/* 
  Cloud L2 - Premium UI Stylesheet
  Inspired by modern, sleek interfaces with a focus on typography and spacing.
  Font: macOS native system fonts for a smooth, humanized reading experience.
*/

:root {
  --bg-primary: #FAF8F5; /* Warm off-white, similar to Claude */
  --bg-secondary: #FFFFFF;
  --text-primary: #2D2D2D;
  --text-secondary: #5F5F5F;
  --accent-color: #D36C4F; /* Soft, premium orange/rust accent */
  --accent-hover: #C25B3E;
  --border-color: #E6E2DB;
  --ad-bg: #F0EEEA;
  
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
  
  --transition-fast: 0.2s ease;
  --transition-smooth: 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.04);
  --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
  --shadow-lg: 0 24px 48px rgba(0,0,0,0.12);
}

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

body {
  font-family: var(--font-main);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ==========================================================================
   Typography
   ========================================================================== */
h1, h2, h3, h4, h5, h6 {
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

h1 { font-size: 3.5rem; margin-bottom: 1rem; }
h2 { font-size: 2.5rem; margin-bottom: 1rem; }
p { font-size: 1.125rem; color: var(--text-secondary); margin-bottom: 1.5rem; }
a { color: var(--text-primary); text-decoration: none; transition: color var(--transition-fast); }
a:hover { color: var(--accent-color); }

/* ==========================================================================
   Navigation
   ========================================================================== */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.5rem 4rem;
  background-color: var(--bg-primary);
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid transparent;
  transition: border-bottom var(--transition-fast), background-color var(--transition-fast);
}

.navbar.scrolled {
  background-color: rgba(250, 248, 245, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.nav-logo {
  height: 32px;
  width: 32px;
  border-radius: 50%;
  object-fit: cover;
}

.nav-links {
  display: flex;
  gap: 2.5rem;
  align-items: center;
}

.nav-link {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  width: 0;
  height: 2px;
  bottom: -4px;
  left: 0;
  background-color: var(--accent-color);
  transition: width var(--transition-smooth);
}

.nav-link:hover {
  color: var(--text-primary);
}

.nav-link:hover::after, .nav-link.active::after {
  width: 100%;
}

.nav-link.active {
  color: var(--text-primary);
}

/* ==========================================================================
   Buttons
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  font-weight: 500;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  border: none;
  font-family: var(--font-main);
}

.btn-primary {
  background-color: var(--accent-color);
  color: #FFFFFF;
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  transform: translateY(-1px);
  color: #FFFFFF;
  box-shadow: var(--shadow-md);
}

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

.btn-secondary:hover {
  border-color: var(--text-primary);
}

/* ==========================================================================
   Main Layout & Sections
   ========================================================================== */
main {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.hero-section {
  padding: 8rem 4rem;
  text-align: center;
  max-width: 900px;
  margin: 0 auto;
  animation: fadeUp 0.8s var(--transition-smooth) forwards;
  opacity: 0;
  transform: translateY(20px);
}

.content-section {
  padding: 4rem;
  max-width: 800px;
  margin: 0 auto;
  width: 100%;
}

/* ==========================================================================
   Forms & Inputs
   ========================================================================== */
.form-group {
  margin-bottom: 1.5rem;
  text-align: left;
}

.form-label {
  display: block;
  font-weight: 500;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.form-input {
  width: 100%;
  padding: 1rem 1.25rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 1rem;
  font-family: var(--font-main);
  background-color: var(--bg-secondary);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-input:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(211, 108, 79, 0.1);
}

/* Trial Flow Container */
.trial-container {
  background-color: var(--bg-secondary);
  padding: 3rem;
  border-radius: 16px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
  margin-top: 2rem;
}

/* Invite Link Display */
.invite-box {
  background-color: var(--bg-primary);
  border: 1px dashed var(--accent-color);
  padding: 2rem;
  border-radius: 8px;
  margin-top: 2rem;
  display: none;
  animation: fadeIn 0.5s ease;
}

.invite-link {
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--accent-color);
  word-break: break-all;
  display: inline-block;
  margin: 1rem 0;
}

/* ==========================================================================
   Popup Modal (Campaign)
   ========================================================================== */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(4px);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-smooth);
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal-content {
  background-color: var(--bg-secondary);
  padding: 3rem;
  border-radius: 20px;
  max-width: 500px;
  width: 90%;
  text-align: center;
  box-shadow: var(--shadow-lg);
  transform: scale(0.95) translateY(10px);
  transition: all var(--transition-smooth);
  position: relative;
}

.modal-overlay.active .modal-content {
  transform: scale(1) translateY(0);
}

.modal-close {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.modal-close:hover {
  color: var(--text-primary);
}

.campaign-badge {
  display: inline-block;
  background-color: rgba(211, 108, 79, 0.1);
  color: var(--accent-color);
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

/* ==========================================================================
   Ad Banner Area
   ========================================================================== */
.ad-banner-container {
  width: 100%;
  max-width: 728px;
  min-height: 90px;
  margin: 2rem auto;
  background-color: var(--ad-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  font-size: 0.875rem;
  text-align: center;
  overflow: hidden;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.footer {
  margin-top: auto;
  padding: 3rem 4rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 2rem;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
}

.footer-link {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.footer-link:hover {
  color: var(--text-primary);
}

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

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (max-width: 768px) {
  .navbar { padding: 1.25rem 1.5rem; }
  .nav-links { display: none; /* In a full app, implement a hamburger menu */ }
  .hero-section { padding: 4rem 1.5rem; }
  h1 { font-size: 2.5rem; }
  .content-section { padding: 2rem 1.5rem; }
  .footer { padding: 2rem 1.5rem; flex-direction: column; text-align: center; }
}