/* ===== CSS Variables ===== */
:root {
  /* Colors */
  --color-primary: #222;
  --color-dark: #000;
  --color-bg-main: #fdfcf8;
  --color-bg-alt: #f8f7f3;
  --color-text-light: #555;
  --color-text-lighter: #666;
  --color-text-lightest: #777;
  --color-border-light: #ddd;
  --color-border-medium: #ccc;
  --color-border-dark: #aaa;

  /* Fonts */
  --font-serif: "Georgia", "Times New Roman", serif;
  --font-sans: "Helvetica Neue", Helvetica, Arial, sans-serif;

  /* Transitions */
  --transition-default: all 0.2s ease;
  --transition-slow: all 0.3s ease;

  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;

  /* Sizes */
  --max-width: 960px;
}

/* ===== Base Layout ===== */
body {
  font-family: var(--font-sans);
  background-color: var(--color-bg-main);
  color: var(--color-primary);
  margin: 0;
  padding: 0;
  line-height: 1.6;
  font-size: 0.95rem;
  scroll-behavior: smooth;
}

/* ===== Header ===== */
header {
  text-align: center;
  padding: var(--spacing-lg) var(--spacing-sm) var(--spacing-xs);
  border-bottom: 3px solid var(--color-dark);
  background-color: var(--color-bg-main);
  position: relative;
  z-index: 2;
}

header h1 {
  margin: 0;
  font-family: var(--font-serif);
  font-size: 2.4rem;
  text-transform: uppercase;
  letter-spacing: 1px;
}

header h1 a {
  color: var(--color-primary);
  text-decoration: none;
  transition: var(--transition-default);
}

header h1 a:hover {
  color: var(--color-dark);
  opacity: 0.8;
}

header p {
  font-style: italic;
  color: var(--color-text-light);
  margin: 0.4rem 0 1.2rem;
  font-family: var(--font-serif);
}

/* ===== Sticky Navigation ===== */
nav {
  position: sticky;
  top: 0;
  z-index: 10;
  text-align: left;
  background: var(--color-bg-alt);
  border-top: 1px solid var(--color-border-medium);
  border-bottom: 1px solid var(--color-border-medium);
  padding: 0.6rem 0;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
  font-family: var(--font-serif);
}

nav a {
  color: var(--color-primary);
  text-decoration: none;
  margin: 0 0.8rem;
  font-weight: bold;
  font-size: 0.95rem;
  text-transform: uppercase;
  border-bottom: 2px solid transparent;
  transition: var(--transition-default);
}

nav a:hover {
  border-bottom-color: var(--color-dark);
}

/* ===== Floating Navigation ===== */
.floating-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  padding: var(--spacing-sm);
  pointer-events: none;
}

/* ===== Floating Menu Toggle Button ===== */
.floating-menu-toggle {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: 0.6rem var(--spacing-sm);
  background: var(--color-bg-alt);
  border: 2px solid var(--color-primary);
  border-radius: 4px;
  cursor: pointer;
  font-family: var(--font-serif);
  font-size: 0.9rem;
  color: var(--color-primary);
  transition: var(--transition-default);
  pointer-events: auto;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.floating-menu-toggle:hover,
.floating-menu-toggle.active {
  background: var(--color-primary);
  color: var(--color-bg-alt);
}

.floating-menu-toggle .toggle-icon {
  font-size: 0.7rem;
  transition: transform 0.3s ease;
}

.floating-menu-toggle.active .toggle-icon {
  transform: rotate(180deg);
}

/* ===== TOC List (Dropdown) ===== */
.floating-nav .toc-list {
  display: none;
  position: absolute;
  top: calc(100% + var(--spacing-xs));
  right: 0;
  min-width: 250px;
  max-width: 400px;
  max-height: 70vh;
  overflow-y: auto;
  background: var(--color-bg-alt);
  border: 2px solid var(--color-primary);
  border-radius: 4px;
  list-style: none;
  padding: var(--spacing-xs) 0;
  margin: 0;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  pointer-events: auto;
}

.floating-nav .toc-list.active {
  display: block;
}

.floating-nav .toc-list li {
  margin: 0;
  padding: 0;
}

.floating-nav .toc-list a {
  display: block;
  padding: 0.6rem var(--spacing-sm);
  color: var(--color-primary);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: normal;
  text-transform: none;
  border-bottom: 1px solid transparent;
  transition: var(--transition-default);
  font-family: var(--font-sans);
}

.floating-nav .toc-list a:hover {
  background: var(--color-primary);
  color: var(--color-bg-alt);
  border-bottom-color: transparent;
}

.floating-nav .toc-list li:last-child a {
  border-bottom: none;
}

/* ===== Main Content ===== */
main,
.post-content {
  max-width: var(--max-width);
  margin: var(--spacing-lg) auto;
  padding: 0 var(--spacing-md);
}

section {
  margin-bottom: 2.5rem;
  border-bottom: 1px dotted var(--color-border-dark);
  padding-bottom: 1.2rem;
}

section:last-of-type {
  border: none;
}

section h2 {
  border-left: 4px solid var(--color-dark);
  padding-left: 0.6rem;
  font-size: 1.5rem;
  margin-bottom: var(--spacing-xs);
  text-transform: uppercase;
  font-family: var(--font-serif);
}

section p {
  text-align: justify;
  margin: 0.4rem 0 0.8rem;
  font-family: var(--font-sans);
  font-size: 0.9rem;
}

