Inline Alert — StealThis.dev

コード

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f9fafb;
  color: #111;
  min-height: 100vh;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 40px 16px;
}

.demo {
  width: 100%;
  max-width: 560px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.section-label {
  font-size: 11px;
  font-weight: 700;
  color: #9ca3af;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 4px;
}

/* Alert base */
.alert {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 16px;
  border-radius: 12px;
  border-left: 4px solid transparent;
  animation: alert-in 0.2s ease;
}

@keyframes alert-in {
  from {
    opacity: 0;
    transform: translateY(-4px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.alert--info {
  background: #eff6ff;
  border-left-color: #6366f1;
}
.alert--success {
  background: #f0fdf4;
  border-left-color: #16a34a;
}
.alert--warning {
  background: #fffbeb;
  border-left-color: #d97706;
}
.alert--error {
  background: #fef2f2;
  border-left-color: #dc2626;
}
.alert--no-icon {
  border-left-color: #d97706;
}

.alert-icon {
  font-size: 16px;
  line-height: 1;
  flex-shrink: 0;
  margin-top: 2px;
}

.alert-content {
  flex: 1;
  min-width: 0;
}

.alert-title {
  font-size: 14px;
  font-weight: 700;
  color: #111827;
  margin-bottom: 3px;
}

.alert-desc {
  font-size: 13px;
  color: #374151;
  line-height: 1.5;
}

.alert-desc a {
  color: #6366f1;
  text-decoration: none;
  font-weight: 500;
}
.alert-desc a:hover {
  text-decoration: underline;
}

.alert-close {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 14px;
  color: #9ca3af;
  padding: 2px 4px;
  border-radius: 4px;
  line-height: 1;
  flex-shrink: 0;
  transition: color 0.15s, background 0.15s;
}
.alert-close:hover {
  color: #374151;
  background: rgba(0, 0, 0, 0.06);
}

/* Dismiss animation */
.alert.dismissing {
  animation: alert-out 0.25s ease forwards;
  overflow: hidden;
}

@keyframes alert-out {
  from {
    opacity: 1;
    max-height: 200px;
    margin-bottom: 0;
  }
  to {
    opacity: 0;
    max-height: 0;
    padding-top: 0;
    padding-bottom: 0;
    margin-bottom: -12px;
  }
}

document.querySelectorAll(".alert-close").forEach((btn) => {
  btn.addEventListener("click", () => {
    const alert = btn.closest(".alert");
    alert.classList.add("dismissing");
    alert.addEventListener("animationend", () => alert.remove(), { once: true });
  });
});

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>Inline Alert</title>
  <link rel="stylesheet" href="style.css" />
</head>
<body>
<div class="demo">
  <h2 class="section-label">Semantic variants</h2>

  <div class="alert alert--info" role="alert">
    <span class="alert-icon">ℹ️</span>
    <div class="alert-content">
      <p class="alert-title">New version available</p>
      <p class="alert-desc">Version 3.2.1 is available. <a href="#">View changelog</a> to see what's new.</p>
    </div>
    <button class="alert-close" aria-label="Dismiss">✕</button>
  </div>

  <div class="alert alert--success" role="alert">
    <span class="alert-icon">✅</span>
    <div class="alert-content">
      <p class="alert-title">Payment successful</p>
      <p class="alert-desc">Your subscription has been renewed. Receipt sent to [email protected].</p>
    </div>
    <button class="alert-close" aria-label="Dismiss">✕</button>
  </div>

  <div class="alert alert--warning" role="alert">
    <span class="alert-icon">⚠️</span>
    <div class="alert-content">
      <p class="alert-title">Storage almost full</p>
      <p class="alert-desc">You've used 90% of your storage. <a href="#">Upgrade your plan</a> to avoid interruption.</p>
    </div>
    <button class="alert-close" aria-label="Dismiss">✕</button>
  </div>

  <div class="alert alert--error" role="alert">
    <span class="alert-icon">🚨</span>
    <div class="alert-content">
      <p class="alert-title">Deployment failed</p>
      <p class="alert-desc">Build #142 failed with exit code 1. Check the <a href="#">build log</a> for details.</p>
    </div>
    <button class="alert-close" aria-label="Dismiss">✕</button>
  </div>

  <h2 class="section-label" style="margin-top:28px;">No title / simple</h2>

  <div class="alert alert--info" role="alert">
    <span class="alert-icon">ℹ️</span>
    <div class="alert-content">
      <p class="alert-desc">Your session will expire in 5 minutes.</p>
    </div>
  </div>

  <div class="alert alert--success" role="alert">
    <span class="alert-icon">✅</span>
    <div class="alert-content">
      <p class="alert-desc">All systems are operational.</p>
    </div>
  </div>

  <h2 class="section-label" style="margin-top:28px;">Inline (no icon)</h2>

  <div class="alert alert--warning alert--no-icon" role="alert">
    <div class="alert-content">
      <p class="alert-title">Review required</p>
      <p class="alert-desc">This action requires approval from an admin before it takes effect.</p>
    </div>
    <button class="alert-close" aria-label="Dismiss">✕</button>
  </div>
</div>
<script src="script.js"></script>
</body>
</html>

Inline alert component with four semantic variants (info, success, warning, error), icon, optional title, body text, and a dismissible close button. CSS-first with minimal JS for dismiss behavior.