/* 1. CSS Variables & Theme Setup
------------------------------------------------------------------- */
:root {
  --font-primary: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji",
    "Segoe UI Symbol";
  --font-secondary: "Georgia", serif;

  /* Light Theme */
  --color-background: #f8f9fa;
  --color-surface: #ffffff;
  --color-primary: #005f73;
  --color-primary-dark: #003e4d;
  --color-secondary: #0a9396;
  --color-accent: #94d2bd;
  --color-text-primary: #212529;
  --color-text-secondary: #495057;
  --color-border: #dee2e6;
  --color-shadow: rgba(0, 0, 0, 0.08);
  --color-success: #2a9d8f;
  --color-success-background: #e9f5f4;
  --color-icon: #005f73;

  /* Spacing & Sizing */
  --spacing-xs: 4px;
  --spacing-s: 8px;
  --spacing-m: 16px;
  --spacing-l: 24px;
  --spacing-xl: 32px;
  --spacing-xxl: 64px;
  --container-width: 1200px;
  --header-height: 70px;

  /* Borders & Shadows */
  --border-radius-s: 4px;
  --border-radius-m: 8px;
  --box-shadow-light: 0 4px 6px var(--color-shadow);
  --box-shadow-medium: 0 8px 24px var(--color-shadow);

  /* Transitions */
  --transition-fast: 0.2s ease-in-out;
  --transition-medium: 0.4s ease-in-out;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-background: #121212;
    --color-surface: #1e1e1e;
    --color-primary: #94d2bd;
    --color-primary-dark: #e9f5f4;
    --color-secondary: #0a9396;
    --color-accent: #005f73;
    --color-text-primary: #e0e0e0;
    --color-text-secondary: #adb5bd;
    --color-border: #343a40;
    --color-shadow: rgba(0, 0, 0, 0.25);
    --color-success: #94d2bd;
    --color-success-background: #2c3e3c;
    --color-icon: #94d2bd;
  }
}

/* 2. Reset & Global Styles
------------------------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-primary);
  background-color: var(--color-background);
  color: var(--color-text-primary);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--transition-fast),
    color var(--transition-fast);
}

.container {
  width: 90%;
  max-width: var(--container-width);
  margin-left: auto;
  margin-right: auto;
}

section {
  padding-top: var(--spacing-xxl);
  padding-bottom: var(--spacing-xxl);
}

h1,
h2,
h3,
h4 {
  color: var(--color-primary);
  line-height: 1.3;
  font-weight: 700;
  margin-bottom: var(--spacing-l);
  transition: color var(--transition-fast);
}

h1 {
  font-size: 2.8rem;
  letter-spacing: -1px;
}

h2 {
  font-size: 2.2rem;
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

h3 {
  font-size: 1.5rem;
  margin-bottom: var(--spacing-m);
}

h4 {
  font-size: 1.2rem;
}

p {
  margin-bottom: var(--spacing-m);
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
}

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

a:hover {
  color: var(--color-primary);
  text-decoration: underline;
}

ul {
  list-style: none;
}

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

.section-intro {
  text-align: center;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: var(--spacing-xxl);
  font-size: 1.1rem;
}

/* 3. Header & Navigation
------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background-color: color-mix(in srgb, var(--color-surface) 90%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  height: var(--header-height);
  transition: background-color var(--transition-fast),
    border-bottom var(--transition-fast);
}

.site-header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 100%;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-primary);
  text-decoration: none;
}

.main-navigation ul {
  display: flex;
  gap: var(--spacing-xl);
}

.main-navigation a {
  font-weight: 500;
  color: var(--color-text-primary);
  text-decoration: none;
  padding: var(--spacing-s) 0;
  position: relative;
}

.main-navigation a::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--color-secondary);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform var(--transition-fast);
}

.main-navigation a:hover::after {
  transform: scaleX(1);
  transform-origin: left;
}