/* ===== Articles ===== */
article {
  margin-bottom: 1.2rem;
  overflow: hidden;
}

article h3 {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  margin-bottom: 0.3rem;
}

article h3 a {
  color: var(--color-primary);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: var(--transition-default);
}

article h3 a:hover {
  color: var(--color-dark);
  border-bottom-color: var(--color-dark);
}

.post-meta {
  overflow: hidden;
  margin-bottom: var(--spacing-sm);
  font-size: 0.8rem;
  color: var(--color-text-lighter);
}

article p {
  margin-top: 0;
}

article .read-more {
  color: var(--color-text-lighter);
  text-decoration: none;
  font-size: 0.9em;
  font-style: italic;
  white-space: nowrap;
  border-bottom: 1px dotted var(--color-border-dark);
  transition: var(--transition-default);
}

article .read-more:hover {
  color: var(--color-dark);
  border-bottom-color: var(--color-dark);
}

.preview-container {
  display: block;
}

.preview-image {
  float: right;
  margin-left: var(--spacing-sm);
  margin-bottom: var(--spacing-xs);
  flex: 0 0 150px;
}

.preview-image img {
  width: 100%;
  height: auto;
  border-radius: 0;
  border: 1px solid var(--color-border-medium);
  max-height: 160px;
  filter: grayscale(100%);
}

.preview-text {
  flex: 1;
}

.preview-text p {
  text-align: justify;
}

/* ===== Link Lists ===== */
ul {
  list-style: none;
  padding-left: 0;
  margin: 0.2rem 0 0;
}

ul li {
  font-size: 0.85rem;
  margin-bottom: 0.3rem;
  line-height: 1.4;
}

ul li a {
  color: var(--color-primary);
  text-decoration: none;
  border-bottom: 1px solid var(--color-border-dark);
  transition: var(--transition-default);
  font-family: var(--font-serif);
}

ul li a:hover {
  color: var(--color-dark);
  border-bottom-color: var(--color-dark);
}

/* ===== Picture of the Day ===== */
.image-of-the-day {
  text-align: center;
  margin: var(--spacing-xl) 0;
  padding: var(--spacing-md) var(--spacing-sm);
  background-color: var(--color-bg-alt);
  border: 1px solid var(--color-border-light);
  box-shadow: 0 2px 6px rgba(0,0,0,0.05);
}

.image-of-the-day img {
  max-width: 100%;
  height: auto;
  border: 1px solid var(--color-border-medium);
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.image-of-the-day figcaption {
  font-size: 0.85rem;
  color: var(--color-text-light);
  margin-top: var(--spacing-xs);
  font-style: italic;
  font-family: var(--font-serif);
}

/* ===== Footer ===== */
footer {
  text-align: center;
  font-size: 0.8rem;
  color: var(--color-text-lightest);
  border-top: 1px solid var(--color-border-medium);
  padding: var(--spacing-lg) var(--spacing-sm);
  margin-top: var(--spacing-lg);
  font-family: var(--font-serif);
}

/* ===== Post Pages ===== */
.post-header {
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-sm);
  border-bottom: 2px solid var(--color-dark);
}

.post-header h1 {
  font-family: var(--font-serif);
  font-size: 2rem;
  margin-bottom: var(--spacing-xs);
  text-transform: none;
  letter-spacing: normal;
}

.post-header time {
  font-size: 0.9rem;
  color: var(--color-text-lighter);
  font-style: italic;
}

.post-body {
  margin-top: var(--spacing-lg);
}

.post-body h3 {
  font-family: var(--font-serif);
  font-size: 1.4rem;
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
  padding-top: var(--spacing-xs);
  scroll-margin-top: 100px;
}

.post-body h3:first-of-type {
  margin-top: 0;
}

.post-body h3 .reading-time {
  font-size: 0.9rem;
  color: var(--color-text-lighter);
  font-weight: normal;
}

.post-body p {
  text-align: justify;
  margin: 0.8rem 0;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  line-height: 1.7;
}

.post-body a {
  color: var(--color-text-light);
  text-decoration: none;
  border-bottom: 1px dotted var(--color-border-dark);
  transition: var(--transition-default);
}

.post-body a:hover {
  color: var(--color-dark);
  border-bottom-color: var(--color-dark);
}

/* ===== Responsive Design ===== */
@media (max-width: 960px) {
  main,
  .post-content {
    padding: 0 var(--spacing-sm);
  }

  nav a {
    display: inline-block;
    margin: 0.3rem 0.7rem;
  }
}

/* ===== Mobile Adjustments ===== */
@media (max-width: 768px) {
  .floating-nav {
    padding: var(--spacing-xs);
  }

  .floating-menu-toggle {
    font-size: 0.85rem;
    padding: var(--spacing-xs) 0.8rem;
  }

  .floating-nav .toc-list {
    min-width: calc(100vw - 2rem);
    max-width: calc(100vw - 2rem);
    right: var(--spacing-xs);
  }
}

@media (max-width: 600px) {
  header h1 {
    font-size: 2rem;
  }

  section h2 {
    font-size: 1.2rem;
  }

  body {
    font-size: 0.9rem;
  }

  article h3 {
    font-size: 1rem;
  }
}

.post-header .total-reading-time {
  font-size: 0.9rem;
  color: var(--color-text-lighter);
  font-style: italic;
  margin-top: 0.5rem;
}

.post-meta {
  font-size: 0.9rem;
  color: var(--color-text-lighter);
  font-style: italic;
  margin-bottom: 0.5rem;
}

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

footer a:hover {
  text-decoration: underline;
}