/* ============================================
   TotyLabs Landing Page - Styles
   ============================================ */

/* Design Tokens */
:root {
  /* Colors */
  --color-primary: #36d1c4;
  --color-primary-dark: #12a89b;
  --color-accent: #7c3aed;
  --color-success: #22c55e;
  --color-error: #ef4444;

  /* Light Mode */
  --color-bg-light: #ffffff;
  --color-bg-light-secondary: #f8fafc;
  --color-text-light: #0f172a;
  --color-text-light-muted: #64748b;
  --color-border-light: #e2e8f0;

  /* Dark Mode */
  --color-bg-dark: #0e1116;
  --color-bg-dark-secondary: #161b22;
  --color-text-dark: #e5e7eb;
  --color-text-dark-muted: #9ca3af;
  --color-border-dark: #30363d;

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;

  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 16px;

  /* Typography */
  --font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, sans-serif;
  --font-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, "Courier New", monospace;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);

  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-base: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
}

/* Light Mode (default) */
:root {
  --bg: var(--color-bg-light);
  --bg-secondary: var(--color-bg-light-secondary);
  --text: var(--color-text-light);
  --text-muted: var(--color-text-light-muted);
  --border: var(--color-border-light);
}

/* Dark Mode */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: var(--color-bg-dark);
    --bg-secondary: var(--color-bg-dark-secondary);
    --text: var(--color-text-dark);
    --text-muted: var(--color-text-dark-muted);
    --border: var(--color-border-dark);
  }
}

/* Dark mode toggle override */
html.dark-mode {
  --bg: var(--color-bg-dark);
  --bg-secondary: var(--color-bg-dark-secondary);
  --text: var(--color-text-dark);
  --text-muted: var(--color-text-dark-muted);
  --border: var(--color-border-dark);
}

html.light-mode {
  --bg: var(--color-bg-light);
  --bg-secondary: var(--color-bg-light-secondary);
  --text: var(--color-text-light);
  --text-muted: var(--color-text-light-muted);
  --border: var(--color-border-light);
}

/* ============================================
   Base Styles
   ============================================ */

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.6;
  transition: background-color var(--transition-base), color var(--transition-base);
}

/* ============================================
   Typography
   ============================================ */

h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
}

h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
}

h2 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
}

h3 {
  font-size: clamp(1.25rem, 3vw, 1.75rem);
}

p {
  margin-bottom: var(--spacing-md);
  color: var(--text-muted);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-dark);
}

/* ============================================
   Layout
   ============================================ */

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.grid {
  display: grid;
  gap: var(--spacing-2xl);
  margin-bottom: var(--spacing-2xl);
}

.grid--2 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid--3 {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

@media (max-width: 768px) {
  .grid--2,
  .grid--3 {
    grid-template-columns: 1fr;
  }
}

/* ============================================
   Navigation
   ============================================ */

.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  transition: all var(--transition-base);
}

@media (prefers-color-scheme: dark) {
  .navbar {
    background: rgba(14, 17, 22, 0.8);
  }
}

html.light-mode .navbar {
  background: rgba(255, 255, 255, 0.8);
}

html.dark-mode .navbar {
  background: rgba(14, 17, 22, 0.8);
}

.navbar__content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-md) var(--spacing-lg);
  gap: var(--spacing-lg);
}

.navbar__logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--text);
  transition: color var(--transition-fast);
}

.navbar__logo:hover {
  color: var(--color-primary);
}

.logo {
  width: 32px;
  height: 32px;
  color: var(--color-primary);
}

.navbar__brand {
  display: none;
}

@media (min-width: 640px) {
  .navbar__brand {
    display: inline;
  }
}

.navbar__menu {
  display: none;
  list-style: none;
  gap: var(--spacing-lg);
  flex: 1;
  margin: 0 var(--spacing-xl);
}

@media (min-width: 1024px) {
  .navbar__menu {
    display: flex;
  }
}

.navbar__link {
  color: var(--text-muted);
  font-size: 0.95rem;
  transition: color var(--transition-fast);
}

.navbar__link:hover {
  color: var(--color-primary);
}

.navbar__actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.navbar__toggle {
  display: flex;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-sm);
}

@media (min-width: 1024px) {
  .navbar__toggle {
    display: none;
  }
}

.navbar__toggle span {
  width: 24px;
  height: 2px;
  background-color: var(--text);
  transition: all var(--transition-fast);
  border-radius: 1px;
}

