/* ==========================================================================
   Qixev Design System & Global Styles
   Aesthetic: Dark modern engineering, clean typography, calm tonal surfaces
   ========================================================================== */

:root {
  --bg-primary: #0b0d11;
  --bg-secondary: #12151c;
  --bg-tertiary: #191d26;
  --bg-card: #151821;
  --bg-card-hover: #1b202c;

  --border-subtle: #242936;
  --border-strong: #333a4d;
  --border-focus: #3b82f6;

  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;

  --accent-primary: #3b82f6;
  --accent-hover: #60a5fa;
  --accent-subtle: rgba(59, 130, 246, 0.12);

  --status-warning-bg: rgba(234, 179, 8, 0.1);
  --status-warning-border: rgba(234, 179, 8, 0.3);
  --status-warning-text: #fde047;

  --status-info-bg: rgba(59, 130, 246, 0.1);
  --status-info-border: rgba(59, 130, 246, 0.25);
  --status-info-text: #93c5fd;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

  --container-max-width: 1080px;
  --container-padding: 1.5rem;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
}

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

html {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Skip Navigation Link for Accessibility */
.skip-link {
  position: absolute;
  top: -999px;
  left: 1rem;
  background: var(--accent-primary);
  color: #fff;
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-sm);
  z-index: 9999;
  text-decoration: none;
  font-weight: 600;
}

.skip-link:focus {
  top: 1rem;
}

/* Typography */
h1, h2, h3, h4 {
  color: var(--text-primary);
  line-height: 1.25;
  font-weight: 600;
  letter-spacing: -0.02em;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

h2 {
  font-size: 1.75rem;
  margin-bottom: 0.85rem;
}

h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

p {
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
  font-size: 1rem;
}

p.lead {
  font-size: 1.15rem;
  color: var(--text-primary);
}

a {
  color: var(--accent-hover);
  text-decoration: none;
  transition: color 0.15s ease;
}

a:hover {
  color: #fff;
  text-decoration: underline;
}

a:focus-visible, button:focus-visible, input:focus-visible {
  outline: 2px solid var(--border-focus);
  outline-offset: 3px;
}

/* Layout Container */
.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

/* Site Header & Navigation */
.site-header {
  border-bottom: 1px solid var(--border-subtle);
  background-color: rgba(11, 13, 17, 0.85);
  backdrop-filter: blur(12px);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--text-primary);
  text-decoration: none;
}

.brand:hover {
  text-decoration: none;
}

.brand-icon {
  width: 24px;
  height: 24px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.75rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
  text-decoration: none;
}

.menu-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.9rem;
}

/* Main Content Area */
main {
  flex: 1;
  padding-top: 2rem;
  padding-bottom: 4rem;
}

/* Hero Section */
.hero {
  padding: 4rem 0 3.5rem;
  border-bottom: 1px solid var(--border-subtle);
}

.hero-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent-hover);
  background-color: var(--accent-subtle);
  border: 1px solid rgba(59, 130, 246, 0.25);
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-sm);
  margin-bottom: 1.25rem;
}

.hero-title {
  font-size: 3rem;
  letter-spacing: -0.03em;
  margin-bottom: 1rem;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 680px;
  line-height: 1.5;
  margin-bottom: 2rem;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.65rem 1.25rem;
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.15s ease;
  text-decoration: none;
}

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

.btn-primary:hover {
  background-color: var(--accent-hover);
  color: #fff;
  text-decoration: none;
}

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

.btn-secondary:hover {
  background-color: var(--bg-tertiary);
  border-color: var(--border-strong);
  color: var(--text-primary);
  text-decoration: none;
}

/* Cards & Grid Layouts */
.grid {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  margin: 2rem 0;
}

.card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  transition: border-color 0.15s ease, background-color 0.15s ease;
}

.card:hover {
  border-color: var(--border-strong);
  background-color: var(--bg-card-hover);
}

.card-title {
  margin-bottom: 0.5rem;
}

.card-text {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

/* Notice & Status Banners */
.notice {
  padding: 1rem 1.25rem;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  margin: 1.5rem 0;
  line-height: 1.5;
}

.notice-warning {
  background-color: var(--status-warning-bg);
  border: 1px solid var(--status-warning-border);
  color: var(--status-warning-text);
}

.notice-info {
  background-color: var(--status-info-bg);
  border: 1px solid var(--status-info-border);
  color: var(--status-info-text);
}

.hidden {
  display: none !important;
}

/* Support Page Specifics */
.tier-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  margin: 1.5rem 0;
}

.tier-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  text-align: center;
}

.tier-amount {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.tier-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1.25rem;
}

.tier-button.disabled,
.btn.disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: auto;
}

.custom-support-form {
  display: flex;
  gap: 0.75rem;
  max-width: 420px;
  margin: 1rem 0;
}

.custom-input {
  flex: 1;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  padding: 0.65rem 0.85rem;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
}

.custom-input:focus {
  border-color: var(--border-focus);
}

/* Non-Financial Support List */
.support-action-list {
  list-style: none;
  margin: 1.5rem 0;
}

.support-action-item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--border-subtle);
}

.support-action-item:last-child {
  border-bottom: none;
}

.action-icon {
  font-size: 1.25rem;
}

.action-title {
  font-weight: 600;
  color: var(--text-primary);
}

.action-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* Documentation Content (Privacy, License) */
.legal-content {
  max-width: 760px;
  margin: 2rem 0;
}

.legal-content h2 {
  margin-top: 2rem;
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 0.5rem;
}

.legal-content ul {
  margin-left: 1.5rem;
  margin-bottom: 1.5rem;
  color: var(--text-secondary);
}

.legal-content li {
  margin-bottom: 0.5rem;
}

code {
  font-family: var(--font-mono);
  background-color: var(--bg-tertiary);
  padding: 0.2rem 0.4rem;
  border-radius: 3px;
  font-size: 0.85em;
  color: #e2e8f0;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border-subtle);
  padding: 2.5rem 0;
  background-color: var(--bg-secondary);
  font-size: 0.9rem;
  color: var(--text-muted);
}

.footer-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-nav {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}

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

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

/* Media Queries for Mobile Responsiveness */
@media (max-width: 768px) {
  .hero-title {
    font-size: 2.25rem;
  }

  .menu-toggle {
    display: block;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 4rem;
    left: 0;
    right: 0;
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-subtle);
    flex-direction: column;
    padding: 1.5rem;
    gap: 1.25rem;
  }

  .nav-links.active {
    display: flex;
  }

  .custom-support-form {
    flex-direction: column;
  }

  .footer-container {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* Reduced Motion Preference */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}