/* ═══════════════════════════════════════════════════════════════
   EduStack Marketing — Stripe Design System
   Inspired by Stripe.com (Light, Vibrant, Precise)
   ═══════════════════════════════════════════════════════════════ */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600&display=swap');

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

:root {
  /* Core Palette */
  --color-primary: #533afd;
  --color-primary-hover: #665efd;
  
  --color-bg: #ffffff;
  --color-surface: #f8fafd;
  --color-surface-accent: #e5edf5;
  
  --text-primary: #061b31;
  --text-body: #000000;
  --text-muted: #50617a;
  --text-inverse: #ffffff;
  
  --border: #e5edf5;
  
  --accent-green: #15be53;
  --accent-orange: #ff6118;
  --accent-pink: #ffe0ef;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  
  /* Radius & Spacing */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 16px;
  --radius-full: 100px;
  
  /* Elevation */
  --shadow-card: rgba(23, 23, 23, 0.06) 0px 3px 6px 0px;
  --shadow-hover: rgba(23, 23, 23, 0.08) 0px 15px 35px 0px;
  --shadow-focus: rgba(99, 91, 255, 0.1) 0px 0px 0px 3px;
}

html { 
  font-family: var(--font-sans); 
  background: var(--color-bg); 
  color: var(--text-body); 
  scroll-behavior: smooth; 
  -webkit-font-smoothing: antialiased; 
}
body { overflow-x: hidden; line-height: 1.4; }
a { color: inherit; text-decoration: none; transition: all 0.2s ease; }
img { max-width: 100%; display: block; }
ul { list-style: none; }

/* ─── Animations ─── */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes gradientFlow {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}
.animate-fade-in-up {
  animation: fadeInUp 0.8s cubic-bezier(0.16, 1, 0.3, 1) forwards;
  opacity: 0;
}
.delay-100 { animation-delay: 100ms; }
.delay-200 { animation-delay: 200ms; }
.delay-300 { animation-delay: 300ms; }

/* ─── Typography ─── */
.display-title {
  font-size: clamp(40px, 5vw, 48px);
  font-weight: 300;
  line-height: 1.03;
  letter-spacing: -0.01em;
  color: var(--text-primary);
}
.section-title {
  font-size: clamp(28px, 4vw, 32px);
  font-weight: 400;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--text-primary);
  margin-bottom: 16px;
}
.card-title {
  font-size: 22px;
  font-weight: 400;
  line-height: 1.3;
  color: var(--text-primary);
  margin-bottom: 8px;
}
.body-text {
  font-size: 16px;
  font-weight: 400;
  line-height: 1.4;
  color: var(--text-muted);
}
.caption {
  font-size: 14px;
  color: var(--text-muted);
}

/* ─── Layout & Containers ─── */
.container { 
  max-width: 1280px; 
  margin: 0 auto; 
  width: 100%; 
  padding: 0 32px; 
}
section { padding: 96px 0; }
section.bg-surface { background: var(--color-surface); }

/* ─── Navigation ─── */
.nav-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 99;
  width: 100%;
  padding: 16px 32px;
  background-color: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-logo {
  display: flex; align-items: center; gap: 8px;
  font-size: 22px; font-weight: 500; color: var(--text-primary);
  letter-spacing: -0.01em;
}
.nav-links { display: flex; align-items: center; gap: 4px; }
.nav-links a { 
  font-size: 14px; 
  font-weight: 500;
  color: var(--text-primary); 
  padding: 8px 16px;
  border-radius: var(--radius-full);
  transition: color 0.2s ease, background-color 0.2s ease;
}
.nav-links a:hover { color: var(--color-primary); background-color: var(--color-surface); }
.nav-cta { display: flex; align-items: center; gap: 12px; }

/* ─── Buttons ─── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 20px;
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 1;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.2s ease-out;
}
.btn-primary {
  background-color: var(--color-primary);
  color: var(--text-inverse);
  padding: 16px 24px;
}
.btn-primary:hover { 
  background-color: var(--color-primary-hover); 
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(83, 58, 253, 0.25);
}
.btn-primary:active { transform: translateY(0); }

.btn-secondary {
  background-color: transparent;
  color: var(--color-primary);
  font-size: 14px;
  border: 1px solid var(--border);
}
.btn-secondary:hover {
  background-color: rgba(83, 58, 253, 0.05);
  border-color: rgba(83, 58, 253, 0.3);
}

