为什么我的 HTML/CSS 网站顶部有空白？ [复制]答案

【问题标题】：Why is there white space at the top of my HTML/CSS website? [duplicate]为什么我的 HTML/CSS 网站顶部有空白？ [复制]
【发布时间】：2019-06-01 05:17:21
【问题描述】：

我的 HTML/CSS 项目顶部有一个我无法摆脱的奇怪空白。我如何摆脱空白？即使不使用normalize.css 文件也可以看到它，尽管我在normalize.css 中将边距和填充设置为0，所以这不是问题。我制作了一个 JSsn-p here，可能更容易理解。

* {
        margin: 0;
        padding: 0;
        border: 0;
        outline: 0;
        font-size: 100%;
        vertical-align: baseline;
        background: transparent;
        box-sizing: border-box;
    }

这是我的项目的 HTML/CSS 代码：

HTML：

<!DOCTYPE html>
<html>
    <head>
        <title>SuperMegaAwesome Landing Page | Matt Bell</title>
        <link rel="stylesheet" type="text/css" href="./Stylesheets/CSS/main.css">
        <link rel="stylesheet" type="text/css" href="./Stylesheets/CSS/normalize.css">
    </head>

    <body>
        <header>
            <p id="logo">Super<span>Mega</span>Awesome</p>

            <nav>
                <a href="#">Home</a>
                <a href="#">Portfolio</a>
                <a href="#">Services</a>
                <a href="#">Get in touch</a>
            </nav>
        </header>

        <section id="hero">
            <div id="hero_overlay">
                <div class="wrapper">
                    <div id="content">
                        <h1 class="title">We create beautiful products</h1>
                        <h2 class="sub_title">Truffaut DIY keffiyeh, twee messenger bag venmo locavore organic master cleanse marfa gochujang selvage</h2>
                        <div class="button_wrapper">
                            <a href="#" class="button button_highlight">Learn More</a>
                            <a href="#" class="button button_secondary">Play Video</a>
                        </div>
                    </div>
                </div>
            </div>
        </section>
        <div>hELLO</div>
        <div>HELLOOO</div>
        <footer>Hello</footer>
    </body>
</html>

CSS：

body {
  font-family: "Brandon Grotesque", Helvetica, sans-serif;
}

.wrapper {
  width: 90vw;
  height: 100%;
  margin: 0 auto;
  background-color: rgba(100, 100, 0, 0.4);
}

header {
  position: fixed;
  height: 10vh;
  width: 100vw;
}
header #logo {
  color: #FFFFFF;
  font-weight: 700;
  font-size: 1.35rem;
  position: absolute;
  left: 10vw;
  top: 50%;
  transform: translateY(-50%);
}
header #logo span {
  font-weight: 300;
}
header nav {
  position: absolute;
  right: 10vw;
  top: 50%;
  transform: translateY(-50%);
}
header nav a {
  color: #FFFFFF;
  font-weight: 700;
  text-decoration: none;
  margin-left: 3vw;
}

#hero {
  background-image: url(../../images/banner_background.jpg);
  background-repeat: no-repeat;
  background-size: cover;
  background-position: top;
  height: 95vh;
}
#hero #hero_overlay {
  background-color: rgba(0, 0, 0, 0.4);
  width: 100%;
  height: 100%;
}
#hero .title, #hero .sub_title {
  color: #FFFFFF;
  text-align: center;
}
#hero .title {
  font-size: 3.5rem;
}

/*# sourceMappingURL=main.css.map */

我还使用 normalize.css 进行了一些调整，以使跨浏览器的格式化成为同义词：

* {
        margin: 0;
        padding: 0;
        border: 0;
        outline: 0;
        font-size: 100%;
        vertical-align: baseline;
        background: transparent;
        box-sizing: border-box;
    }

/*! normalize.css v8.0.1 | MIT License | github.com/necolas/normalize.css */

/* Document
   ========================================================================== */

