Главная страница » CSS » 8. Каскадность

8. Каскадность

Каскадность — это принцип, на основе которого CSS применяет стили к элементам на веб-странице. Этот принцип позволяет определять, какие стили применяются к элементам, когда несколько стилей могут конфликтовать. Понимание каскадности важно для создания и поддержания гибких и легко управляемых стилей.

Основы каскадности

Каскадность в CSS основана на трёх основных принципах:

Специфичность: Определяет, какие стили применяются к элементам, когда несколько правил могут применяться к одному и тому же элементу.
Источник: Определяет, откуда применяются стили (встроенные стили, внешние таблицы стилей, пользовательские стили и т.д.).
Порядок в коде: Если два правила имеют одинаковую специфичность, применяется то правило, которое идёт позже в коде.

Специфичность

Специфичность — это мера важности стиля. CSS использует специфичность для определения, какое правило применить, когда несколько правил могут быть применены к одному элементу. Специфичность рассчитывается по следующим правилам:

Inline стили (встроенные стили) имеют наивысшую специфичность. Они имеют специфичность 1000.

				
					<p style="color: red;">Этот текст будет красным.</p>

ID-селекторы имеют специфичность 100.

				
					#header {
    color: blue;
}

Классы, атрибуты и псевдоклассы имеют специфичность 10.

				
					.highlight {
    background-color: yellow;
}
[type="text"] {
    border: 1px solid #ccc;
}
a:hover {
    color: green;
}

Теговые селекторы и псевдоэлементы имеют специфичность 1.

				
					p {
    color: black;
}
::first-line {
    font-weight: bold;
}

Общие селекторы имеют специфичность 0.

				
					* {
    margin: 0;
}

Пример специфичности:

				
					<!DOCTYPE html>
<html>
<head>
    <style>
        p {
            color: black; /* Специфичность: 1 */
        }
        .highlight {
            color: blue; /* Специфичность: 10 */
        }
        #main {
            color: green; /* Специфичность: 100 */
        }
        p.highlight {
            color: red; /* Специфичность: 11 */
        }
        p#main {
            color: orange; /* Специфичность: 101 */
        }
        p.highlight#main {
            color: purple; /* Специфичность: 111 */
        }
    </style>
</head>
<body>
    <p id="main" class="highlight">Этот текст будет пурпурным.</p>
<script>"use strict";function wprRemoveCPCSS(){var preload_stylesheets=document.querySelectorAll('link[data-rocket-async="style"][rel="preload"]');if(preload_stylesheets&&0<preload_stylesheets.length)for(var stylesheet_index=0;stylesheet_index<preload_stylesheets.length;stylesheet_index++){var media=preload_stylesheets[stylesheet_index].getAttribute("media")||"all";if(window.matchMedia(media).matches)return void setTimeout(wprRemoveCPCSS,200)}var elem=document.getElementById("rocket-critical-css");elem&&"remove"in elem&&elem.remove()}window.addEventListener?window.addEventListener("load",wprRemoveCPCSS):window.attachEvent&&window.attachEvent("onload",wprRemoveCPCSS);</script><script>class RocketElementorAnimation{constructor(){this.deviceMode=document.createElement("span"),this.deviceMode.id="elementor-device-mode-wpr",this.deviceMode.setAttribute("class","elementor-screen-only"),document.body.appendChild(this.deviceMode)}_detectAnimations(){let t=getComputedStyle(this.deviceMode,":after").content.replace(/"/g,"");this.animationSettingKeys=this._listAnimationSettingsKeys(t),document.querySelectorAll(".elementor-invisible[data-settings]").forEach(t=>{const e=t.getBoundingClientRect();if(e.bottom>=0&&e.top<=window.innerHeight)try{this._animateElement(t)}catch(t){}})}_animateElement(t){const e=JSON.parse(t.dataset.settings),i=e._animation_delay||e.animation_delay||0,n=e[this.animationSettingKeys.find(t=>e[t])];if("none"===n)return void t.classList.remove("elementor-invisible");t.classList.remove(n),this.currentAnimation&&t.classList.remove(this.currentAnimation),this.currentAnimation=n;let s=setTimeout(()=>{t.classList.remove("elementor-invisible"),t.classList.add("animated",n),this._removeAnimationSettings(t,e)},i);window.addEventListener("rocket-startLoading",function(){clearTimeout(s)})}_listAnimationSettingsKeys(t="mobile"){const e=[""];switch(t){case"mobile":e.unshift("_mobile");case"tablet":e.unshift("_tablet");case"desktop":e.unshift("_desktop")}const i=[];return["animation","_animation"].forEach(t=>{e.forEach(e=>{i.push(t+e)})}),i}_removeAnimationSettings(t,e){this._listAnimationSettingsKeys().forEach(t=>delete e[t]),t.dataset.settings=JSON.stringify(e)}static run(){const t=new RocketElementorAnimation;requestAnimationFrame(t._detectAnimations.bind(t))}}document.addEventListener("DOMContentLoaded",RocketElementorAnimation.run);</script><noscript><link rel='stylesheet' id='hello-elementor-theme-style-css' href='https://codefor.tech/wp-content/themes/hello-elementor/theme.min.css?ver=3.0.2' media='all' /><link data-minify="1" rel='stylesheet' id='jet-menu-hello-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/jet-menu/integration/themes/hello-elementor/assets/css/style.css?ver=1724486282' media='all' /><link rel='stylesheet' id='sweetalert2-css' href='https://codefor.tech/wp-content/plugins/user-registration/assets/css/sweetalert2/sweetalert2.min.css?ver=10.16.7' media='all' /><link data-minify="1" rel='stylesheet' id='user-registration-general-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/user-registration/assets/css/user-registration.css?ver=1724486282' media='all' /><link data-minify="1" rel='stylesheet' id='user-registration-smallscreen-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/user-registration/assets/css/user-registration-smallscreen.css?ver=1724486282' media='only