.cta-button {
  display: inline-block;
  background-color: var(--color-primary);
  color: var(--color-surface);
  padding: var(--spacing-s) var(--spacing-l);
  border-radius: var(--border-radius-m);
  text-decoration: none;
  font-weight: 500;
  border: 2px solid transparent;
  transition: background-color var(--transition-fast),
    color var(--transition-fast), transform var(--transition-fast);
}

.cta-button:hover {
  background-color: var(--color-primary-dark);
  color: var(--color-surface);
  transform: translateY(-2px);
  text-decoration: none;
}

/* Mobile Nav Styles - Initially hidden */
.mobile-nav-toggle,
.mobile-navigation {
  display: none;
}

/* 4. Hero Section
------------------------------------------------------------------- */
.hero {
  text-align: center;
  padding-top: calc(var(--spacing-xxl) * 1.5);
  padding-bottom: calc(var(--spacing-xxl) * 1.5);
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.hero h1 {
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: var(--spacing-l);
}

.hero .subtitle {
  font-size: 1.25rem;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: var(--spacing-xl);
  color: var(--color-text-secondary);
}

.hero-cta {
  font-size: 1.1rem;
  padding: var(--spacing-m) var(--spacing-xl);
}

/* 5. Feature Section
------------------------------------------------------------------- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: var(--spacing-xl);
}

.feature-card {
  background-color: var(--color-surface);
  padding: var(--spacing-xl);
  border-radius: var(--border-radius-m);
  border: 1px solid var(--color-border);
  transition: transform var(--transition-fast),
    box-shadow var(--transition-fast);
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--box-shadow-medium);
}

.feature-card svg {
  width: 48px;
  height: 48px;
  color: var(--color-secondary);
  margin-bottom: var(--spacing-l);
}

.feature-card h3 {
  margin-bottom: var(--spacing-s);
}

.feature-card p:last-child {
  margin-bottom: 0;
}

/* 6. How It Works Section
------------------------------------------------------------------- */
.how-it-works-section {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.steps-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-xl);
  position: relative;
}

.step {
  text-align: center;
  padding: var(--spacing-l);
}

.step-number {
  width: 60px;
  height: 60px;
  background-color: var(--color-primary);
  color: var(--color-surface);
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 1.8rem;
  font-weight: 700;
  margin: 0 auto var(--spacing-l);
  border: 4px solid var(--color-accent);
}

/* 7. Interactive (Tabs) Section
------------------------------------------------------------------- */
.tabs-container {
  max-width: 900px;
  margin: 0 auto;
}

.tab-buttons {
  display: flex;
  justify-content: center;
  gap: var(--spacing-m);
  margin-bottom: var(--spacing-xl);
  flex-wrap: wrap;
}

.tab-button {
  padding: var(--spacing-m) var(--spacing-l);
  border: 2px solid var(--color-border);
  background-color: transparent;
  color: var(--color-text-secondary);
  font-size: 1rem;
  font-weight: 500;
  border-radius: var(--border-radius-m);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.tab-button:hover {
  background-color: var(--color-accent);
  color: var(--color-primary-dark);
  border-color: var(--color-accent);
}

.tab-button.active {
  background-color: var(--color-primary);
  color: var(--color-surface);
  border-color: var(--color-primary);
}

.tab-content {
  display: none;
  padding: var(--spacing-l);
  background-color: var(--color-surface);
  border-radius: var(--border-radius-m);
  border: 1px solid var(--color-border);
  animation: fadeIn 0.5s ease-in-out;
}

.tab-content.active {
  display: block;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* 8. Case Study Section
------------------------------------------------------------------- */
.case-study-section {
  background-color: var(--color-surface);
}

.case-study-content {
  display: flex;
  gap: var(--spacing-xxl);
  align-items: center;
}

.case-study-text {
  flex: 2;
}

.case-study-metrics {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xl);
}

.metric-item {
  background-color: var(--color-background);
  padding: var(--spacing-l);
  text-align: center;
  border-radius: var(--border-radius-m);
  border-left: 5px solid var(--color-secondary);
}

.metric-value {
  display: block;
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--color-primary);
}

