/* Stripe Design System - Dandy */

/* === CSS Variables === */
:root {
  /* Core Brand */
  --stripe-purple: #635BFF;
  --stripe-blue: #0A2540;
  --stripe-cyan: #00D4FF;

  /* Background Colors */
  --bg-dark: #0A2540;
  --bg-light: #F6F9FC;
  --bg-white: #FFFFFF;

  /* Text Colors */
  --text-primary: #0A2540;
  --text-secondary: #425466;
  --text-tertiary: #8898AA;
  --text-on-dark: #FFFFFF;
  --text-on-dark-muted: #ADBDCC;

  /* Accent Colors */
  --accent-green: #00D924;
  --accent-yellow: #FFBB00;
  --accent-orange: #FF6B00;
  --accent-pink: #FF57B2;
  --accent-red: #ED5F74;

  /* Gray Scale */
  --gray-50: #F6F9FC;
  --gray-100: #E3E8EE;
  --gray-200: #C1C9D2;
  --gray-300: #A3ACB9;
  --gray-400: #8792A2;
  --gray-500: #697386;
  --gray-600: #505967;
  --gray-700: #3C4257;
  --gray-800: #2A2F45;
  --gray-900: #1A1F36;

  /* Gradient Colors */
  --gradient-color-1: #7038FF;
  --gradient-color-2: #00D4FF;
  --gradient-color-3: #FF57B2;
  --gradient-color-4: #FFBB00;

  /* UI Colors */
  --border-light: #E6E6E6;
  --border-dark: rgba(255,255,255,0.1);
  --hover-light: rgba(10,37,64,0.04);
  --hover-dark: rgba(255,255,255,0.05);

  /* Status Colors */
  --success: #00D924;
  --warning: #FFBB00;
  --error: #ED5F74;

  /* Shadows */
  --shadow-1: 0 2px 5px rgba(50, 50, 93, 0.09), 0 1px 2px rgba(0, 0, 0, 0.07);
  --shadow-2: 0 4px 6px rgba(50, 50, 93, 0.09), 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-3: 0 1px 5px rgba(0, 0, 0, 0.07), 0 7px 17px rgba(0, 0, 0, 0.1);
  --shadow-4: 0 15px 35px rgba(50, 50, 93, 0.1), 0 5px 15px rgba(0, 0, 0, 0.07);
  --shadow-5: 0 15px 35px rgba(50, 50, 93, 0.15), 0 5px 15px rgba(0, 0, 0, 0.1);
  --shadow-float: 0 50px 100px -20px rgba(50, 50, 93, 0.25), 0 30px 60px -30px rgba(0, 0, 0, 0.3);
  --shadow-purple: 0 4px 6px rgba(99, 91, 255, 0.25), 0 1px 3px rgba(0, 0, 0, 0.08);

  /* Spacing */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;
  --space-9: 96px;
  --space-10: 128px;

  /* Border Radius */
  --radius: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-base: 0.25s ease;
  --transition-slow: 0.4s ease;

  /* Container */
  --container-width: 1080px;
  --container-wide: 1280px;
  --container-narrow: 720px;
}

/* === Reset & Base === */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-white);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
}

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

a {
  color: inherit;
  text-decoration: none;
}

button {
  font-family: inherit;
  font-size: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

::selection {
  background: rgba(99, 91, 255, 0.2);
  color: var(--text-primary);
}

:focus-visible {
  outline: 2px solid var(--stripe-purple);
  outline-offset: 2px;
}

/* === Typography === */
h1 {
  font-size: clamp(40px, 6vw, 94px);
  font-weight: 700;
  line-height: 1.06;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

h2 {
  font-size: clamp(28px, 4vw, 52px);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.015em;
  color: var(--text-primary);
}

h3 {
  font-size: 24px;
  font-weight: 600;
  line-height: 1.3;
  color: var(--text-primary);
}

h4 {
  font-size: 20px;
  font-weight: 600;
  line-height: 1.4;
  color: var(--text-primary);
}