.navbar__toggle[aria-expanded="true"] span:nth-child(1) {
  transform: rotate(45deg) translate(8px, 8px);
}

.navbar__toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.navbar__toggle[aria-expanded="true"] span:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -7px);
}

/* ============================================
   Buttons
   ============================================ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-lg);
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  white-space: nowrap;
}

.btn--primary {
  background-color: var(--color-primary);
  color: var(--color-bg-dark);
  border-color: var(--color-primary);
}

.btn--primary:hover {
  background-color: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 8px 16px rgba(54, 209, 196, 0.3);
}

.btn--ghost {
  background-color: transparent;
  color: var(--text);
  border-color: var(--border);
}

.btn--ghost:hover {
  background-color: var(--bg-secondary);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn--sm {
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: 0.85rem;
}

.btn--lg {
  padding: var(--spacing-lg) var(--spacing-2xl);
  font-size: 1.05rem;
}

.btn--block {
  width: 100%;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* ============================================
   Hero Section
   ============================================ */

.hero {
  padding: var(--spacing-3xl) var(--spacing-lg);
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: linear-gradient(135deg, var(--bg) 0%, var(--bg-secondary) 100%);
}

.hero .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-3xl);
  align-items: center;
}

@media (max-width: 768px) {
  .hero .container {
    grid-template-columns: 1fr;
  }
}

.hero__content {
  z-index: 2;
}

.hero__title {
  font-size: clamp(2rem, 6vw, 3.5rem);
  line-height: 1.1;
  margin-bottom: var(--spacing-lg);
  background: linear-gradient(135deg, var(--text) 0%, var(--color-primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  margin-bottom: var(--spacing-2xl);
  max-width: 500px;
}

.hero__ctas {
  display: flex;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-2xl);
  flex-wrap: wrap;
}

@media (max-width: 640px) {
  .hero__ctas {
    flex-direction: column;
  }

  .hero__ctas .btn {
    width: 100%;
  }
}

.hero__badges {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.hero__visual {
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.floating-logo {
  animation: float 6s ease-in-out infinite;
}

@keyframes float {
  0%,
  100% {
    transform: translateY(0px);
  }
  50% {
    transform: translateY(-20px);
  }
}

/* ============================================
   Sections
   ============================================ */

.section {
  padding: var(--spacing-3xl) var(--spacing-lg);
}

.section__title {
  text-align: center;
  margin-bottom: var(--spacing-md);
}

.section__subtitle {
  text-align: center;
  color: var(--text-muted);
  font-size: 1.1rem;
  margin-bottom: var(--spacing-3xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.section__cta {
  text-align: center;
  margin-top: var(--spacing-3xl);
}

/* ============================================
   Cards
   ============================================ */

.card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-2xl);
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
}

.card:hover {
  border-color: var(--color-primary);
  box-shadow: 0 12px 24px rgba(54, 209, 196, 0.15);
  transform: translateY(-4px);
}

.card--pillar {
  text-align: center;
}

.card__icon {
  width: 60px;
  height: 60px;
  margin: 0 auto var(--spacing-lg);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
}

.card__icon-large {
  width: 80px;
  height: 80px;
  margin-bottom: var(--spacing-lg);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
}

.card__title {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-sm);
}

.card__subtitle {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: var(--spacing-md);
}

.card__description {
  color: var(--text-muted);
  margin-bottom: var(--spacing-lg);
  flex-grow: 1;
}

.card__header {
  margin-bottom: var(--spacing-lg);
}

.card__body {
  flex-grow: 1;
  margin-bottom: var(--spacing-lg);
}

.card__footer {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.card__features {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
  margin-bottom: var(--spacing-md);
}

.card__tech {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.card--product {
  display: flex;
  flex-direction: column;
}

.card--product .card__footer {
  margin-top: auto;
}

.card--coming-soon {
  opacity: 0.7;
}

.card--service {
  text-align: center;
}

.card__price {
  font-size: 1.25rem;
  color: var(--color-primary);
  margin: var(--spacing-lg) 0;
}

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

.card--case {
  border-left: 4px solid var(--color-primary);
}

.card__problem,
.card__solution {
  margin-bottom: var(--spacing-md);
  color: var(--text-muted);
}