.metric-label {
  font-size: 1rem;
  color: var(--color-text-secondary);
}

/* 9. Testimonials Section
------------------------------------------------------------------- */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-xl);
}

.testimonial-card {
  background-color: var(--color-surface);
  padding: var(--spacing-xl);
  border-radius: var(--border-radius-m);
  border: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.testimonial-quote {
  font-family: var(--font-secondary);
  font-size: 1.1rem;
  font-style: italic;
  flex-grow: 1;
  margin-bottom: var(--spacing-l);
  position: relative;
  padding-left: var(--spacing-l);
  border-left: 3px solid var(--color-accent);
}

.testimonial-author h4 {
  margin-bottom: var(--spacing-xs);
  font-size: 1.1rem;
}

.testimonial-author span {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
}

/* 10. FAQ (Accordion) Section
------------------------------------------------------------------- */
.accordion {
  max-width: 800px;
  margin: 0 auto;
}

.accordion-item {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius-m);
  margin-bottom: var(--spacing-m);
  overflow: hidden;
}

.accordion-item:last-child {
  margin-bottom: 0;
}

.accordion-header {
  width: 100%;
  background-color: transparent;
  padding: var(--spacing-l);
  text-align: left;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border: none;
  cursor: pointer;
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--color-text-primary);
}

.accordion-header svg {
  width: 24px;
  height: 24px;
  color: var(--color-secondary);
  transition: transform var(--transition-medium);
}

.accordion-header.active svg {
  transform: rotate(180deg);
}

.accordion-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-medium),
    padding var(--transition-medium);
}

.accordion-content p {
  padding: 0 var(--spacing-l) var(--spacing-l);
  margin: 0;
}

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

/* 11. CTA & Form Section
------------------------------------------------------------------- */
.cta-section {
  background-color: var(--color-primary-dark);
  color: var(--color-surface);
  text-align: center;
}

.cta-section h2 {
  color: var(--color-surface);
}

.cta-section p {
  color: var(--color-accent);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.register-form {
  display: flex;
  justify-content: center;
  gap: var(--spacing-m);
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-s);
  flex-wrap: wrap;
}

.register-form .form-group {
  flex-grow: 1;
}

.register-form input {
  min-width: 250px;
  width: 100%;
  padding: var(--spacing-m);
  font-size: 1rem;
  border-radius: var(--border-radius-m);
  border: 2px solid var(--color-border);
  background-color: var(--color-surface);
  color: var(--color-text-primary);
  transition: border-color var(--transition-fast),
    box-shadow var(--transition-fast);
}

.register-form input:focus {
  outline: none;
  border-color: var(--color-secondary);
  box-shadow: 0 0 0 3px
    color-mix(in srgb, var(--color-secondary) 30%, transparent);
}

.register-form .cta-button {
  background-color: var(--color-secondary);
  color: var(--color-primary-dark);
}

.register-form .cta-button:hover {
  background-color: var(--color-accent);
}

#form-thank-you {
  padding: var(--spacing-l);
  background-color: var(--color-success-background);
  color: var(--color-success);
  border-radius: var(--border-radius-m);
  border: 1px solid var(--color-success);
  max-width: 500px;
  margin: var(--spacing-xl) auto 0;
}

#form-thank-you h3 {
  color: var(--color-success);
  margin-bottom: var(--spacing-s);
}

.form-terms {
  font-size: 0.8rem;
  color: var(--color-text-secondary);
}

.form-terms a {
  color: var(--color-accent);
  text-decoration: underline;
}

/* 12. Footer
------------------------------------------------------------------- */
.site-footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding-top: var(--spacing-xxl);
  padding-bottom: var(--spacing-xl);
  color: var(--color-text-secondary);
  font-size: 0.9rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
}

.footer-column h4 {
  margin-bottom: var(--spacing-m);
  color: var(--color-text-primary);
  font-size: 1.1rem;
}