.caption {
  font-size: 13px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-tertiary);
}

/* === Navigation === */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--gray-100);
}

.nav-inner {
  max-width: var(--container-wide);
  margin: 0 auto;
  padding: 0 var(--space-5);
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-left {
  display: flex;
  align-items: center;
  gap: var(--space-7);
}

.nav-brand a {
  font-size: 18px;
  font-weight: 700;
  color: var(--stripe-blue);
  letter-spacing: -0.5px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-links a {
  font-size: 15px;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 8px 14px;
  border-radius: var(--radius);
  transition: var(--transition-fast);
}

.nav-links a:hover {
  color: var(--text-primary);
  background: var(--hover-light);
}

.nav-links a.active {
  color: var(--stripe-purple);
  background: rgba(99, 91, 255, 0.08);
}

.nav-right {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-shrink: 0;
}

.hamburger {
  display: none;
  cursor: pointer;
  font-size: 24px;
  padding: 8px;
  color: var(--text-secondary);
  border-radius: var(--radius);
}

.hamburger:hover {
  background: var(--hover-light);
}

.mobile-menu {
  display: none;
  position: absolute;
  top: 64px;
  left: 0;
  right: 0;
  background: var(--bg-white);
  border-bottom: 1px solid var(--gray-100);
  padding: var(--space-3);
  box-shadow: var(--shadow-2);
}

.mobile-menu.show {
  display: block;
}

.mobile-menu a {
  display: block;
  padding: 14px 16px;
  font-size: 15px;
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: var(--radius);
  transition: var(--transition-fast);
}

.mobile-menu a:hover,
.mobile-menu a.active {
  color: var(--text-primary);
  background: var(--hover-light);
}

/* === Buttons === */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 18px;
  font-size: 15px;
  font-weight: 600;
  line-height: 1;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn-primary {
  background: var(--stripe-purple);
  color: white;
  box-shadow: var(--shadow-1);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 7px 14px rgba(50, 50, 93, 0.1), 0 3px 6px rgba(0, 0, 0, 0.08);
  filter: brightness(1.1);
}

.btn-primary:active {
  transform: translateY(1px);
  box-shadow: 0 2px 4px rgba(50, 50, 93, 0.1), 0 1px 2px rgba(0, 0, 0, 0.06);
}

.btn-secondary {
  background: var(--bg-white);
  color: var(--text-primary);
  border: 1px solid var(--gray-200);
  box-shadow: var(--shadow-1);
}

.btn-secondary:hover {
  background: var(--gray-50);
  border-color: var(--gray-300);
  transform: translateY(-1px);
}

.btn-ghost {
  background: transparent;
  color: var(--stripe-purple);
  padding: 12px 14px;
}

.btn-ghost:hover {
  background: rgba(99, 91, 255, 0.08);
}

.btn-arrow::after {
  content: '\2192';
  margin-left: 8px;
  transition: transform var(--transition-fast);
}

.btn-arrow:hover::after {
  transform: translateX(4px);
}

.btn-sm {
  padding: 8px 14px;
  font-size: 14px;
}

.btn-lg {
  padding: 16px 24px;
  font-size: 16px;
}

/* Login/User buttons */
.login-btn {
  background: var(--stripe-purple);
  color: white;
  padding: 8px 16px;
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 600;
  transition: var(--transition-fast);
}

.login-btn:hover {
  filter: brightness(1.1);
  transform: translateY(-1px);
}

.user-btn {
  background: rgba(0, 217, 36, 0.1);
  color: var(--accent-green);
  padding: 8px 16px;
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 600;
  transition: var(--transition-fast);
}

.user-btn:hover {
  background: rgba(0, 217, 36, 0.15);
}

/* Theme toggle */
.theme-toggle {
  background: transparent;
  border: none;
  font-size: 18px;
  cursor: pointer;
  padding: 8px;
  border-radius: var(--radius);
  transition: var(--transition-fast);
}

.theme-toggle:hover {
  background: var(--hover-light);
}

/* === Cards === */
.card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-2);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-4);
}