screen and (max-width: 768px)' /><link data-minify="1" rel='stylesheet' id='user-registration-my-account-layout-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/user-registration/assets/css/my-account-layout.css?ver=1724486282' media='all' /><link data-minify="1" rel='stylesheet' id='dashicons-css' href='https://codefor.tech/wp-content/cache/min/1/wp-includes/css/dashicons.min.css?ver=1724486282' media='all' /><link rel='stylesheet' id='hello-elementor-css' href='https://codefor.tech/wp-content/themes/hello-elementor/style.min.css?ver=3.0.2' media='all' /><link rel='stylesheet' id='hello-elementor-header-footer-css' href='https://codefor.tech/wp-content/themes/hello-elementor/header-footer.min.css?ver=3.0.2' media='all' /><link rel='stylesheet' id='elementor-frontend-css' href='https://codefor.tech/wp-content/plugins/elementor/assets/css/frontend-lite.min.css?ver=3.21.8' media='all' /><link rel='stylesheet' id='elementor-post-6-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-6.css?ver=1718118435' media='all' /><link data-minify="1" rel='stylesheet' id='font-awesome-all-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/jet-menu/assets/public/lib/font-awesome/css/all.min.css?ver=1724486282' media='all' /><link rel='stylesheet' id='font-awesome-v4-shims-css' href='https://codefor.tech/wp-content/plugins/jet-menu/assets/public/lib/font-awesome/css/v4-shims.min.css?ver=5.12.0' media='all' /><link data-minify="1" rel='stylesheet' id='jet-menu-public-styles-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/jet-menu/assets/public/css/public.css?ver=1724486282' media='all' /><link data-minify="1" rel='stylesheet' id='swiper-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/elementor/assets/lib/swiper/v8/css/swiper.min.css?ver=1724486282' media='all' /><link rel='stylesheet' id='elementor-pro-css' href='https://codefor.tech/wp-content/plugins/elementor-pro/assets/css/frontend-lite.min.css?ver=3.21.3' media='all' /><link rel='stylesheet' id='elementor-global-css' href='https://codefor.tech/wp-content/uploads/elementor/css/global.css?ver=1718118436' media='all' /><link rel='stylesheet' id='elementor-post-1832-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-1832.css?ver=1722991509' media='all' /><link rel='stylesheet' id='elementor-post-8-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-8.css?ver=1719760051' media='all' /><link rel='stylesheet' id='elementor-post-42-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-42.css?ver=1718469014' media='all' /><link rel='stylesheet' id='jquery-chosen-css' href='https://codefor.tech/wp-content/plugins/jet-search/assets/lib/chosen/chosen.min.css?ver=1.8.7' media='all' /><link data-minify="1" rel='stylesheet' id='jet-search-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/jet-search/assets/css/jet-search.css?ver=1724486282' media='all' /><link rel='stylesheet' id='google-fonts-1-css' href='https://fonts.googleapis.com/css?family=Roboto%3A100%2C100italic%2C200%2C200italic%2C300%2C300italic%2C400%2C400italic%2C500%2C500italic%2C600%2C600italic%2C700%2C700italic%2C800%2C800italic%2C900%2C900italic%7CRoboto+Slab%3A100%2C100italic%2C200%2C200italic%2C300%2C300italic%2C400%2C400italic%2C500%2C500italic%2C600%2C600italic%2C700%2C700italic%2C800%2C800italic%2C900%2C900italic&#038;display=swap&#038;subset=cyrillic&#038;ver=6.6.2' media='all' /><link rel="stylesheet" href="https://codefor.tech/wp-content/plugins/elementor-pro/assets/css/widget-theme-elements.min.css"><link rel="stylesheet" href="styles.css"><link rel="stylesheet" href="styles.css"><link rel="stylesheet" href="https://codefor.tech/wp-content/plugins/elementor/assets/css/widget-icon-list.min.css"><link rel='stylesheet' id='elementor-post-416-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-416.css?ver=1724268811' media='all' /><link