicon-file:before {
  content: "\e022";
}

.glyphicon-time:before {
  content: "\e023";
}

.glyphicon-road:before {
  content: "\e024";
}

.glyphicon-download-alt:before {
  content: "\e025";
}

.glyphicon-download:before {
  content: "\e026";
}

.glyphicon-upload:before {
  content: "\e027";
}

.glyphicon-inbox:before {
  content: "\e028";
}

.glyphicon-play-circle:before {
  content: "\e029";
}

.glyphicon-repeat:before {
  content: "\e030";
}

.glyphicon-refresh:before {
  content: "\e031";
}

.glyphicon-list-alt:before {
  content: "\e032";
}

.glyphicon-lock:before {
  content: "\e033";
}

.glyphicon-flag:before {
  content: "\e034";
}

.glyphicon-headphones:before {
  content: "\e035";
}

.glyphicon-volume-off:before {
  content: "\e036";
}

.glyphicon-volume-down:before {
  content: "\e037";
}

.glyphicon-volume-up:before {
  content: "\e038";
}

.glyphicon-qrcode:before {
  content: "\e039";
}

.glyphicon-barcode:before {
  content: "\e040";
}

.glyphicon-tag:before {
  content: "\e041";
}

.glyphicon-tags:before {
  content: "\e042";
}

.glyphicon-book:before {
  content: "\e043";
}

.glyphicon-bookmark:before {
  content: "\e044";
}

.glyphicon-print:before {
  content: "\e045";
}

.glyphicon-camera:before {
  content: "\e046";
}

.glyphicon-font:before {
  content: "\e047";
}

.glyphicon-bold:before {
  content: "\e048";
}

.glyphicon-italic:before {
  content: "\e049";
}

.glyphicon-text-height:before {
  content: "\e050";
}

.glyphicon-text-width:before {
  content: "\e051";
}

.glyphicon-align-left:before {
  content: "\e052";
}

.glyphicon-align-center:before {
  content: "\e053";
}

.glyphicon-align-right:before {
  content: "\e054";
}

.glyphicon-align-justify:before {
  content: "\e055";
}

.glyphicon-list:before {
  content: "\e056";
}

.glyphicon-indent-left:before {
  content: "\e057";
}

.glyphicon-indent-right:before {
  content: "\e058";
}

.glyphicon-facetime-video:before {
  content: "\e059";
}

.glyphicon-picture:before {
  content: "\e060";
}

.glyphicon-map-marker:before {
  content: "\e062";
}

.glyphicon-adjust:before {
  content: "\e063";
}

.glyphicon-tint:before {
  content: "\e064";
}

.glyphicon-edit:before {
  content: "\e065";
}

.glyphicon-share:before {
  content: "\e066";
}

.glyphicon-check:before {
  content: "\e067";
}

.glyphicon-move:before {
  content: "\e068";
}

.glyphicon-step-backward:before {
  content: "\e069";
}

.glyphicon-fast-backward:before {
  content: "\e070";
}

.glyphicon-backward:before {
  content: "\e071";
}

.glyphicon-play:before {
  content: "\e072";
}

.glyphicon-pause:before {
  content: "\e073";
}

.glyphicon-stop:before {
  content: "\e074";
}

.glyphicon-forward:before {
  content: "\e075";
}

.glyphicon-fast-forward:before {
  content: "\e076";
}

.glyphicon-step-forward:before {
  content: "\e077";
}

.glyphicon-eject:before {
  content: "\e078";
}

.glyphicon-chevron-left:before {
  content: "\e079";
}

.glyphicon-chevron-right:before {
  content: "\e080";
}

.glyphicon-plus-sign:before {
  content: "\e081";
}

.glyphicon-minus-sign:before {
  content: "\e082";
}

.glyphicon-remove-sign:before {
  content: "\e083";
}

.glyphicon-ok-sign:before {
  content: "\e084";
}

.glyphicon-question-sign:before {
  content: "\e085";
}

.glyphicon-info-sign:before {
  content: "\e086";
}

.glyphicon-screenshot:before {
  content: "\e087";
}

.glyphicon-remove-circle:before {
  content: "\e088";
}

.glyphicon-ok-circle:before {
  content: "\e089";
}

.glyphicon-ban-circle:before {
  content: "\e090";
}

.glyphicon-arrow-left:before {
  content: "\e091";
}

.glyphicon-arrow-right:before {
  content: "\e092";
}

.glyphicon-arrow-up:before {
  content: "\e093";
}

.glyphicon-arrow-down:before {
  content: "\e094";
}

.glyphicon-share-alt:before {
  content: "\e095";
}

.glyphicon-resize-full:before {
  content: "\e096";
}

.glyphicon-resize-small:before {
  content: "\e097";
}

.glyphicon-exclamation-sign:before {
  content: "\e101";
}

.glyphicon-gift:before {
  content: "\e102";
}

.glyphicon-leaf:before {
  content: "\e103";
}

.glyphicon-fire:before {
  content: "\e104";
}

.glyphicon-eye-open:before {
  content: "\e105";
}