.card-bordered {
  box-shadow: none;
  border: 1px solid var(--gray-100);
}

.card-bordered:hover {
  border-color: var(--gray-200);
  box-shadow: var(--shadow-2);
}

/* === Container === */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--space-5);
}

.container-wide {
  max-width: var(--container-wide);
}

.container-narrow {
  max-width: var(--container-narrow);
}

/* === Sections === */
.section {
  padding: var(--space-9) 0;
}

.section-sm {
  padding: var(--space-7) 0;
}

.section-lg {
  padding: var(--space-10) 0;
}

.section-dark {
  background: var(--bg-dark);
  color: var(--text-on-dark);
}

.section-light {
  background: var(--bg-light);
}

/* === Content Pages (About, etc.) === */
.page-container {
  max-width: var(--container-narrow);
  margin: 0 auto;
  padding: var(--space-7) var(--space-5);
}

.page-hero {
  text-align: center;
  margin-bottom: var(--space-8);
}

.page-hero h1 {
  font-size: clamp(32px, 5vw, 48px);
  margin-bottom: var(--space-4);
}

.page-hero p {
  font-size: 20px;
  color: var(--text-secondary);
}

.content-section {
  background: var(--bg-white);
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  margin-bottom: var(--space-5);
}

.content-section h2 {
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  margin-bottom: var(--space-5);
  padding-bottom: var(--space-4);
  border-bottom: 1px solid var(--gray-100);
}

.content-section p {
  color: var(--text-secondary);
  margin-bottom: var(--space-4);
  font-size: 16px;
  line-height: 1.7;
}

.content-section p:last-child {
  margin-bottom: 0;
}

.content-section ul {
  color: var(--text-secondary);
  margin-left: var(--space-5);
  font-size: 16px;
  line-height: 1.7;
}

.content-section li {
  margin-bottom: var(--space-2);
}

.content-section a {
  color: var(--stripe-purple);
  font-weight: 500;
}

.content-section a:hover {
  text-decoration: underline;
}

/* Grid layouts */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-4);
}

/* Feature/Diff items */
.feature-item, .diff-item {
  background: var(--gray-50);
  padding: var(--space-5);
  border-radius: var(--radius-lg);
  border: 1px solid var(--gray-100);
  transition: var(--transition-fast);
}

.feature-item:hover, .diff-item:hover {
  border-color: var(--gray-200);
  transform: translateY(-2px);
}

.feature-item h3, .diff-item h3 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-2);
}

.feature-item p, .diff-item p {
  font-size: 14px;
  color: var(--text-tertiary);
  line-height: 1.6;
  margin: 0;
}

/* Timeline */
.timeline {
  margin: var(--space-5) 0;
}

.timeline-item {
  display: flex;
  gap: var(--space-5);
  margin-bottom: var(--space-5);
}

.timeline-marker {
  width: 36px;
  height: 36px;
  background: var(--stripe-purple);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 14px;
  flex-shrink: 0;
}

.timeline-content h3 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-2);
}

.timeline-content p {
  font-size: 15px;
  color: var(--text-tertiary);
  line-height: 1.6;
  margin: 0;
}

/* FAQ */
.faq {
  margin-top: var(--space-4);
}

.faq details {
  background: var(--gray-50);
  border: 1px solid var(--gray-100);
  border-radius: var(--radius);
  margin-bottom: var(--space-2);
  transition: var(--transition-fast);
}

.faq details:hover {
  border-color: var(--gray-200);
}

.faq summary {
  padding: var(--space-4);
  cursor: pointer;
  font-size: 15px;
  font-weight: 600;
  color: var(--text-primary);
  list-style: none;
}

.faq summary::-webkit-details-marker {
  display: none;
}

.faq summary::after {
  content: '+';
  float: right;
  font-size: 18px;
  color: var(--text-tertiary);
  transition: var(--transition-fast);
}