rel='stylesheet' id='elementor-post-471-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-471.css?ver=1722847712' media='all' /><link rel='stylesheet' id='prismjs_style-css' href='https://codefor.tech/wp-content/plugins/elementor-pro/assets/css/modules/code-highlight.min.css?ver=1.23.0' media='' /><link data-minify="1" rel='stylesheet' id='mailpoet_public-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/mailpoet/assets/dist/css/mailpoet-public.c7ad0042.css?ver=1724486282' media='all' /><link rel='stylesheet' id='mailpoet_custom_fonts_0-css' href='https://fonts.googleapis.com/css?family=Abril+FatFace%3A400%2C400i%2C700%2C700i%7CAlegreya%3A400%2C400i%2C700%2C700i%7CAlegreya+Sans%3A400%2C400i%2C700%2C700i%7CAmatic+SC%3A400%2C400i%2C700%2C700i%7CAnonymous+Pro%3A400%2C400i%2C700%2C700i%7CArchitects+Daughter%3A400%2C400i%2C700%2C700i%7CArchivo%3A400%2C400i%2C700%2C700i%7CArchivo+Narrow%3A400%2C400i%2C700%2C700i%7CAsap%3A400%2C400i%2C700%2C700i%7CBarlow%3A400%2C400i%2C700%2C700i%7CBioRhyme%3A400%2C400i%2C700%2C700i%7CBonbon%3A400%2C400i%2C700%2C700i%7CCabin%3A400%2C400i%2C700%2C700i%7CCairo%3A400%2C400i%2C700%2C700i%7CCardo%3A400%2C400i%2C700%2C700i%7CChivo%3A400%2C400i%2C700%2C700i%7CConcert+One%3A400%2C400i%2C700%2C700i%7CCormorant%3A400%2C400i%2C700%2C700i%7CCrimson+Text%3A400%2C400i%2C700%2C700i%7CEczar%3A400%2C400i%2C700%2C700i%7CExo+2%3A400%2C400i%2C700%2C700i%7CFira+Sans%3A400%2C400i%2C700%2C700i%7CFjalla+One%3A400%2C400i%2C700%2C700i%7CFrank+Ruhl+Libre%3A400%2C400i%2C700%2C700i%7CGreat+Vibes%3A400%2C400i%2C700%2C700i&#038;ver=6.6.2' media='all' /><link rel='stylesheet' id='mailpoet_custom_fonts_1-css' href='https://fonts.googleapis.com/css?family=Heebo%3A400%2C400i%2C700%2C700i%7CIBM+Plex%3A400%2C400i%2C700%2C700i%7CInconsolata%3A400%2C400i%2C700%2C700i%7CIndie+Flower%3A400%2C400i%2C700%2C700i%7CInknut+Antiqua%3A400%2C400i%2C700%2C700i%7CInter%3A400%2C400i%2C700%2C700i%7CKarla%3A400%2C400i%2C700%2C700i%7CLibre+Baskerville%3A400%2C400i%2C700%2C700i%7CLibre+Franklin%3A400%2C400i%2C700%2C700i%7CMontserrat%3A400%2C400i%2C700%2C700i%7CNeuton%3A400%2C400i%2C700%2C700i%7CNotable%3A400%2C400i%2C700%2C700i%7CNothing+You+Could+Do%3A400%2C400i%2C700%2C700i%7CNoto+Sans%3A400%2C400i%2C700%2C700i%7CNunito%3A400%2C400i%2C700%2C700i%7COld+Standard+TT%3A400%2C400i%2C700%2C700i%7COxygen%3A400%2C400i%2C700%2C700i%7CPacifico%3A400%2C400i%2C700%2C700i%7CPoppins%3A400%2C400i%2C700%2C700i%7CProza+Libre%3A400%2C400i%2C700%2C700i%7CPT+Sans%3A400%2C400i%2C700%2C700i%7CPT+Serif%3A400%2C400i%2C700%2C700i%7CRakkas%3A400%2C400i%2C700%2C700i%7CReenie+Beanie%3A400%2C400i%2C700%2C700i%7CRoboto+Slab%3A400%2C400i%2C700%2C700i&#038;ver=6.6.2' media='all' /><link rel='stylesheet' id='mailpoet_custom_fonts_2-css' href='https://fonts.googleapis.com/css?family=Ropa+Sans%3A400%2C400i%2C700%2C700i%7CRubik%3A400%2C400i%2C700%2C700i%7CShadows+Into+Light%3A400%2C400i%2C700%2C700i%7CSpace+Mono%3A400%2C400i%2C700%2C700i%7CSpectral%3A400%2C400i%2C700%2C700i%7CSue+Ellen+Francisco%3A400%2C400i%2C700%2C700i%7CTitillium+Web%3A400%2C400i%2C700%2C700i%7CUbuntu%3A400%2C400i%2C700%2C700i%7CVarela%3A400%2C400i%2C700%2C700i%7CVollkorn%3A400%2C400i%2C700%2C700i%7CWork+Sans%3A400%2C400i%2C700%2C700i%7CYatra+One%3A400%2C400i%2C700%2C700i&#038;ver=6.6.2' media='all' /><link rel='stylesheet' id='elementor-post-487-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-487.css?ver=1719159596' media='all' /><link rel='stylesheet' id='elementor-post-497-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-497.css?ver=1724485504' media='all' /><link rel='stylesheet' id='elementor-post-503-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-503.css?ver=1718466482' media='all' /><link rel='stylesheet' id='elementor-post-329-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-329.css?ver=1718467092' media='all' /></noscript></body>
</html>

