/* ==========================================================================
   RESET
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  line-height: 1.5;
}

body {
  min-height: 100vh;
}

img,
picture,
video,
canvas,
svg {
  display: block;
  max-width: 100%;
}

input,
button,
textarea,
select {
  font: inherit;
}

a {
  color: inherit;
}

/* ==========================================================================
   THEME (CSS Variables)
   ========================================================================== */

:root {
  /* Light theme */
  --color-bg: #fafafa;
  --color-surface: #ffffff;
  --color-text: #1a1a1a;
  --color-text-muted: #666666;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-border: #e5e5e5;
  --color-tag-bg: #f0f0f0;
  --color-tag-text: #444444;
  --color-tag-active-bg: #2563eb;
  --color-tag-active-text: #ffffff;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0f0f0f;
    --color-surface: #1a1a1a;
    --color-text: #e5e5e5;
    --color-text-muted: #a0a0a0;
    --color-accent: #60a5fa;
    --color-accent-hover: #93c5fd;
    --color-border: #2a2a2a;
    --color-tag-bg: #2a2a2a;
    --color-tag-text: #c0c0c0;
    --color-tag-active-bg: #60a5fa;
    --color-tag-active-text: #0f0f0f;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
  }
}

/* ==========================================================================
   LAYOUT
   ========================================================================== */

body {
  background-color: var(--color-bg);
  color: var(--color-text);
  display: flex;
  flex-direction: column;
}

.container {
  width: 100%;
  max-width: 60rem;
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

main {
  flex: 1;
  padding-top: 3rem;
  padding-bottom: 4rem;
}

/* ==========================================================================
   TYPOGRAPHY
   ========================================================================== */

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
    Ubuntu, Cantarell, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
  font-size: 1rem;
  line-height: 1.7;
}

h1,
h2,
h3 {
  line-height: 1.3;
  font-weight: 600;
}

h1 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
}

h2 {
  font-size: 1.5rem;
  margin-top: 2rem;
  margin-bottom: 1rem;
}

h3 {
  font-size: 1.25rem;
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
}

p {
  margin-bottom: 1.25rem;
}

a {
  text-decoration: none;
  color: var(--color-accent);
  transition: color 0.15s ease;
}

a:hover {
  color: var(--color-accent-hover);
}

a:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* ==========================================================================
   COMPONENTS
   ========================================================================== */

/* --- Site Header --- */

.site-header {
  border-bottom: 1px solid var(--color-border);
  padding: 1rem 0;
}

.site-header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.site-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
}

.site-title:hover {
  color: var(--color-accent);
}

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

.site-nav a {
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

.site-nav a:hover {
  color: var(--color-accent);
}

/* --- Site Footer --- */

.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 2rem 0;
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.875rem;
}

/* --- Controls (Search, Clear) --- */

.controls {
  display: flex;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.search-input {
  flex: 1;
  min-width: 200px;
  padding: 0.625rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: 0.375rem;
  background-color: var(--color-surface);
  color: var(--color-text);
  font-size: 0.9rem;
}

.search-input::placeholder {
  color: var(--color-text-muted);
}

.search-input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.btn {
  padding: 0.625rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: 0.375rem;
  background-color: var(--color-surface);
  color: var(--color-text-muted);
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.btn:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* --- Tag Bar --- */

#tag-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 2rem;
}

.tag {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
  background-color: var(--color-tag-bg);
  color: var(--color-tag-text);
  font-size: 0.8rem;
  border: none;
  cursor: pointer;
  transition: all 0.15s ease;
}

.tag:hover {
  background-color: var(--color-accent);
  color: var(--color-tag-active-text);
}

.tag:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.tag.active {
  background-color: var(--color-tag-active-bg);
  color: var(--color-tag-active-text);
}

/* --- Post List --- */

#post-list {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.post-item {
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--color-border);
}

.post-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.post-item-date {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 0.25rem;
}

.post-item-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  line-height: 1.4;
}

.post-item-title a {
  color: var(--color-text);
}

.post-item-title a:hover {
  color: var(--color-accent);
}

.post-item-excerpt {
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
  font-size: 0.95rem;
}

.post-item-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.375rem;
}

.post-item-tags .tag {
  font-size: 0.75rem;
  padding: 0.125rem 0.5rem;
  cursor: default;
}

.post-item-tags .tag:hover {
  background-color: var(--color-tag-bg);
  color: var(--color-tag-text);
}

/* --- Single Post (Article Page) --- */

.post h1 {
  margin-bottom: 0.25rem;
}

.post-meta {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-bottom: 2rem;
}

.post-content {
  margin-top: 1.5rem;
}

.post-content p {
  margin-bottom: 1.25rem;
}

.post-content ul,
.post-content ol {
  margin-bottom: 1.25rem;
  padding-left: 1.5rem;
}

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

.post-content blockquote {
  border-left: 3px solid var(--color-accent);
  padding-left: 1rem;
  margin: 1.5rem 0;
  color: var(--color-text-muted);
  font-style: italic;
}

.post-content code {
  background-color: var(--color-tag-bg);
  padding: 0.125rem 0.375rem;
  border-radius: 0.25rem;
  font-size: 0.9em;
  font-family: "SF Mono", SFMono-Regular, Consolas, "Liberation Mono", Menlo,
    monospace;
}

.post-content pre {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 0.375rem;
  padding: 1rem;
  overflow-x: auto;
  margin-bottom: 1.5rem;
}

.post-content pre code {
  background: none;
  padding: 0;
}

.post-content table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
}

.post-content th,
.post-content td {
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--color-border);
  text-align: left;
}

.post-content th {
  background-color: var(--color-tag-bg);
  font-weight: 600;
}

.post-content hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 2rem 0;
}

.back-link {
  display: inline-block;
  margin-top: 3rem;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

.back-link:hover {
  color: var(--color-accent);
}

/* --- Message (Error/Info) --- */

.message {
  padding: 1.5rem;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 0.5rem;
  color: var(--color-text-muted);
  text-align: center;
}

/* --- About Page --- */

.about-content {
  max-width: 38rem;
}

.about-content p {
  margin-bottom: 1.25rem;
}

/* ==========================================================================
   UTILITIES
   ========================================================================== */

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