.btn-ghost {
  background-color: transparent;
  color: var(--text-primary);
  font-size: 14px;
}
.btn-ghost:hover {
  color: var(--color-primary);
  background-color: var(--color-surface);
}

/* ─── Hero Section ─── */
.hero-wrapper {
  position: relative;
  overflow: hidden;
  padding: 120px 0 80px;
}
/* The signature Stripe flowing gradient */
.hero-gradient {
  position: absolute;
  top: -50%; left: -50%; right: -50%; bottom: -20%;
  background: linear-gradient(-45deg, #ff6118, #ffe0ef, #533afd, #fff);
  background-size: 400% 400%;
  animation: gradientFlow 15s ease infinite;
  transform: skewY(-10deg);
  transform-origin: top left;
  z-index: -1;
  opacity: 0.15;
  filter: blur(60px);
}
.hero-content {
  max-width: 800px;
  position: relative;
  z-index: 1;
}
.hero-actions {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 32px;
}

/* ─── Cards ─── */
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 32px; }

.card {
  background-color: var(--color-bg);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-card);
  transition: box-shadow 0.25s ease-out, transform 0.25s ease-out;
  border: 1px solid rgba(229, 237, 245, 0.5);
}
.card:hover { 
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}
.card-icon {
  width: 40px; height: 40px;
  margin-bottom: 24px;
  color: var(--color-primary);
}
.card-icon svg { width: 100%; height: 100%; }

/* ─── Inputs ─── */
.form-input {
  width: 100%;
  padding: 12px 16px;
  background-color: var(--color-bg);
  color: var(--text-body);
  font-family: var(--font-sans);
  font-size: 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: all 0.2s ease-out;
}
.form-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: var(--shadow-focus);
}

/* ─── Standard Link ─── */
.link {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: 500;
}
.link:hover { text-decoration: underline; }

/* ─── Footer ─── */
.footer {
  padding: 80px 32px 32px;
  background-color: var(--color-surface);
  border-top: 1px solid var(--border);
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: 48px;
  max-width: 1280px;
  margin: 0 auto;
}
.footer-col h4 {
  color: var(--text-primary);
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 16px;
}
.footer-link {
  display: block;
  color: var(--text-muted);
  font-size: 14px;
  padding: 6px 0;
}
.footer-link:hover { color: var(--color-primary); }
.footer-bottom {
  max-width: 1280px;
  margin: 64px auto 0;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  display: flex; justify-content: space-between;
  color: var(--text-muted);
  font-size: 14px;
}

/* ─── Utilities ─── */
.text-center { text-align: center; }
.text-accent { color: var(--color-primary); }
.mt-8 { margin-top: 8px; } .mt-16 { margin-top: 16px; } .mt-24 { margin-top: 24px; }
.mt-32 { margin-top: 32px; } .mt-48 { margin-top: 48px; } .mt-64 { margin-top: 64px; }
.mb-24 { margin-bottom: 24px; } .mb-48 { margin-bottom: 48px; }

/* ─── Responsive ─── */
.nav-toggle { display: none; background: none; border: none; color: var(--text-primary); cursor: pointer; }

@media (max-width: 640px) {
  .container { padding: 0 24px; }
  .nav-bar { padding: 12px 24px; }
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .nav-links { display: none; }
  .nav-toggle { display: block; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-bottom { flex-direction: column; gap: 16px; }
  section { padding: 64px 0; }
  .hero-wrapper { padding: 80px 0 40px; }
}

/* Additional Component Styles */
.plan-name { font-size: 24px; font-weight: 500; color: var(--text-primary); margin-bottom: 8px; }
.plan-desc { font-size: 14px; color: var(--text-muted); margin-bottom: 24px; min-height: 40px; }
.price { font-size: 48px; font-weight: 300; color: var(--text-primary); margin-bottom: 8px; letter-spacing: -0.02em; }
.price-note { font-size: 14px; color: var(--text-muted); margin-bottom: 24px; }
.divider { height: 1px; background-color: var(--border); margin: 24px 0; }
.card ul { margin-bottom: 32px; }
.card li { display: flex; align-items: flex-start; gap: 8px; margin-bottom: 12px; font-size: 14px; color: var(--text-muted); }
.check { color: var(--color-primary); font-weight: bold; }
.module-category { margin-bottom: 48px; }
.module-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 16px; }
.module-card { display: flex; align-items: center; gap: 12px; padding: 16px; background: var(--color-surface); border-radius: var(--radius-md); border: 1px solid var(--border); }
.module-icon { width: 24px; height: 24px; color: var(--color-primary); }