В этом примере <p id="main" class="highlight"> будет иметь пурпурный цвет, так как правило с максимальной специфичностью p.highlight#main перекрывает остальные правила.

Источники стилей

CSS стили могут быть заданы в разных местах:

Встроенные стили (inline styles): Стили, заданные непосредственно в HTML-элементе с помощью атрибута style.

				
					<p style="color: red;">Этот текст будет красным.</p>

Внутренние таблицы стилей (internal styles): Стили, заданные внутри тега <style> в HTML-документе.

				
					<style>
    p {
        color: blue;
    }
</style>

Внешние таблицы стилей (external styles): Стили, заданные в отдельных CSS-файлах, подключаемых с помощью тега <link>.

				
					<link rel="preload" href="styles.css" data-rocket-async="style" as="style" onload="this.onload=null;this.rel='stylesheet'" onerror="this.removeAttribute('data-rocket-async')" >

Порядок в коде

Когда два правила имеют одинаковую специфичность, применяется правило, которое идет позже в коде. Это называется принципом «последнего выигрыша».

Пример:

				
					<!DOCTYPE html>
<html>
<head>
    <style>
        p {
            color: black; /* Применится, если нет других правил */
        }
        p {
            color: blue; /* Применится, так как это правило идет позже */
        }
    </style>
</head>
<body>
    <p>Этот текст будет синим.</p>
<noscript><link rel='stylesheet' id='hello-elementor-theme-style-css' href='https://codefor.tech/wp-content/themes/hello-elementor/theme.min.css?ver=3.0.2' media='all' /><link data-minify="1" rel='stylesheet' id='jet-menu-hello-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/jet-menu/integration/themes/hello-elementor/assets/css/style.css?ver=1724486282' media='all' /><link rel='stylesheet' id='sweetalert2-css' href='https://codefor.tech/wp-content/plugins/user-registration/assets/css/sweetalert2/sweetalert2.min.css?ver=10.16.7' media='all' /><link data-minify="1" rel='stylesheet' id='user-registration-general-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/user-registration/assets/css/user-registration.css?ver=1724486282' media='all' /><link data-minify="1" rel='stylesheet' id='user-registration-smallscreen-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/user-registration/assets/css/user-registration-smallscreen.css?ver=1724486282' media='only screen and (max-width: 768px)' /><link data-minify="1" rel='stylesheet' id='user-registration-my-account-layout-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/user-registration/assets/css/my-account-layout.css?ver=1724486282' media='all' /><link data-minify="1" rel='stylesheet' id='dashicons-css' href='https://codefor.tech/wp-content/cache/min/1/wp-includes/css/dashicons.min.css?ver=1724486282' media='all' /><link rel='stylesheet' id='hello-elementor-css' href='https://codefor.tech/wp-content/themes/hello-elementor/style.min.css?ver=3.0.2' media='all' /><link rel='stylesheet' id='hello-elementor-header-footer-css' href='https://codefor.tech/wp-content/themes/hello-elementor/header-footer.min.css?ver=3.0.2' media='all' /><link rel='stylesheet' id='elementor-frontend-css' href='https://codefor.tech/wp-content/plugins/elementor/assets/css/frontend-lite.min.css?ver=3.21.8' media='all' /><link rel='stylesheet' id='elementor-post-6-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-6.css?ver=1718118435' media='all' /><link data-minify="1" rel='stylesheet' id='font-awesome-all-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/jet-menu/assets/public/lib/font-awesome/css/all.min.css?ver=1724486282' media='all' /><link rel='stylesheet' id='font-awesome-v4-shims-css' href='https://codefor.tech/wp-content/plugins/jet-menu/assets/public/lib/font-awesome/css/v4-shims.min.css?ver=5.12.0' media='all' /><link data-minify="1" rel='stylesheet' id='jet-menu-public-styles-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/jet-menu/assets/public/css/public.css?ver=1724486282' media='all' /><link data-minify="1" rel='stylesheet' id='swiper-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/elementor/assets/lib/swiper/v8/css/swiper.min.css?ver=1724486282' media='all' /><link rel='stylesheet' id='elementor-pro-css' href='https://codefor.tech/wp-content/plugins/elementor-pro/assets/css/frontend-lite.min.css?ver=3.21.3' media='all' /><link rel='stylesheet' id='elementor-global-css' href='https://codefor.tech/wp-content/uploads/elementor/css/global.css?ver=1718118436' media='all' /><link rel='stylesheet' id='elementor-post-1832-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-1832.css?ver=1722991509' media='all' /><link rel='stylesheet' id='elementor-post-8-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-8.css?ver=1719760051' media='all' /><link rel='stylesheet' id='elementor-post-42-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-42.css?ver=1718469014' media='all' /><link rel='stylesheet' id='jquery-chosen-css' href='https://codefor.tech/wp-content/plugins/jet-search/assets/lib/chosen/chosen.min.css?ver=1.8.7' media='all' /><link