.faq details[open] summary::after {
  content: '\2212';
}

.faq details[open] summary {
  border-bottom: 1px solid var(--gray-100);
}

.faq details p {
  padding: var(--space-4);
  margin: 0;
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* Question list */
.question-list {
  list-style: decimal;
  padding-left: var(--space-5);
  color: var(--text-secondary);
  font-size: 15px;
}

.question-list li {
  padding: var(--space-2) 0;
}

/* Founder profile */
.founder-profile {
  background: var(--gray-50);
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  margin-bottom: var(--space-4);
}

.founder-profile h3 {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-4);
}

.founder-profile ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.founder-profile li {
  font-size: 14px;
  color: var(--text-secondary);
  padding: var(--space-2) 0;
  border-bottom: 1px solid var(--gray-100);
}

.founder-profile li:last-child {
  border-bottom: none;
}

.founder-profile.red {
  border-color: rgba(237, 95, 116, 0.3);
}

.founder-profile.red h3 {
  color: var(--accent-red);
}

/* Build badges */
.build-types {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-4);
}

.build-badge {
  background: rgba(99, 91, 255, 0.1);
  color: var(--stripe-purple);
  padding: 6px 14px;
  border-radius: var(--radius);
  font-size: 13px;
  font-weight: 600;
}

/* Tech stack */
.tech-stack {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.tech-badge {
  background: var(--gray-50);
  padding: 8px 14px;
  border-radius: var(--radius);
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  border: 1px solid var(--gray-100);
}

/* CTA */
.cta {
  text-align: center;
  margin-top: var(--space-7);
}

.cta a {
  display: inline-block;
  padding: 16px 32px;
  background: var(--stripe-purple);
  color: white;
  text-decoration: none;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 16px;
  transition: var(--transition-fast);
  box-shadow: var(--shadow-2);
}

.cta a:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-4);
  filter: brightness(1.1);
}

/* Footer */
.footer {
  text-align: center;
  margin-top: var(--space-8);
  padding: var(--space-5);
  color: var(--text-tertiary);
  font-size: 14px;
}

/* === Expired/Error Pages === */
.page-centered {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.expired-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-7) var(--space-5);
  text-align: center;
}

.expired-icon {
  font-size: 64px;
  margin-bottom: var(--space-6);
  opacity: 0.5;
}

.expired-title {
  font-size: 32px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-4);
}

.expired-message {
  font-size: 17px;
  color: var(--text-secondary);
  max-width: 440px;
  line-height: 1.7;
  margin-bottom: var(--space-6);
}

.expired-actions {
  display: flex;
  gap: var(--space-3);
  flex-wrap: wrap;
  justify-content: center;
}

.expired-note {
  margin-top: var(--space-6);
  font-size: 14px;
  color: var(--text-tertiary);
  max-width: 400px;
}

/* === Animations === */
@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-fade-up {
  animation: fadeUp 0.6s ease forwards;
}

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Staggered animations */
.stagger > *:nth-child(1) { transition-delay: 0ms; }
.stagger > *:nth-child(2) { transition-delay: 100ms; }
.stagger > *:nth-child(3) { transition-delay: 200ms; }
.stagger > *:nth-child(4) { transition-delay: 300ms; }
.stagger > *:nth-child(5) { transition-delay: 400ms; }
.stagger > *:nth-child(6) { transition-delay: 500ms; }

/* === Responsive === */
@media (max-width: 1024px) {
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-inner {
    padding: 0 var(--space-4);
  }

  .nav-links {
    display: none;
  }

  .hamburger {
    display: block;
  }

  .nav-right {
    gap: var(--space-2);
  }

  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }

  .page-container {
    padding: var(--space-6) var(--space-4);
  }

  .content-section {
    padding: var(--space-5);
  }
}

@media (max-width: 480px) {
  .nav-inner {
    padding: 0 var(--space-3);
    height: 56px;
  }

