2nd/10_Wiki/Topic_CSS/CSS_Form_Focus.md

id, title, category, status, verification_status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, created_at, updated_at, review_reason, merge_history, tags, raw_sources, applied_in, github_commit

id	title	category	status	verification_status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	created_at	updated_at	review_reason	merge_history	tags	raw_sources	applied_in	github_commit
css-input-focus-and-icons	CSS Input Focus and Icons	Frontend	draft	conceptual		CSS form focus input focus styling focus pseudo-class search input icon animated search input		B	0.88	2026-06-23	2026-06-23			css web frontend w3schools forms focus pseudo-class	https://www.w3schools.com/css/css_form_focus.asp

CSS Input Focus and Icons

🎯 한 줄 통찰 (One-line insight)

The :focus pseudo-class lets you restyle an input the moment it is clicked into, and combined with outline: none;, background-image, and transition, you can build clean focus states, icon-bearing fields, and animated search boxes. [S1]

🧠 핵심 개념 (Core concepts)

• Default focus outline — by default, some browsers add a blue outline around an input when it gets focus (is clicked on); outline: none; removes this behavior. [S1]
• :focus selector — used to do something with an input field when it gets focus. [S1]
• Input icons — an icon can be placed inside an input using background-image positioned via background-position, with a large left padding reserving space for the icon. [S1]
• Animated focus — the transition property can animate input changes (e.g., width) when the field gains focus. [S1]

🧩 추출된 패턴 (Extracted patterns)

• Reset-then-restyle on focus — remove the native outline, then express focus visually through your own property (background color, border). [S1]
• Icon = background-image + padding — render a decorative/functional icon by layering a non-repeating background image and reserving its space with padding-left. [S1]
• Focus-driven animation — declare transition on the base selector and the target value on the :focus selector so the change eases in. [S1]

📖 세부 내용 (Details)

Style Input with Focus By default, some browsers will add a blue outline around the input when it gets focus (clicked on). You can remove this behavior by adding outline: none; to the input. Use the :focus selector to do something with the input field when it gets focus. [S1]

Change the background color to lightblue on focus: [S1]

input[type=text]:focus {
  background-color: lightblue;
}

Add a border on focus: [S1]

input[type=text]:focus {
  border: 3px solid #555;
}

Style Input with Icon/Image If you want an icon inside the input, use the background-image property and position it with the background-position property. Also notice that we add a large left padding to reserve the space of the icon: [S1]

input[type=text] {
  background-color: white;
  background-image: url('searchicon.png');
  background-position: 10px 10px;
  background-repeat: no-repeat;
  padding-left: 40px;
}

Animated Search Input In this example we use the CSS transition property to animate the width of the search input when it gets focus. You will learn more about the transition property later, in the CSS Transitions chapter. [S1]

input[type=text] {
  transition: width 0.4s ease-in-out;
}

input[type=text]:focus {
  width: 100%;
}

🛠️ 적용 사례 (Applied in summary)

The page's own examples are the applied cases: a lightblue focus background, a 3px focus border, a search field with an embedded searchicon.png, and a search box that animates to full width on focus. No external project/commit applications found in the source.

💻 코드 패턴 (Code patterns)

Restyle on focus (language: CSS):

input[type=text]:focus {
  background-color: lightblue;
}

Icon inside input (language: CSS):

input[type=text] {
  background-image: url('searchicon.png');
  background-position: 10px 10px;
  background-repeat: no-repeat;
  padding-left: 40px;
}

⚖️ 모순 및 업데이트 (Contradictions & updates)

No contradictions found in the source.

✅ 검증 상태 및 신뢰도

• 상태: draft
• 검증 단계: conceptual (실제 적용 사례 발견 시 applied/validated로 승격 가능)
• 출처 신뢰도: B (W3Schools — widely used educational reference, not a primary standards body)
• 신뢰 점수: 0.88
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: CSS Tutorial
• 관련 개념: CSS Other Form Elements, CSS Forms, CSS Pseudo-classes, CSS Transitions
• 참조 맥락: Referenced when styling interactive form fields and search inputs for visible focus feedback.

📚 출처 (Sources)

• [S1] W3Schools — CSS Input Focus and Icons — https://www.w3schools.com/css/css_form_focus.asp

📝 변경 이력 (Change history)

• 2026-06-23: Initial draft synthesized from the W3Schools "CSS Input Focus and Icons" page (Astra wiki-curation, P-Reinforce v3.1 format).