data-minify="1" rel='stylesheet' id='jet-search-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/jet-search/assets/css/jet-search.css?ver=1724486282' media='all' /><link rel='stylesheet' id='google-fonts-1-css' href='https://fonts.googleapis.com/css?family=Roboto%3A100%2C100italic%2C200%2C200italic%2C300%2C300italic%2C400%2C400italic%2C500%2C500italic%2C600%2C600italic%2C700%2C700italic%2C800%2C800italic%2C900%2C900italic%7CRoboto+Slab%3A100%2C100italic%2C200%2C200italic%2C300%2C300italic%2C400%2C400italic%2C500%2C500italic%2C600%2C600italic%2C700%2C700italic%2C800%2C800italic%2C900%2C900italic&#038;display=swap&#038;subset=cyrillic&#038;ver=6.6.2' media='all' /><link rel="stylesheet" href="https://codefor.tech/wp-content/plugins/elementor-pro/assets/css/widget-theme-elements.min.css"><link rel="stylesheet" href="styles.css"><link rel="stylesheet" href="styles.css"><link rel="stylesheet" href="https://codefor.tech/wp-content/plugins/elementor/assets/css/widget-icon-list.min.css"><link rel='stylesheet' id='elementor-post-416-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-416.css?ver=1724268811' media='all' /><link rel='stylesheet' id='elementor-post-471-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-471.css?ver=1722847712' media='all' /><link rel='stylesheet' id='prismjs_style-css' href='https://codefor.tech/wp-content/plugins/elementor-pro/assets/css/modules/code-highlight.min.css?ver=1.23.0' media='' /><link data-minify="1" rel='stylesheet' id='mailpoet_public-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/mailpoet/assets/dist/css/mailpoet-public.c7ad0042.css?ver=1724486282' media='all' /><link rel='stylesheet' id='mailpoet_custom_fonts_0-css' href='https://fonts.googleapis.com/css?family=Abril+FatFace%3A400%2C400i%2C700%2C700i%7CAlegreya%3A400%2C400i%2C700%2C700i%7CAlegreya+Sans%3A400%2C400i%2C700%2C700i%7CAmatic+SC%3A400%2C400i%2C700%2C700i%7CAnonymous+Pro%3A400%2C400i%2C700%2C700i%7CArchitects+Daughter%3A400%2C400i%2C700%2C700i%7CArchivo%3A400%2C400i%2C700%2C700i%7CArchivo+Narrow%3A400%2C400i%2C700%2C700i%7CAsap%3A400%2C400i%2C700%2C700i%7CBarlow%3A400%2C400i%2C700%2C700i%7CBioRhyme%3A400%2C400i%2C700%2C700i%7CBonbon%3A400%2C400i%2C700%2C700i%7CCabin%3A400%2C400i%2C700%2C700i%7CCairo%3A400%2C400i%2C700%2C700i%7CCardo%3A400%2C400i%2C700%2C700i%7CChivo%3A400%2C400i%2C700%2C700i%7CConcert+One%3A400%2C400i%2C700%2C700i%7CCormorant%3A400%2C400i%2C700%2C700i%7CCrimson+Text%3A400%2C400i%2C700%2C700i%7CEczar%3A400%2C400i%2C700%2C700i%7CExo+2%3A400%2C400i%2C700%2C700i%7CFira+Sans%3A400%2C400i%2C700%2C700i%7CFjalla+One%3A400%2C400i%2C700%2C700i%7CFrank+Ruhl+Libre%3A400%2C400i%2C700%2C700i%7CGreat+Vibes%3A400%2C400i%2C700%2C700i&#038;ver=6.6.2' media='all' /><link rel='stylesheet' id='mailpoet_custom_fonts_1-css' href='https://fonts.googleapis.com/css?family=Heebo%3A400%2C400i%2C700%2C700i%7CIBM+Plex%3A400%2C400i%2C700%2C700i%7CInconsolata%3A400%2C400i%2C700%2C700i%7CIndie+Flower%3A400%2C400i%2C700%2C700i%7CInknut+Antiqua%3A400%2C400i%2C700%2C700i%7CInter%3A400%2C400i%2C700%2C700i%7CKarla%3A400%2C400i%2C700%2C700i%7CLibre+Baskerville%3A400%2C400i%2C700%2C700i%7CLibre+Franklin%3A400%2C400i%2C700%2C700i%7CMontserrat%3A400%2C400i%2C700%2C700i%7CNeuton%3A400%2C400i%2C700%2C700i%7CNotable%3A400%2C400i%2C700%2C700i%7CNothing+You+Could+Do%3A400%2C400i%2C700%2C700i%7CNoto+Sans%3A400%2C400i%2C700%2C700i%7CNunito%3A400%2C400i%2C700%2C700i%7COld+Standard+TT%3A400%2C400i%2C700%2C700i%7COxygen%3A400%2C400i%2C700%2C700i%7CPacifico%3A400%2C400i%2C700%2C700i%7CPoppins%3A400%2C400i%2C700%2C700i%7CProza+Libre%3A400%2C400i%2C700%2C700i%7CPT+Sans%3A400%2C400i%2C700%2C700i%7CPT+Serif%3A400%2C400i%2C700%2C700i%7CRakkas%3A400%2C400i%2C700%2C700i%7CReenie+Beanie%3A400%2C400i%2C700%2C700i%7CRoboto+Slab%3A400%2C400i%2C700%2C700i&#038;ver=6.6.2' media='all' /><link rel='stylesheet' id='mailpoet_custom_fonts_2-css' href='https://fonts.googleapis.com/css?family=Ropa+Sans%3A400%2C400i%2C700%2C700i%7CRubik%3A400%2C400i%2C700%2C700i%7CShadows+Into+Light%3A400%2C400i%2C700%2C700i%7CSpace+Mono%3A400%2C400i%2C700%2C700i%7CSpectral%3A400%2C400i%2C700%2C700i%7CSue+Ellen+Francisco%3A400%2C400i%2C700%2C700i%7CTitillium+Web%3A400%2C400i%2C700%2C700i%7CUbuntu%3A400%2C400i%2C700%2C700i%7CVarela%3A400%2C400i%2C700%2C700i%7CVollkorn%3A400%2C400i%2C700%2C700i%7CWork+Sans%3A400%2C400i%2C700%2C700i%7CYatra+One%3A400%2C400i%2C700%2C700i&#038;ver=6.6.2' media='all' /><link rel='stylesheet' id='elementor-post-487-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-487.css?ver=1719159596' media='all' /><link rel='stylesheet' id='elementor-post-497-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-497.css?ver=1724485504' media='all' /><link rel='stylesheet' id='elementor-post-503-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-503.css?ver=1718466482' media='all' /><link rel='stylesheet' id='elementor-post-329-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-329.css?ver=1718467092' media='all' /></noscript></body>
</html>