.card__kpis {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--border);
}

.kpi {
  text-align: center;
}

.kpi__value {
  display: block;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-primary);
}

.kpi__label {
  display: block;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.card--blog {
  display: flex;
  flex-direction: column;
}

.card__meta {
  display: flex;
  gap: var(--spacing-md);
  align-items: center;
  margin-bottom: var(--spacing-md);
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ============================================
   Badges & Chips
   ============================================ */

.badge {
  display: inline-block;
  background-color: rgba(54, 209, 196, 0.1);
  color: var(--color-primary);
  padding: var(--spacing-xs) var(--spacing-md);
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  font-weight: 600;
  border: 1px solid var(--color-primary);
}

.badge--accent {
  background-color: rgba(124, 58, 237, 0.1);
  color: var(--color-accent);
  border-color: var(--color-accent);
}

.chip {
  display: inline-block;
  background-color: var(--bg);
  color: var(--text);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  border: 1px solid var(--border);
  transition: all var(--transition-fast);
}

.chip:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.chip--tech {
  background-color: rgba(54, 209, 196, 0.05);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.tag {
  display: inline-block;
  background-color: rgba(124, 58, 237, 0.1);
  color: var(--color-accent);
  padding: var(--spacing-xs) var(--spacing-md);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 600;
}

/* ============================================
   Links
   ============================================ */

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  color: var(--color-primary);
  font-weight: 600;
  transition: all var(--transition-fast);
}

.link-arrow:hover {
  gap: var(--spacing-md);
}

/* ============================================
   OSS Section
   ============================================ */

.oss__content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-3xl);
  align-items: center;
}

@media (max-width: 768px) {
  .oss__content {
    grid-template-columns: 1fr;
  }
}

.repos-list {
  list-style: none;
  margin-bottom: var(--spacing-2xl);
}

.repos-list li {
  padding: var(--spacing-md) 0;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
}

.repos-list a {
  color: var(--color-primary);
  font-weight: 600;
}

.oss__actions {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

/* ============================================
   Security Section
   ============================================ */

.security__block {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-2xl);
}

.security__block h3 {
  color: var(--color-primary);
  margin-bottom: var(--spacing-lg);
}

.security__list {
  list-style: none;
}

.security__list li {
  padding: var(--spacing-sm) 0;
  padding-left: var(--spacing-lg);
  position: relative;
  color: var(--text-muted);
}

.security__list li:before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--color-success);
  font-weight: 700;
}

/* ============================================
   Tech Stack Section
   ============================================ */

.tech-stack__grid {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  justify-content: center;
}

/* ============================================
   Newsletter Section
   ============================================ */

.newsletter {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: var(--color-bg-dark);
}

.newsletter__content {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.newsletter__title {
  color: var(--color-bg-dark);
  margin-bottom: var(--spacing-md);
}

.newsletter__subtitle {
  color: rgba(14, 17, 22, 0.8);
  margin-bottom: var(--spacing-2xl);
}

.newsletter__form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

@media (min-width: 640px) {
  .newsletter__form {
    flex-direction: row;
  }
}

.newsletter__form input {
  flex: 1;
  padding: var(--spacing-md) var(--spacing-lg);
  border: none;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.1);
  color: var(--color-bg-dark);
  font-family: var(--font-family);
}

.newsletter__form input::placeholder {
  color: rgba(14, 17, 22, 0.6);
}

.newsletter__form button {
  background: var(--color-bg-dark);
  color: var(--color-primary);
  border: none;
}

.newsletter__form button:hover {
  background: rgba(14, 17, 22, 0.9);
}

.newsletter__message {
  color: rgba(14, 17, 22, 0.8);
  font-size: 0.9rem;
}

/* ============================================
   FAQ Section
   ============================================ */

.faq__list {
  max-width: 800px;
  margin: 0 auto;
}

.faq__item {
  border-bottom: 1px solid var(--border);
  padding: var(--spacing-lg) 0;
}

.faq__item:last-child {
  border-bottom: none;
}

.faq__question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  font-weight: 600;
  color: var(--text);
  user-select: none;
  transition: color var(--transition-fast);
}

.faq__question:hover {
  color: var(--color-primary);
}

.faq__question::after {
  content: "▼";
  font-size: 0.75rem;
  transition: transform var(--transition-fast);
  color: var(--color-primary);
}