/**
 * 1. Correct the line height in all browsers.
 * 2. Prevent adjustments of font size after orientation changes in iOS.
 */

html {
  line-height: 1.15; /* 1 */
  -webkit-text-size-adjust: 100%; /* 2 */
  padding: 0;
  margin: 0;
}

/* Sections
   ========================================================================== */

/**
 * Remove the margin in all browsers.
 */

body {
  margin: 0;
  padding: 0;
}

/**
 * Render the `main` element consistently in IE.
 */

main {
  display: block;
}

/**
 * Correct the font size and margin on `h1` elements within `section` and
 * `article` contexts in Chrome, Firefox, and Safari.
 */

h1 {
  font-size: 2em;
  margin: 0.67em 0;
}

/* Grouping content
   ========================================================================== */

/**
 * 1. Add the correct box sizing in Firefox.
 * 2. Show the overflow in Edge and IE.
 */

hr {
  height: 0; /* 1 */
  overflow: visible; /* 2 */
}

/**
 * 1. Correct the inheritance and scaling of font size in all browsers.
 * 2. Correct the odd `em` font sizing in all browsers.
 */

pre {
  font-family: monospace, monospace; /* 1 */
  font-size: 1em; /* 2 */
}

/* Text-level semantics
   ========================================================================== */

/**
 * Remove the gray background on active links in IE 10.
 */

a {
  background-color: transparent;
}

/**
 * 1. Remove the bottom border in Chrome 57-
 * 2. Add the correct text decoration in Chrome, Edge, IE, Opera, and Safari.
 */

abbr[title] {
  border-bottom: none; /* 1 */
  text-decoration: underline; /* 2 */
  text-decoration: underline dotted; /* 2 */
}

/**
 * Add the correct font weight in Chrome, Edge, and Safari.
 */

b,
strong {
  font-weight: bolder;
}

/**
 * 1. Correct the inheritance and scaling of font size in all browsers.
 * 2. Correct the odd `em` font sizing in all browsers.
 */

code,
kbd,
samp {
  font-family: monospace, monospace; /* 1 */
  font-size: 1em; /* 2 */
}

/**
 * Add the correct font size in all browsers.
 */

small {
  font-size: 80%;
}

/**
 * Prevent `sub` and `sup` elements from affecting the line height in
 * all browsers.
 */

sub,
sup {
  font-size: 75%;
  line-height: 0;
  position: relative;
  vertical-align: baseline;
}

sub {
  bottom: -0.25em;
}

sup {
  top: -0.5em;
}

/* Embedded content
   ========================================================================== */

/**
 * Remove the border on images inside links in IE 10.
 */

img {
  border-style: none;
}

/* Forms
   ========================================================================== */

/**
 * 1. Change the font styles in all browsers.
 * 2. Remove the margin in Firefox and Safari.
 */

button,
input,
optgroup,
select,
textarea {
  font-family: inherit; /* 1 */
  font-size: 100%; /* 1 */
  line-height: 1.15; /* 1 */
  margin: 0; /* 2 */
}

/**
 * Show the overflow in IE.
 * 1. Show the overflow in Edge.
 */

button,
input { /* 1 */
  overflow: visible;
}

/**
 * Remove the inheritance of text transform in Edge, Firefox, and IE.
 * 1. Remove the inheritance of text transform in Firefox.
 */

button,
select { /* 1 */
  text-transform: none;
}

/**
 * Correct the inability to style clickable types in iOS and Safari.
 */

button,
[type="button"],
[type="reset"],
[type="submit"] {
  -webkit-appearance: button;
}

/**
 * Remove the inner border and padding in Firefox.
 */

button::-moz-focus-inner,
[type="button"]::-moz-focus-inner,
[type="reset"]::-moz-focus-inner,
[type="submit"]::-moz-focus-inner {
  border-style: none;
  padding: 0;
}

