:root {
  --pd-card-radius: 8px;
  --pd-card-margin: 1rem 0;
  --pd-surface-bg: var(--md-code-bg-color);
  --pd-surface-border: 1px solid var(--md-default-fg-color--lightest);
  --pd-hero-bg: linear-gradient(135deg, #f5f0e6 0%, #faf7f0 50%, #fffef9 100%);
  --pd-hero-text: #2d2a26;
  --pd-accent: #8b6914;
  --pd-accent-dark: #6b5210;
  --pd-accent-cool: #4a90d9;
  --pd-accent-cool-dark: #3b7fc4;
}

/* Navigation Bar */
[data-md-color-scheme="default"] .md-header {
  background-color: #e8dcc8;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.12);
}

[data-md-color-scheme="default"] .md-header__title,
[data-md-color-scheme="default"] .md-header-nav__button,
[data-md-color-scheme="default"] .md-header__button {
  color: #2d2a26;
}

[data-md-color-scheme="slate"] .md-header__title,
[data-md-color-scheme="slate"] .md-header-nav__button,
[data-md-color-scheme="slate"] .md-header__button {
  color: #f5f2ec;
}

.md-header__title {
  font-weight: 700;
  letter-spacing: 0.01em;
}

[data-md-color-scheme="default"] .md-tabs {
  background-color: #d9ccb8;
}

.md-tabs__link {
  color: #2f2a26;
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.02em;
}

.md-tabs__link--active,
.md-tabs__link:hover {
  color: #1e1b19;
  font-weight: 700;
}

[data-md-color-scheme="slate"] .md-tabs__link {
  color: rgba(245, 242, 236, 0.9);
}

[data-md-color-scheme="slate"] .md-tabs__link--active,
[data-md-color-scheme="slate"] .md-tabs__link:hover {
  color: #ffffff;
}

[data-md-color-scheme="default"] .md-search__input {
  background-color: rgba(255, 255, 255, 0.7);
  color: #2d2a26;
  font-weight: 500;
}

[data-md-color-scheme="default"] .md-search__input::placeholder {
  color: #4a4540;
}

[data-md-color-scheme="slate"] .md-search__input {
  background-color: rgba(255, 255, 255, 0.08);
  color: #f5f2ec;
  font-weight: 500;
}

[data-md-color-scheme="slate"] .md-search__input::placeholder {
  color: rgba(245, 242, 236, 0.7);
}

/* Repo/source text in header */
[data-md-color-scheme="default"] .md-source,
[data-md-color-scheme="default"] .md-source__repository,
[data-md-color-scheme="default"] .md-source__facts,
[data-md-color-scheme="default"] .md-source__fact,
[data-md-color-scheme="default"] .md-header__source,
[data-md-color-scheme="default"] .md-header__source a {
  color: #2d2a26;
  font-weight: 500;
}

[data-md-color-scheme="default"] .md-source__repository {
  font-weight: 600;
}

[data-md-color-scheme="slate"] .md-source,
[data-md-color-scheme="slate"] .md-source__repository,
[data-md-color-scheme="slate"] .md-source__facts,
[data-md-color-scheme="slate"] .md-source__fact,
[data-md-color-scheme="slate"] .md-header__source,
[data-md-color-scheme="slate"] .md-header__source a {
  color: #f5f2ec;
  font-weight: 500;
}

/* Hero Section */
.hero-section {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  background: var(--pd-hero-bg);
  border-radius: 16px;
  padding: 3rem;
  margin: -1rem -0.5rem 2rem -0.5rem;
  min-height: 320px;
  overflow: hidden;
  position: relative;
  box-shadow: 0 10px 40px rgba(13, 71, 161, 0.3);
}

.hero-section::before {
  content: "";
  position: absolute;
  top: -50%;
  right: -20%;
  width: 60%;
  height: 200%;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 60%);
  pointer-events: none;
}

.hero-content {
  flex: 1;
  max-width: 55%;
  z-index: 1;
}

.hero-title {
  font-size: 2.75rem !important;
  font-weight: 800 !important;
  color: var(--pd-hero-text) !important;
  margin: 0 0 1rem 0 !important;
  line-height: 1.2 !important;
  letter-spacing: 0.005em;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.hero-subtitle {
  font-size: 1.15rem;
  color: rgba(45, 42, 38, 0.8);
  margin: 0 0 2rem 0;
  line-height: 1.7;
  max-width: 90%;
}

.hero-button {
  display: inline-block;
  padding: 1rem 2.5rem;
  background: var(--pd-accent);
  color: #ffffff !important;
  font-weight: 700;
  font-size: 1.1rem;
  text-decoration: none !important;
  border-radius: 50px;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(139, 105, 20, 0.3);
}