В этом примере текст <p> будет синим, поскольку второе правило перекрывает первое из-за порядка следования.

Распространённые ошибки

Неудобочитаемый CSS-код: Отсутствие структуры и порядка в CSS может привести к путанице и ошибкам. Используйте комментарии и группируйте стили для улучшения читаемости.
Перекрытие стилей: При определении стилей для одного элемента важно учитывать специфичность и порядок в коде, чтобы избежать неожиданных результатов.
Чрезмерное использование !important: Использование !important для принудительного применения стилей может сделать код трудно поддерживаемым и усложнить его обновление.

Заключение

Каскадность в CSS помогает управлять конфликтами стилей и определять, какие стили применяются к элементам. Понимание принципов специфичности, источников стилей и порядка в коде поможет вам создавать более организованный и поддерживаемый CSS-код.

Тестовое задание

Создайте HTML-документ с элементами <p>, <div>, <h1>, <a> и <input>.
Определите стили для этих элементов в разных источниках (встроенные стили, внутренние и внешние таблицы стилей).
Примените различные уровни специфичности и порядок в коде, чтобы увидеть, как это влияет на отображение элементов.

HTML-документ:

				
					<!DOCTYPE html>
<html>
<head>
    <style>
        p {
            color: black; /* Специфичность: 1 */
        }
        .highlight {
            color: blue; /* Специфичность: 10 */
        }
        #main {
            color: green; /* Специфичность: 100 */
        }
        p.highlight {
            color: red; /* Специфичность: 11 */
        }
        p#main {
            color: orange; /* Специфичность: 101 */
        }
        p.highlight#main {
            color: purple; /* Специфичность: 111 */
        }
    </style>
    <link rel="preload" href="styles.css" data-rocket-async="style" as="style" onload="this.onload=null;this.rel='stylesheet'" onerror="this.removeAttribute('data-rocket-async')" >
</head>
<body>
    <h1>Main Heading</h1>
    <div>
        <p id="main" class="highlight">This text should appear purple.</p>
        <p class="highlight">This text should appear red.</p>
    </div>
    <a href="#">A link</a>
    <input type="text" placeholder="Type here">
    <style>
        h1 {
            color: pink; /* Применится из-за порядка */
        }
    </style>
<noscript><link rel='stylesheet' id='hello-elementor-theme-style-css' href='https://codefor.tech/wp-content/themes/hello-elementor/theme.min.css?ver=3.0.2' media='all' /><link data-minify="1" rel='stylesheet' id='jet-menu-hello-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/jet-menu/integration/themes/hello-elementor/assets/css/style.css?ver=1724486282' media='all' /><link rel='stylesheet' id='sweetalert2-css' href='https://codefor.tech/wp-content/plugins/user-registration/assets/css/sweetalert2/sweetalert2.min.css?ver=10.16.7' media='all' /><link data-minify="1" rel='stylesheet' id='user-registration-general-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/user-registration/assets/css/user-registration.css?ver=1724486282' media='all' /><link data-minify="1" rel='stylesheet' id='user-registration-smallscreen-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/user-registration/assets/css/user-registration-smallscreen.css?ver=1724486282' media='only screen and (max-width: 768px)' /><link data-minify="1" rel='stylesheet' id='user-registration-my-account-layout-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/user-registration/assets/css/my-account-layout.css?ver=1724486282' media='all' /><link data-minify="1" rel='stylesheet' id='dashicons-css' href='https://codefor.tech/wp-content/cache/min/1/wp-includes/css/dashicons.min.css?ver=1724486282' media='all' /><link rel='stylesheet' id='hello-elementor-css' href='https://codefor.tech/wp-content/themes/hello-elementor/style.min.css?ver=3.0.2' media='all' /><link rel='stylesheet' id='hello-elementor-header-footer-css' href='https://codefor.tech/wp-content/themes/hello-elementor/header-footer.min.css?ver=3.0.2' media='all' /><link rel='stylesheet' id='elementor-frontend-css' href='https://codefor.tech/wp-content/plugins/elementor/assets/css/frontend-lite.min.css?ver=3.21.8' media='all' /><link rel='stylesheet' id='elementor-post-6-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-6.css?ver=1718118435' media='all' /><link data-minify="1" rel='stylesheet' id='font-awesome-all-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/jet-menu/assets/public/lib/font-awesome/css/all.min.css?ver=1724486282' media='all' /><link rel='stylesheet' id='font-awesome-v4-shims-css' href='https://codefor.tech/wp-content/plugins/jet-menu/assets/public/lib/font-awesome/css/v4-shims.min.css?ver=5.12.0' media='all' /><link data-minify="1" rel='stylesheet' id='jet-menu-public-styles-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/jet-menu/assets/public/css/public.css?ver=1724486282' media='all' /><link data-minify="1" rel='stylesheet' id='swiper-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/elementor/assets/lib/swiper/v8/css/swiper.min.css?ver=1724486282' media='all' /><link rel='stylesheet' id='elementor-pro-css' href='https://codefor.tech/wp-content/plugins/elementor-pro/assets/css/frontend-lite.min.css?ver=3.21.3' media='all' /><link rel='stylesheet' id='elementor-global-css' href='https://codefor.tech/wp-content/uploads/elementor/css/global.css?ver=1718118436' media='all' /><link rel='stylesheet' id='elementor-post-1832-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-1832.css?ver=1722991509' media='all' /><link