/* Form specific styles */
.form-group { margin-bottom: 24px; }
.form-label { display: block; margin-bottom: 8px; font-size: 14px; font-weight: 500; color: var(--text-primary); }
.form-textarea { width: 100%; padding: 12px 16px; background-color: var(--color-bg); color: var(--text-body); font-family: var(--font-sans); font-size: 16px; border: 1px solid var(--border); border-radius: var(--radius-sm); transition: all 0.2s ease-out; min-height: 120px; resize: vertical; }
.form-textarea:focus { outline: none; border-color: var(--color-primary); box-shadow: var(--shadow-focus); }
.form-select { width: 100%; padding: 12px 16px; background-color: var(--color-bg); color: var(--text-body); font-family: var(--font-sans); font-size: 16px; border: 1px solid var(--border); border-radius: var(--radius-sm); transition: all 0.2s ease-out; appearance: none; }
.form-select:focus { outline: none; border-color: var(--color-primary); box-shadow: var(--shadow-focus); }

/* 3D Isometric Hero Visual */
.hero-wrapper {
  perspective: 1000px;
  overflow: visible;
}
.hero-visual-container {
  display: flex;
  justify-content: center;
  align-items: center;
  margin-top: 64px;
  transform-style: preserve-3d;
  animation: float-3d 6s ease-in-out infinite;
}
.isometric-card {
  width: 600px;
  height: 350px;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(20px);
  border-radius: 16px;
  border: 1px solid rgba(255, 255, 255, 0.5);
  box-shadow: 
    -20px 20px 60px rgba(83, 58, 253, 0.15),
    0 0 0 1px rgba(255, 255, 255, 0.8) inset;
  transform: rotateX(25deg) rotateY(-15deg) rotateZ(5deg);
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}
.isometric-header {
  height: 48px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  padding: 0 16px;
  gap: 8px;
}
.iso-dot { width: 10px; height: 10px; border-radius: 50%; background: #e5edf5; }
.iso-dot:nth-child(1) { background: #ff6118; }
.iso-dot:nth-child(2) { background: #fdbf2d; }
.iso-dot:nth-child(3) { background: #15be53; }

.isometric-body {
  flex: 1;
  padding: 24px;
  display: flex;
  gap: 16px;
}
.iso-sidebar {
  width: 120px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.iso-line { height: 12px; background: var(--border); border-radius: 4px; }
.iso-line.primary { background: rgba(83, 58, 253, 0.2); }
.iso-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.iso-chart {
  height: 120px;
  background: linear-gradient(180deg, rgba(83, 58, 253, 0.1) 0%, rgba(83, 58, 253, 0) 100%);
  border-radius: 8px;
  border-bottom: 2px solid var(--color-primary);
  position: relative;
}
.iso-chart::after {
  content: ''; position: absolute; bottom: 0; left: 10%; width: 80%; height: 60%;
  background: var(--color-primary); clip-path: polygon(0 100%, 20% 40%, 40% 60%, 60% 20%, 80% 50%, 100% 10%, 100% 100%);
  opacity: 0.8;
}
.iso-cards {
  display: flex;
  gap: 12px;
}
.iso-minicard {
  flex: 1;
  height: 60px;
  background: var(--surface-accent);
  border-radius: 6px;
}

@keyframes float-3d {
  0% { transform: translateY(0px) rotateX(0deg); }
  50% { transform: translateY(-15px) rotateX(2deg); }
  100% { transform: translateY(0px) rotateX(0deg); }
}

/* 3D Tilt Cards Hover */
.tilt-card {
  transition: transform 0.1s ease-out;
  transform-style: preserve-3d;
  will-change: transform;
}
.tilt-card:hover {
  box-shadow: rgba(83, 58, 253, 0.2) 0px 20px 40px -10px;
}
.tilt-content {
  transform: translateZ(30px); /* Pushes content towards viewer during tilt */
}