.glyphicon-eye-close:before {
  content: "\e106";
}

.glyphicon-warning-sign:before {
  content: "\e107";
}

.glyphicon-plane:before {
  content: "\e108";
}

.glyphicon-calendar:before {
  content: "\e109";
}

.glyphicon-random:before {
  content: "\e110";
}

.glyphicon-comment:before {
  content: "\e111";
}

.glyphicon-magnet:before {
  content: "\e112";
}

.glyphicon-chevron-up:before {
  content: "\e113";
}

.glyphicon-chevron-down:before {
  content: "\e114";
}

.glyphicon-retweet:before {
  content: "\e115";
}

.glyphicon-shopping-cart:before {
  content: "\e116";
}

.glyphicon-folder-close:before {
  content: "\e117";
}

.glyphicon-folder-open:before {
  content: "\e118";
}

.glyphicon-resize-vertical:before {
  content: "\e119";
}

.glyphicon-resize-horizontal:before {
  content: "\e120";
}

.glyphicon-hdd:before {
  content: "\e121";
}

.glyphicon-bullhorn:before {
  content: "\e122";
}

.glyphicon-bell:before {
  content: "\e123";
}

.glyphicon-certificate:before {
  content: "\e124";
}

.glyphicon-thumbs-up:before {
  content: "\e125";
}

.glyphicon-thumbs-down:before {
  content: "\e126";
}

.glyphicon-hand-right:before {
  content: "\e127";
}

.glyphicon-hand-left:before {
  content: "\e128";
}

.glyphicon-hand-up:before {
  content: "\e129";
}

.glyphicon-hand-down:before {
  content: "\e130";
}

.glyphicon-circle-arrow-right:before {
  content: "\e131";
}

.glyphicon-circle-arrow-left:before {
  content: "\e132";
}

.glyphicon-circle-arrow-up:before {
  content: "\e133";
}

.glyphicon-circle-arrow-down:before {
  content: "\e134";
}

.glyphicon-globe:before {
  content: "\e135";
}

.glyphicon-wrench:before {
  content: "\e136";
}

.glyphicon-tasks:before {
  content: "\e137";
}

.glyphicon-filter:before {
  content: "\e138";
}

.glyphicon-briefcase:before {
  content: "\e139";
}

.glyphicon-fullscreen:before {
  content: "\e140";
}

.glyphicon-dashboard:before {
  content: "\e141";
}

.glyphicon-paperclip:before {
  content: "\e142";
}

.glyphicon-heart-empty:before {
  content: "\e143";
}

.glyphicon-link:before {
  content: "\e144";
}

.glyphicon-phone:before {
  content: "\e145";
}

.glyphicon-pushpin:before {
  content: "\e146";
}

.glyphicon-usd:before {
  content: "\e148";
}

.glyphicon-gbp:before {
  content: "\e149";
}

.glyphicon-sort:before {
  content: "\e150";
}

.glyphicon-sort-by-alphabet:before {
  content: "\e151";
}

.glyphicon-sort-by-alphabet-alt:before {
  content: "\e152";
}

.glyphicon-sort-by-order:before {
  content: "\e153";
}

.glyphicon-sort-by-order-alt:before {
  content: "\e154";
}

.glyphicon-sort-by-attributes:before {
  content: "\e155";
}

.glyphicon-sort-by-attributes-alt:before {
  content: "\e156";
}

.glyphicon-unchecked:before {
  content: "\e157";
}

.glyphicon-expand:before {
  content: "\e158";
}

.glyphicon-collapse-down:before {
  content: "\e159";
}

.glyphicon-collapse-up:before {
  content: "\e160";
}

.glyphicon-log-in:before {
  content: "\e161";
}

.glyphicon-flash:before {
  content: "\e162";
}

.glyphicon-log-out:before {
  content: "\e163";
}

.glyphicon-new-window:before {
  content: "\e164";
}

.glyphicon-record:before {
  content: "\e165";
}

.glyphicon-save:before {
  content: "\e166";
}

.glyphicon-open:before {
  content: "\e167";
}

.glyphicon-saved:before {
  content: "\e168";
}

.glyphicon-import:before {
  content: "\e169";
}

.glyphicon-export:before {
  content: "\e170";
}

.glyphicon-send:before {
  content: "\e171";
}

.glyphicon-floppy-disk:before {
  content: "\e172";
}

.glyphicon-floppy-saved:before {
  content: "\e173";
}

.glyphicon-floppy-remove:before {
  content: "\e174";
}

.glyphicon-floppy-save:before {
  content: "\e175";
}

.glyphicon-floppy-open:before {
  content: "\e176";
}

.glyphicon-credit-card:before {
  content: "\e177";
}

.glyphicon-transfer:before {
  content: "\e178";
}

.glyphicon-cutlery:before {
  content: "\e179";
}

.glyphicon-header:before {
  content: "\e180";
}

.glyphicon-compressed:before {
  content: "\e181";
}

.glyphicon-earphone:before {
  content: "\e182";
}

.glyphicon-phone-alt:before {
  content: "\e183";
}

.glyphicon-tower:before {
  content: "\e184";
}

.glyphicon-stats:before {