  .nav-right {
    gap: var(--space-1);
  }

  .nav-left {
    gap: var(--space-3);
  }

  .nav-brand a {
    font-size: 16px;
  }

  .theme-toggle {
    padding: 6px;
    font-size: 16px;
  }

  .login-btn, .user-btn {
    padding: 6px 10px;
    font-size: 12px;
  }
}

@media (max-width: 640px) {
  body {
    font-size: 16px;
  }

  .container {
    padding: 0 var(--space-4);
  }

  .btn {
    padding: 14px 20px;
  }

  .timeline-item {
    gap: var(--space-4);
  }

  .timeline-marker {
    width: 32px;
    height: 32px;
    font-size: 13px;
  }
}

/* === Dark Mode === */
body.dark-mode {
  background: var(--bg-dark);
  color: var(--text-on-dark);
}

body.dark-mode h1, body.dark-mode h2, body.dark-mode h3, body.dark-mode h4 {
  color: var(--text-on-dark);
}

body.dark-mode nav {
  background: rgba(10, 37, 64, 0.95);
  border-bottom-color: var(--border-dark);
}

body.dark-mode .nav-links a {
  color: var(--text-on-dark-muted);
}

body.dark-mode .nav-links a:hover {
  color: var(--text-on-dark);
  background: var(--hover-dark);
}

body.dark-mode .nav-links a.active {
  color: var(--stripe-cyan);
  background: rgba(0, 212, 255, 0.1);
}

body.dark-mode .hamburger {
  color: var(--text-on-dark-muted);
}

body.dark-mode .hamburger:hover {
  background: var(--hover-dark);
}

body.dark-mode .mobile-menu {
  background: var(--bg-dark);
  border-bottom-color: var(--border-dark);
}

body.dark-mode .mobile-menu a {
  color: var(--text-on-dark-muted);
}

body.dark-mode .mobile-menu a:hover, body.dark-mode .mobile-menu a.active {
  color: var(--text-on-dark);
  background: var(--hover-dark);
}

body.dark-mode .theme-toggle:hover {
  background: var(--hover-dark);
}

body.dark-mode .card, body.dark-mode .content-section {
  background: var(--gray-900);
  border-color: var(--border-dark);
}

body.dark-mode .content-section h2 {
  color: var(--text-on-dark-muted);
  border-bottom-color: var(--border-dark);
}

body.dark-mode .content-section p, body.dark-mode .content-section ul {
  color: var(--text-on-dark-muted);
}

body.dark-mode .feature-item, body.dark-mode .diff-item, body.dark-mode .founder-profile {
  background: var(--gray-800);
  border-color: var(--border-dark);
}

body.dark-mode .feature-item h3, body.dark-mode .diff-item h3 {
  color: var(--text-on-dark);
}

body.dark-mode .feature-item p, body.dark-mode .diff-item p {
  color: var(--text-on-dark-muted);
}

body.dark-mode .faq details {
  background: var(--gray-800);
  border-color: var(--border-dark);
}

body.dark-mode .faq summary {
  color: var(--text-on-dark);
}

body.dark-mode .faq details p {
  color: var(--text-on-dark-muted);
}

body.dark-mode .faq details[open] summary {
  border-bottom-color: var(--border-dark);
}

body.dark-mode .timeline-content h3 {
  color: var(--text-on-dark);
}

body.dark-mode .timeline-content p {
  color: var(--text-on-dark-muted);
}

body.dark-mode .founder-profile h3 {
  color: var(--text-on-dark);
}

body.dark-mode .founder-profile li {
  color: var(--text-on-dark-muted);
  border-bottom-color: var(--border-dark);
}

body.dark-mode .expired-title {
  color: var(--text-on-dark);
}

body.dark-mode .expired-message {
  color: var(--text-on-dark-muted);
}

body.dark-mode .btn-secondary {
  background: var(--gray-800);
  color: var(--text-on-dark);
  border-color: var(--border-dark);
}

body.dark-mode .btn-secondary:hover {
  background: var(--gray-700);
}

body.dark-mode .footer {
  color: var(--text-on-dark-muted);
}

body.dark-mode ::selection {
  background: rgba(0, 212, 255, 0.3);
  color: var(--text-on-dark);
}