.footer-column.about p {
  font-size: 0.9rem;
}

.footer-column ul li {
  margin-bottom: var(--spacing-s);
}

.footer-column ul a {
  color: var(--color-text-secondary);
}

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

.footer-column.contact address {
  font-style: normal;
  line-height: 1.6;
}

.footer-bottom {
  text-align: center;
  border-top: 1px solid var(--color-border);
  padding-top: var(--spacing-xl);
}

/* 13. Animation on Scroll
------------------------------------------------------------------- */
.fade-in-section {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.fade-in-section.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* 14. Cookie Banner
------------------------------------------------------------------- */
.cookie-banner {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  box-shadow: 0 -4px 12px var(--color-shadow);
  padding: var(--spacing-l);
  z-index: 2000;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--spacing-l);
  transform: translateY(100%);
  animation: slideInUp 0.5s forwards ease-out;
}

@keyframes slideInUp {
  to {
    transform: translateY(0);
  }
}

.cookie-banner.hidden {
  display: none;
}

.cookie-banner-text {
  max-width: 800px;
  font-size: 0.9rem;
  color: var(--color-text-secondary);
}

.cookie-accept-button {
  white-space: nowrap;
  background-color: var(--color-primary);
  color: var(--color-surface);
  padding: var(--spacing-s) var(--spacing-l);
  border-radius: var(--border-radius-m);
  border: none;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 500;
  transition: background-color var(--transition-fast);
}

.cookie-accept-button:hover {
  background-color: var(--color-primary-dark);
}

/* 15. Responsive Design
------------------------------------------------------------------- */
@media (max-width: 992px) {
  .case-study-content {
    flex-direction: column;
  }

  .case-study-metrics {
    flex-direction: row;
    width: 100%;
    justify-content: space-around;
  }

  .metric-item {
    flex: 1;
  }
}

@media (max-width: 768px) {
  html {
    font-size: 15px;
  }

  h1 {
    font-size: 2.2rem;
  }

  h2 {
    font-size: 1.8rem;
  }

  section {
    padding-top: var(--spacing-xl);
    padding-bottom: var(--spacing-xl);
  }

  /* Mobile Navigation */
  .main-navigation {
    display: none;
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100%;
    height: calc(100vh - var(--header-height));
    background-color: var(--color-surface);
    flex-direction: column;
    justify-content: center;
    align-items: center;
    transform: translateX(100%);
    transition: transform 0.3s ease-in-out;
  }

  .main-navigation.is-active {
    display: flex;
    transform: translateX(0);
  }

  .main-navigation ul {
    flex-direction: column;
    text-align: center;
  }

  .main-navigation a {
    font-size: 1.5rem;
  }

  .mobile-nav-toggle {
    display: block;
    z-index: 1001;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-s);
  }

  .hamburger-icon {
    width: 28px;
    height: 20px;
    position: relative;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
  }

  .hamburger-icon span {
    display: block;
    width: 100%;
    height: 3px;
    background-color: var(--color-primary);
    border-radius: 2px;
    transition: transform 0.3s ease-in-out, opacity 0.3s ease-in-out;
  }

  .mobile-nav-toggle.is-active .hamburger-icon span:nth-child(1) {
    transform: translateY(8.5px) rotate(45deg);
  }
  .mobile-nav-toggle.is-active .hamburger-icon span:nth-child(2) {
    opacity: 0;
  }
  .mobile-nav-toggle.is-active .hamburger-icon span:nth-child(3) {
    transform: translateY(-8.5px) rotate(-45deg);
  }

  .site-header .cta-button {
    display: none; /* Hide in header, present in mobile menu if needed */
  }

  .register-form {
    flex-direction: column;
    align-items: stretch;
  }

  .register-form .form-group {
    width: 100%;
  }

  .register-form input {
    width: 100%;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .footer-column.about,
  .footer-column.contact {
    text-align: center;
  }

  .footer-column ul {
    padding: 0;
  }

  .cookie-banner {
    flex-direction: column;
    text-align: center;
  }
}

@media (min-width: 1400px) {
  html {
    font-size: 17px;
  }

  :root {
    --container-width: 1300px;
  }
}