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

img {
  max-width: 100%;
  display: block;
}

/* ---------- THEME VARIABLES ---------- */
:root {
  --color-bg: #0d1117;
  --color-text: #c9d1d9;
  --color-card: #161b22;
  --color-border: #30363d;
  --color-primary: #06acd3;
  --color-primary-hover: #0891b2;
  --radius: 0.5rem;
  --transition: all 0.2s ease;
}

body.light {
  --color-bg: #ffffff;
  --color-text: #24292f;
  --color-card: #f6f8fa;
  --color-border: #d0d7de;
}

/* ---------- GLOBAL ---------- */
body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  transition: var(--transition);
  line-height: 1.5;
}

/* Container system */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ---------- ACCESSIBILITY UTILITY ---------- */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* ---------- HEADER & NAV ---------- */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--color-border);
  padding: 1rem 0;
  margin-bottom: 2rem;
}

.logo {
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-desktop {
  display: flex;
  gap: 1.5rem;
}

.nav-desktop a,
.nav-mobile a {
  color: var(--color-text);
  text-decoration: none;
  transition: var(--transition);
}

.nav-desktop a:hover,
.nav-mobile a:hover {
  color: var(--color-primary);
}

.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  color: var(--color-text);
}

.theme-toggle svg {
  width: 1.5rem;
  height: 1.5rem;
}

.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--color-text);
}

.mobile-menu-toggle svg {
  width: 1.5rem;
  height: 1.5rem;
}

.nav-mobile {
  display: none;
  flex-direction: column;
  gap: 1rem;
  background: var(--color-card);
  border-radius: var(--radius);
  padding: 1rem;
  margin-bottom: 1.5rem;
  border: 1px solid var(--color-border);
}

.nav-mobile.active {
  display: flex;
}

/* ---------- FILTER BAR ---------- */
.filter-bar {
  display: flex;
  flex-wrap: nowrap;
  overflow-x: auto;
  gap: 0.5rem;
  padding-bottom: 1rem;
  margin-bottom: 2rem;
  scrollbar-width: thin;
}

.filter-bar::-webkit-scrollbar {
  height: 4px;
}

.filter-bar a {
  flex-shrink: 0;
  font-size: 0.875rem;
  font-weight: 500;
  padding: 0.5rem 1rem;
  border-radius: 9999px;
  background: rgba(99, 102, 241, 0.2);
  color: #818cf8;
  text-decoration: none;
  transition: var(--transition);
  white-space: nowrap;
}

.filter-bar a:hover {
  background: rgba(99, 102, 241, 0.3);
}

.filter-bar a.active {
  font-weight: bold;
  border-bottom: 2px solid var(--color-primary);
}

/* ---------- SEARCH ---------- */
.search-container {
  max-width: 500px;
  margin: 0 auto 2rem auto;
  position: relative;
}

.search-icon {
  position: absolute;
  top: 50%;
  left: 1rem;
  transform: translateY(-50%);
  opacity: 0.7;
}

.search-input {
  width: 100%;
  padding: 0.75rem 1rem 0.75rem 2.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  background: var(--color-card);
  color: var(--color-text);
  transition: var(--transition);
}

.search-input:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-color: transparent;
}

/* ---------- MAIN HEADING (H1) ---------- */
.main-heading {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--color-primary), #818cf8);
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
}

/* ---------- POSTS GRID ---------- */
.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
}

.posts-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 768px) {
  .posts-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .posts-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* Blog Card */
.blog-card {
  background: var(--color-card);
  padding: 1.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.blog-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.tag {
  font-size: 0.75rem;
  background: rgba(6, 172, 211, 0.2);
  color: var(--color-primary);
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
}

.card-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--color-text);
}

.card-date {
  font-size: 0.875rem;
  opacity: 0.7;
  margin-bottom: 1rem;
}

.card-summary {
  margin-bottom: 1rem;
  flex-grow: 1;
}

.card-link {
  color: var(--color-primary);
  font-weight: 600;
  text-decoration: none;
  align-self: flex-start;
}

.card-link:hover {
  text-decoration: underline;
}

/* ---------- BUTTONS ---------- */
.btn-primary {
  background: var(--color-primary);
  color: white;
  border: none;
  padding: 0.6rem 1.5rem;
  border-radius: 9999px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

.btn-primary:hover {
  background: var(--color-primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(6, 172, 219, 0.3);
}

button:focus-visible,
input:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.load-more-wrapper {
  display: flex;
  justify-content: center;
  margin-top: 2rem;
}

.loading {
  opacity: 0.6;
  pointer-events: none;
}

/* ---------- FOOTER ---------- */
.footer {
  margin-top: 4rem;
  text-align: center;
  border-top: 1px solid var(--color-border);
  padding-top: 2rem;
  font-size: 0.875rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-top: 1rem;
}

.footer-links a {
  color: var(--color-text);
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--color-primary);
}

/* ---------- RESPONSIVE ---------- */
@media (max-width: 768px) {
  .nav-desktop {
    display: none;
  }
  .mobile-menu-toggle {
    display: block;
  }
  .container {
    padding: 0 1rem;
  }
}

/* About Page */
.about-content {
  max-width: 800px;
  margin: 0 auto;
}

.about-card {
  background: var(--color-card);
  padding: 2rem;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
}

.about-card h2 {
  font-size: 1.75rem;
  margin-bottom: 1rem;
  color: var(--color-text);
}

.about-card p {
  margin-bottom: 1rem;
  line-height: 1.6;
}

/* Contact Page */
.contact-container {
  max-width: 700px;
  margin: 0 auto;
}

.contact-card {
  background: var(--color-card);
  padding: 2rem;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
}

.contact-intro {
  text-align: center;
  margin-bottom: 2rem;
  font-size: 1.1rem;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.form-group label {
  font-weight: 500;
}

.form-group input,
.form-group textarea {
  padding: 0.75rem;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  background: var(--color-bg);
  color: var(--color-text);
  font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-color: transparent;
}


/* ---------- BLOG POST PAGE ---------- */
.blog-post {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 0;
}

.tags {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.tag {
  font-size: 0.75rem;
  background: rgba(6, 172, 211, 0.2);
  color: var(--color-primary);
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
}

.post-meta {
  color: var(--color-text);
  opacity: 0.7;
  margin-bottom: 1.5rem;
  font-size: 0.875rem;
}

.featured-image {
  width: 100%;
  border-radius: var(--radius);
  margin: 1.5rem 0;
}

.post-content h2 {
  font-size: 1.5rem;
  margin: 1.5rem 0 1rem;
}

.post-content p {
  margin-bottom: 1rem;
  line-height: 1.7;
}

.post-content ul, .post-content ol {
  margin: 1rem 0 1rem 1.5rem;
}

.post-content li {
  margin-bottom: 0.5rem;
}

pre {
  background: var(--color-card);
  padding: 1rem;
  border-radius: var(--radius);
  overflow-x: auto;
  margin: 1.5rem 0;
  border: 1px solid var(--color-border);
}

code {
  font-family: 'Courier New', monospace;
  font-size: 0.9em;
}

.author-bio {
  display: flex;
  gap: 1rem;
  align-items: center;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--color-border);
}

.author-avatar {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  object-fit: cover;
}

.author-info p {
  margin-top: 0.25rem;
  font-size: 0.875rem;
  opacity: 0.8;
}