.hero-button:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(139, 105, 20, 0.4);
  background: var(--pd-accent-dark);
}

.hero-image {
  flex: 0 0 40%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  z-index: 1;
  text-align: center;
}

.hero-image img {
  width: 180px;
  height: 180px;
  object-fit: cover;
  border-radius: 50%;
  border: 4px solid rgba(139, 119, 101, 0.3);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
  margin-bottom: 1rem;
}

.hero-image img,
.hero-quote,
.hero-quote-author {
  transition: opacity 0.25s ease;
}

.hero-quote {
  font-size: 1rem;
  font-style: italic;
  color: rgba(45, 42, 38, 0.85);
  margin: 0 0 0.5rem 0;
  line-height: 1.5;
  max-width: 280px;
}

.hero-quote-author {
  font-size: 0.9rem;
  color: rgba(45, 42, 38, 0.7);
  font-weight: 500;
}

/* Hero responsive */
@media (max-width: 768px) {
  .hero-section {
    flex-direction: column;
    text-align: center;
    padding: 2rem 1.5rem;
  }

  .hero-content {
    max-width: 100%;
    margin-bottom: 2rem;
  }

  .hero-title {
    font-size: 2rem !important;
  }

  .hero-subtitle {
    max-width: 100%;
  }

  .hero-image {
    flex: none;
    width: 100%;
  }

  .hero-image img {
    max-height: 200px;
  }
}

/* Hero Dark Mode */
[data-md-color-scheme="slate"] .hero-section {
  background: linear-gradient(135deg, #1e3a5f 0%, #2a4a6d 50%, #1a3350 100%);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
}

[data-md-color-scheme="slate"] .hero-title {
  color: #ffffff !important;
}

[data-md-color-scheme="slate"] .hero-subtitle {
  color: rgba(255, 255, 255, 0.85);
}

[data-md-color-scheme="slate"] .hero-button {
  background: var(--pd-accent-cool);
  box-shadow: 0 4px 15px rgba(74, 144, 217, 0.3);
}

[data-md-color-scheme="slate"] .hero-button:hover {
  background: var(--pd-accent-cool-dark);
  box-shadow: 0 8px 25px rgba(74, 144, 217, 0.4);
}

[data-md-color-scheme="slate"] .hero-image img {
  border-color: rgba(255, 255, 255, 0.2);
}

[data-md-color-scheme="slate"] .hero-quote {
  color: rgba(255, 255, 255, 0.9);
}

[data-md-color-scheme="slate"] .hero-quote-author {
  color: rgba(255, 255, 255, 0.7);
}

/* Topic Hero (section headers) */
.topic-hero {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.25rem;
  padding: 1.25rem 1.5rem;
  border-radius: 12px;
  border: 1px solid rgba(0, 0, 0, 0.06);
  background: linear-gradient(120deg, #f6efe2 0%, #ffffff 100%);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.06);
  margin: 0 0 1.5rem 0;
}

.topic-hero-text h1 {
  margin: 0 0 0.35rem 0;
  font-size: 1.9rem;
  font-weight: 800;
}

.topic-hero-kicker {
  margin: 0;
  font-size: 0.95rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #6b5b45;
  font-weight: 700;
}

.topic-hero-subtitle {
  margin: 0 0 0.75rem 0;
  color: #4a4337;
  line-height: 1.55;
}

.topic-hero-button {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.6rem 1.1rem;
  background: var(--pd-accent);
  color: #ffffff !important;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.95rem;
  text-decoration: none !important;
  box-shadow: 0 3px 12px rgba(139, 105, 20, 0.35);
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.topic-hero-button::after {
  content: "->";
  font-size: 0.9rem;
}

.topic-hero-button:hover {
  transform: translateY(-1px);
  background: var(--pd-accent-dark);
  box-shadow: 0 6px 15px rgba(107, 82, 16, 0.35);
}

/* Topic Hero Dark Mode */
[data-md-color-scheme="slate"] .topic-hero {
  border-color: rgba(255, 255, 255, 0.08);
  background: linear-gradient(120deg, rgba(58, 92, 146, 0.85) 0%, rgba(24, 41, 66, 0.95) 100%);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
}

[data-md-color-scheme="slate"] .topic-hero-text h1 {
  color: #ffffff;
}

[data-md-color-scheme="slate"] .topic-hero-subtitle {
  color: rgba(245, 242, 236, 0.92);
}

[data-md-color-scheme="slate"] .topic-hero-kicker {
  color: rgba(245, 242, 236, 0.8);
}