rel='stylesheet' id='elementor-post-8-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-8.css?ver=1719760051' media='all' /><link rel='stylesheet' id='elementor-post-42-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-42.css?ver=1718469014' media='all' /><link rel='stylesheet' id='jquery-chosen-css' href='https://codefor.tech/wp-content/plugins/jet-search/assets/lib/chosen/chosen.min.css?ver=1.8.7' media='all' /><link data-minify="1" rel='stylesheet' id='jet-search-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/jet-search/assets/css/jet-search.css?ver=1724486282' media='all' /><link rel='stylesheet' id='google-fonts-1-css' href='https://fonts.googleapis.com/css?family=Roboto%3A100%2C100italic%2C200%2C200italic%2C300%2C300italic%2C400%2C400italic%2C500%2C500italic%2C600%2C600italic%2C700%2C700italic%2C800%2C800italic%2C900%2C900italic%7CRoboto+Slab%3A100%2C100italic%2C200%2C200italic%2C300%2C300italic%2C400%2C400italic%2C500%2C500italic%2C600%2C600italic%2C700%2C700italic%2C800%2C800italic%2C900%2C900italic&#038;display=swap&#038;subset=cyrillic&#038;ver=6.6.2' media='all' /><link rel="stylesheet" href="https://codefor.tech/wp-content/plugins/elementor-pro/assets/css/widget-theme-elements.min.css"><link rel="stylesheet" href="styles.css"><link rel="stylesheet" href="styles.css"><link rel="stylesheet" href="https://codefor.tech/wp-content/plugins/elementor/assets/css/widget-icon-list.min.css"><link rel='stylesheet' id='elementor-post-416-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-416.css?ver=1724268811' media='all' /><link rel='stylesheet' id='elementor-post-471-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-471.css?ver=1722847712' media='all' /><link rel='stylesheet' id='prismjs_style-css' href='https://codefor.tech/wp-content/plugins/elementor-pro/assets/css/modules/code-highlight.min.css?ver=1.23.0' media='' /><link data-minify="1" rel='stylesheet' id='mailpoet_public-css' href='https://codefor.tech/wp-content/cache/min/1/wp-content/plugins/mailpoet/assets/dist/css/mailpoet-public.c7ad0042.css?ver=1724486282' media='all' /><link rel='stylesheet' id='mailpoet_custom_fonts_0-css' href='https://fonts.googleapis.com/css?family=Abril+FatFace%3A400%2C400i%2C700%2C700i%7CAlegreya%3A400%2C400i%2C700%2C700i%7CAlegreya+Sans%3A400%2C400i%2C700%2C700i%7CAmatic+SC%3A400%2C400i%2C700%2C700i%7CAnonymous+Pro%3A400%2C400i%2C700%2C700i%7CArchitects+Daughter%3A400%2C400i%2C700%2C700i%7CArchivo%3A400%2C400i%2C700%2C700i%7CArchivo+Narrow%3A400%2C400i%2C700%2C700i%7CAsap%3A400%2C400i%2C700%2C700i%7CBarlow%3A400%2C400i%2C700%2C700i%7CBioRhyme%3A400%2C400i%2C700%2C700i%7CBonbon%3A400%2C400i%2C700%2C700i%7CCabin%3A400%2C400i%2C700%2C700i%7CCairo%3A400%2C400i%2C700%2C700i%7CCardo%3A400%2C400i%2C700%2C700i%7CChivo%3A400%2C400i%2C700%2C700i%7CConcert+One%3A400%2C400i%2C700%2C700i%7CCormorant%3A400%2C400i%2C700%2C700i%7CCrimson+Text%3A400%2C400i%2C700%2C700i%7CEczar%3A400%2C400i%2C700%2C700i%7CExo+2%3A400%2C400i%2C700%2C700i%7CFira+Sans%3A400%2C400i%2C700%2C700i%7CFjalla+One%3A400%2C400i%2C700%2C700i%7CFrank+Ruhl+Libre%3A400%2C400i%2C700%2C700i%7CGreat+Vibes%3A400%2C400i%2C700%2C700i&#038;ver=6.6.2' media='all' /><link rel='stylesheet' id='mailpoet_custom_fonts_1-css' href='https://fonts.googleapis.com/css?family=Heebo%3A400%2C400i%2C700%2C700i%7CIBM+Plex%3A400%2C400i%2C700%2C700i%7CInconsolata%3A400%2C400i%2C700%2C700i%7CIndie+Flower%3A400%2C400i%2C700%2C700i%7CInknut+Antiqua%3A400%2C400i%2C700%2C700i%7CInter%3A400%2C400i%2C700%2C700i%7CKarla%3A400%2C400i%2C700%2C700i%7CLibre+Baskerville%3A400%2C400i%2C700%2C700i%7CLibre+Franklin%3A400%2C400i%2C700%2C700i%7CMontserrat%3A400%2C400i%2C700%2C700i%7CNeuton%3A400%2C400i%2C700%2C700i%7CNotable%3A400%2C400i%2C700%2C700i%7CNothing+You+Could+Do%3A400%2C400i%2C700%2C700i%7CNoto+Sans%3A400%2C400i%2C700%2C700i%7CNunito%3A400%2C400i%2C700%2C700i%7COld+Standard+TT%3A400%2C400i%2C700%2C700i%7COxygen%3A400%2C400i%2C700%2C700i%7CPacifico%3A400%2C400i%2C700%2C700i%7CPoppins%3A400%2C400i%2C700%2C700i%7CProza+Libre%3A400%2C400i%2C700%2C700i%7CPT+Sans%3A400%2C400i%2C700%2C700i%7CPT+Serif%3A400%2C400i%2C700%2C700i%7CRakkas%3A400%2C400i%2C700%2C700i%7CReenie+Beanie%3A400%2C400i%2C700%2C700i%7CRoboto+Slab%3A400%2C400i%2C700%2C700i&#038;ver=6.6.2' media='all' /><link rel='stylesheet' id='mailpoet_custom_fonts_2-css' href='https://fonts.googleapis.com/css?family=Ropa+Sans%3A400%2C400i%2C700%2C700i%7CRubik%3A400%2C400i%2C700%2C700i%7CShadows+Into+Light%3A400%2C400i%2C700%2C700i%7CSpace+Mono%3A400%2C400i%2C700%2C700i%7CSpectral%3A400%2C400i%2C700%2C700i%7CSue+Ellen+Francisco%3A400%2C400i%2C700%2C700i%7CTitillium+Web%3A400%2C400i%2C700%2C700i%7CUbuntu%3A400%2C400i%2C700%2C700i%7CVarela%3A400%2C400i%2C700%2C700i%7CVollkorn%3A400%2C400i%2C700%2C700i%7CWork+Sans%3A400%2C400i%2C700%2C700i%7CYatra+One%3A400%2C400i%2C700%2C700i&#038;ver=6.6.2' media='all' /><link rel='stylesheet' id='elementor-post-487-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-487.css?ver=1719159596' media='all' /><link rel='stylesheet' id='elementor-post-497-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-497.css?ver=1724485504' media='all' /><link rel='stylesheet' id='elementor-post-503-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-503.css?ver=1718466482' media='all' /><link rel='stylesheet' id='elementor-post-329-css' href='https://codefor.tech/wp-content/uploads/elementor/css/post-329.css?ver=1718467092' media='all' /></noscript></body>
</html>

Выполнив это задание, вы получите понимание принципов каскадности и научитесь применять их на практике для создания гибких и управляемых стилей.

Регистрация

Вход

Поиск