  content: "\e185";
}

.glyphicon-sd-video:before {
  content: "\e186";
}

.glyphicon-hd-video:before {
  content: "\e187";
}

.glyphicon-subtitles:before {
  content: "\e188";
}

.glyphicon-sound-stereo:before {
  content: "\e189";
}

.glyphicon-sound-dolby:before {
  content: "\e190";
}

.glyphicon-sound-5-1:before {
  content: "\e191";
}

.glyphicon-sound-6-1:before {
  content: "\e192";
}

.glyphicon-sound-7-1:before {
  content: "\e193";
}

.glyphicon-copyright-mark:before {
  content: "\e194";
}

.glyphicon-registration-mark:before {
  content: "\e195";
}

.glyphicon-cloud-download:before {
  content: "\e197";
}

.glyphicon-cloud-upload:before {
  content: "\e198";
}

.glyphicon-tree-conifer:before {
  content: "\e199";
}

.glyphicon-tree-deciduous:before {
  content: "\e200";
}

.glyphicon-cd:before {
  content: "\e201";
}

.glyphicon-save-file:before {
  content: "\e202";
}

.glyphicon-open-file:before {
  content: "\e203";
}

.glyphicon-level-up:before {
  content: "\e204";
}

.glyphicon-copy:before {
  content: "\e205";
}

.glyphicon-paste:before {
  content: "\e206";
}

.glyphicon-alert:before {
  content: "\e209";
}

.glyphicon-equalizer:before {
  content: "\e210";
}

.glyphicon-king:before {
  content: "\e211";
}

.glyphicon-queen:before {
  content: "\e212";
}

.glyphicon-pawn:before {
  content: "\e213";
}

.glyphicon-bishop:before {
  content: "\e214";
}

.glyphicon-knight:before {
  content: "\e215";
}

.glyphicon-baby-formula:before {
  content: "\e216";
}

.glyphicon-tent:before {
  content: "\26fa";
}

.glyphicon-blackboard:before {
  content: "\e218";
}

.glyphicon-bed:before {
  content: "\e219";
}

.glyphicon-apple:before {
  content: "\f8ff";
}

.glyphicon-erase:before {
  content: "\e221";
}

.glyphicon-hourglass:before {
  content: "\231b";
}

.glyphicon-lamp:before {
  content: "\e223";
}

.glyphicon-duplicate:before {
  content: "\e224";
}

.glyphicon-piggy-bank:before {
  content: "\e225";
}

.glyphicon-scissors:before {
  content: "\e226";
}

.glyphicon-bitcoin:before {
  content: "\e227";
}

.glyphicon-btc:before {
  content: "\e227";
}

.glyphicon-xbt:before {
  content: "\e227";
}

.glyphicon-yen:before {
  content: "\00a5";
}

.glyphicon-jpy:before {
  content: "\00a5";
}

.glyphicon-ruble:before {
  content: "\20bd";
}

.glyphicon-rub:before {
  content: "\20bd";
}

.glyphicon-scale:before {
  content: "\e230";
}

.glyphicon-ice-lolly:before {
  content: "\e231";
}

.glyphicon-ice-lolly-tasted:before {
  content: "\e232";
}

.glyphicon-education:before {
  content: "\e233";
}

.glyphicon-option-horizontal:before {
  content: "\e234";
}

.glyphicon-option-vertical:before {
  content: "\e235";
}

.glyphicon-menu-hamburger:before {
  content: "\e236";
}

.glyphicon-modal-window:before {
  content: "\e237";
}

.glyphicon-oil:before {
  content: "\e238";
}

.glyphicon-grain:before {
  content: "\e239";
}

.glyphicon-sunglasses:before {
  content: "\e240";
}

.glyphicon-text-size:before {
  content: "\e241";
}

.glyphicon-text-color:before {
  content: "\e242";
}

.glyphicon-text-background:before {
  content: "\e243";
}

.glyphicon-object-align-top:before {
  content: "\e244";
}

.glyphicon-object-align-bottom:before {
  content: "\e245";
}

.glyphicon-object-align-horizontal:before {
  content: "\e246";
}

.glyphicon-object-align-left:before {
  content: "\e247";
}

.glyphicon-object-align-vertical:before {
  content: "\e248";
}

.glyphicon-object-align-right:before {
  content: "\e249";
}

.glyphicon-triangle-right:before {
  content: "\e250";
}

.glyphicon-triangle-left:before {
  content: "\e251";
}

.glyphicon-triangle-bottom:before {
  content: "\e252";
}

.glyphicon-triangle-top:before {
  content: "\e253";
}

.glyphicon-console:before {
  content: "\e254";
}

.glyphicon-superscript:before {
  content: "\e255";
}

.glyphicon-subscript:before {
  content: "\e256";
}

.glyphicon-menu-left:before {
  content: "\e257";
}

.glyphicon-menu-right:before {
  content: "\e258";
}

.glyphicon-menu-down:before {
  content: "\e259";
}

.glyphicon-menu-up:before {
  content: "\e260";
}

<a href="#"><span class="glyphicon glyphicon-question-sign"></span></a>