[data-md-color-scheme="slate"] .topic-hero-button {
  background: var(--pd-accent-cool);
  box-shadow: 0 3px 12px rgba(74, 144, 217, 0.35);
}

[data-md-color-scheme="slate"] .topic-hero-button:hover {
  background: var(--pd-accent-cool-dark);
  box-shadow: 0 6px 18px rgba(59, 127, 196, 0.4);
}

/* Better equation spacing */
.md-typeset .arithmatex {
  overflow-x: auto;
  padding: 0.5rem 0;
}

/* Important equations box */
.important-equation {
  background: linear-gradient(135deg, var(--md-primary-fg-color--dark) 0%, var(--md-primary-fg-color) 100%);
  color: var(--md-primary-bg-color);
  padding: 1.5rem;
  border-radius: var(--pd-card-radius);
  margin: 1.5rem 0;
  text-align: center;
}

.important-equation .MathJax {
  font-size: 1.2em !important;
}

/* Vector notation */
.vector {
  font-weight: bold;
}

/* Unit highlighting */
.unit {
  color: var(--md-accent-fg-color);
}

/* Clickable Grid Cards for Homepage */
.clickable-cards>ul {
  gap: 1.5rem;
}

.clickable-cards>ul>li {
  background-color: var(--md-default-bg-color);
  /* Correct background for dark mode */
  border: 1px solid var(--md-default-fg-color--lightest);
  border-radius: 12px;
  padding: 1.5rem;
  transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
  /* Smoother transition */
  position: relative;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
  /* Subtle shadow for light mode */
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  height: 100%;
}

/* Dark mode specific adjustments */
[data-md-color-scheme="slate"] .clickable-cards>ul>li {
  background-color: var(--md-card-bg-color, #1e1e2e);
  /* Ensure darker bg in dark mode */
  border-color: var(--md-default-fg-color--lighter);
  box-shadow: none;
  /* No shadow needed in dark mode usually */
}

/* Floating Hover Effect */
.clickable-cards>ul>li:hover {
  transform: translateY(-3px);
  /* Subtle movement */
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  border-color: var(--md-accent-fg-color);
  z-index: 2;
}

.clickable-cards>ul>li:focus-within {
  transform: translateY(-3px);
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  border-color: var(--md-accent-fg-color);
}

/* Dark mode hover */
[data-md-color-scheme="slate"] .clickable-cards>ul>li:hover {
  background-color: var(--md-code-bg-color);
  /* Slightly lighter on hover in dark mode */
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
  /* Stronger shadow for dark mode visibility */
}

/* Enhancing Icons inside cards */
.clickable-cards>ul>li .lg {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  color: var(--md-accent-fg-color);
  transition: transform 0.3s ease;
  display: inline-block;
}

.clickable-cards>ul>li:hover .lg {
  transform: scale(1.1);
  /* Removed rotation */
}

/* Link Stretched Overlay */
.clickable-cards>ul>li a {
  text-decoration: none;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--md-default-fg-color);
  display: block;
  margin-bottom: 0.5rem;
  font-family: var(--md-font-heading, serif);
}

.clickable-cards>ul>li a::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 10;
  cursor: pointer;
}

.hero-button:focus-visible,
.topic-hero-button:focus-visible,
.md-tabs__link:focus-visible,
.md-header__button:focus-visible,
.clickable-cards>ul>li a:focus-visible {
  outline: 2px solid var(--md-accent-fg-color);
  outline-offset: 3px;
}

/* Title hover color */
.clickable-cards>ul>li:hover a {
  color: var(--md-accent-fg-color);
}

/* Text content inside card */
.clickable-cards>ul>li p {
  font-size: 0.95rem;
  color: var(--md-default-fg-color--light);
  line-height: 1.5;
  margin: 0;
}

/* Hide left chapter navigation sidebar */
@media screen and (min-width: 76.25em) {
  .md-sidebar--primary {
    display: none;
  }

  /* Remove extra spacing applied when the sidebar exists */
  [dir=ltr] .md-sidebar--primary:not([hidden])~.md-content>.md-content__inner {
    margin-left: 0;
  }

  /* Drawer toggle is useless without navigation */
  label.md-header__button[for="__drawer"] {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .hero-button,
  .hero-image img,
  .hero-quote,
  .hero-quote-author,
  .topic-hero-button,
  .clickable-cards>ul>li,
  .clickable-cards>ul>li .lg {
    transition: none;
  }

  .hero-button:hover,
  .topic-hero-button:hover,
  .clickable-cards>ul>li:hover,
  .clickable-cards>ul>li:focus-within {
    transform: none;
  }
}