.faq__item[open] .faq__question::after {
  transform: rotate(180deg);
}

.faq__answer {
  padding: var(--spacing-lg) 0;
  color: var(--text-muted);
}

.faq__answer p {
  margin-bottom: var(--spacing-md);
}

/* ============================================
   About Section
   ============================================ */

.about__content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-3xl);
  align-items: center;
}

@media (max-width: 768px) {
  .about__content {
    grid-template-columns: 1fr;
  }
}

.about__text h3,
.about__team h3 {
  color: var(--color-primary);
  margin-top: var(--spacing-2xl);
  margin-bottom: var(--spacing-md);
}

.about__text h3:first-child,
.about__team h3:first-child {
  margin-top: 0;
}

.about__values {
  list-style: none;
  margin-top: var(--spacing-lg);
}

.about__values li {
  padding: var(--spacing-md) 0;
  color: var(--text-muted);
}

.about__values strong {
  color: var(--text);
}

/* ============================================
   Contact Section
   ============================================ */

.contact__form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.form__group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.form__group label {
  font-weight: 600;
  color: var(--text);
}

.form__group input,
.form__group textarea {
  padding: var(--spacing-md) var(--spacing-lg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--bg-secondary);
  color: var(--text);
  font-family: var(--font-family);
  transition: border-color var(--transition-fast);
}

.form__group input:focus,
.form__group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(54, 209, 196, 0.1);
}

.contact__message {
  text-align: center;
  font-size: 0.9rem;
  color: var(--color-success);
}

.contact__info {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.contact__card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
}

.contact__card h3 {
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
}

.contact__card p {
  margin: 0;
}

.contact__card a {
  color: var(--color-primary);
  font-weight: 600;
}

.social-links {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.social-links a {
  display: inline-block;
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.social-links a:hover {
  background: var(--color-primary);
  color: var(--color-bg-dark);
  border-color: var(--color-primary);
}

/* ============================================
   Footer
   ============================================ */

.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: var(--spacing-3xl) var(--spacing-lg);
  margin-top: var(--spacing-3xl);
}

.footer__content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-2xl);
  margin-bottom: var(--spacing-2xl);
}

.footer__column h4 {
  color: var(--text);
  margin-bottom: var(--spacing-lg);
  font-size: 0.95rem;
}

.footer__column ul {
  list-style: none;
}

.footer__column li {
  margin-bottom: var(--spacing-md);
}

.footer__column a {
  color: var(--text-muted);
  transition: color var(--transition-fast);
}

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

.footer__bottom {
  text-align: center;
  padding-top: var(--spacing-2xl);
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer__note {
  margin-top: var(--spacing-md);
}

/* ============================================
   Theme Toggle
   ============================================ */

.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-sm);
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: color var(--transition-fast);
}

.theme-toggle:hover {
  color: var(--color-primary);
}

.icon-sun,
.icon-moon {
  width: 20px;
  height: 20px;
  transition: opacity var(--transition-fast);
}

.icon-moon {
  display: none;
}

@media (prefers-color-scheme: dark) {
  .icon-sun {
    display: none;
  }

  .icon-moon {
    display: block;
  }
}

html.dark-mode .icon-sun {
  display: none;
}

html.dark-mode .icon-moon {
  display: block;
}

html.light-mode .icon-sun {
  display: block;
}

html.light-mode .icon-moon {
  display: none;
}

/* ============================================
   Back to Top Button
   ============================================ */

.back-to-top {
  position: fixed;
  bottom: var(--spacing-lg);
  right: var(--spacing-lg);
  width: 48px;
  height: 48px;
  background: var(--color-primary);
  color: var(--color-bg-dark);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-base);
  z-index: 999;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: var(--color-primary-dark);
  transform: translateY(-4px);
}

/* ============================================
   Utilities
   ============================================ */

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

.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;
}

/* ============================================
   Responsive
   ============================================ */

@media (max-width: 640px) {
  .container {
    padding: 0 var(--spacing-md);
  }

  .section {
    padding: var(--spacing-2xl) var(--spacing-md);
  }

  .hero {
    padding: var(--spacing-2xl) var(--spacing-md);
    min-height: auto;
  }

  .hero__visual {
    margin-top: var(--spacing-2xl);
  }
}

/* ============================================
   Print Styles
   ============================================ */

@media print {
  .navbar,
  .back-to-top,
  .theme-toggle {
    display: none;
  }
}