/**
 * Restore the focus styles unset by the previous rule.
 */

button:-moz-focusring,
[type="button"]:-moz-focusring,
[type="reset"]:-moz-focusring,
[type="submit"]:-moz-focusring {
  outline: 1px dotted ButtonText;
}

/**
 * Correct the padding in Firefox.
 */

fieldset {
  padding: 0.35em 0.75em 0.625em;
}

/**
 * 1. Correct the text wrapping in Edge and IE.
 * 2. Correct the color inheritance from `fieldset` elements in IE.
 * 3. Remove the padding so developers are not caught out when they zero out
 *    `fieldset` elements in all browsers.
 */

legend {
  box-sizing: border-box; /* 1 */
  color: inherit; /* 2 */
  display: table; /* 1 */
  max-width: 100%; /* 1 */
  padding: 0; /* 3 */
  white-space: normal; /* 1 */
}

/**
 * Add the correct vertical alignment in Chrome, Firefox, and Opera.
 */

progress {
  vertical-align: baseline;
}

/**
 * Remove the default vertical scrollbar in IE 10+.
 */

textarea {
  overflow: auto;
}

/**
 * 1. Add the correct box sizing in IE 10.
 * 2. Remove the padding in IE 10.
 */

[type="checkbox"],
[type="radio"] {
  box-sizing: border-box; /* 1 */
  padding: 0; /* 2 */
}

/**
 * Correct the cursor style of increment and decrement buttons in Chrome.
 */

[type="number"]::-webkit-inner-spin-button,
[type="number"]::-webkit-outer-spin-button {
  height: auto;
}

/**
 * 1. Correct the odd appearance in Chrome and Safari.
 * 2. Correct the outline style in Safari.
 */

[type="search"] {
  -webkit-appearance: textfield; /* 1 */
  outline-offset: -2px; /* 2 */
}

/**
 * Remove the inner padding in Chrome and Safari on macOS.
 */

[type="search"]::-webkit-search-decoration {
  -webkit-appearance: none;
}

/**
 * 1. Correct the inability to style clickable types in iOS and Safari.
 * 2. Change font properties to `inherit` in Safari.
 */

::-webkit-file-upload-button {
  -webkit-appearance: button; /* 1 */
  font: inherit; /* 2 */
}

/* Interactive
   ========================================================================== */

/*
 * Add the correct display in Edge, IE 10+, and Firefox.
 */

details {
  display: block;
}

/*
 * Add the correct display in all browsers.
 */

summary {
  display: list-item;
}

/* Misc
   ========================================================================== */

/**
 * Add the correct display in IE 10+.
 */

template {
  display: none;
}

/**
 * Add the correct display in IE 10.
 */

[hidden] {
  display: none;
}

【问题讨论】：

制作嵌入代码 sn-p 或者可能是 jsfiddle 或链接到实时站点，因为有时很难仅从您的代码中分辨出来
感谢@zack6849 的提示。我做了一个 jsfiddle here

标签： html css

【解决方案1】：

尝试添加这个：

body {
    margin: 0;
}
#hero .title {
    margin-top: 0;
}

所以body 和.title 的样式如下：

body {
    font-family: "Brandon Grotesque", Helvetica, sans-serif;
    margin: 0;
}
#hero .title {
    margin-top: 0;
    font-size: 3.5rem;
}

【讨论】：

成功了，谢谢！但我不完全理解它为什么会起作用，我以为我已经用* {margin: 0;} 将所有边距设置为 0@
我只是指出了空格。现在您可以根据需要进行设置。 :)
@Patho63 够公平

【解决方案2】：

这是由margin collapsing 现象引起的。见related question。如果您删除 main.css 的内容，您会看到布局变得“正常”（例如顶部没有空白），因此 normalize.css 不是导致问题。

如何解决？

只需将其添加到您的 normalize.css *{} 部分。见fiddle。

* {
overflow:hidden; /* or auto */
}

【讨论】：