/* ==========================================================================
   Simple PC Monitor - Product Landing Page Stylesheet
   Zero External Dependencies | Clean, Minimalist & Ultra-Fast CSS3
   ========================================================================== */

:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "Cascadia Code", "Consolas", "Courier New", monospace;
  
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-full: 9999px;
  
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.4s cubic-bezier(0.16, 1, 0.3, 1);

  /* Modern Dark Theme */
  --bg-primary: #0f111a;
  --bg-surface: #171926;
  --bg-surface-elevated: #202438;
  --bg-glass: rgba(23, 25, 38, 0.85);
  --border-color: rgba(255, 255, 255, 0.09);
  --border-focus: #38bdf8;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-primary: #38bdf8;
  --accent-secondary: #a78bfa;
  --accent-success: #34d399;
  --accent-warning: #fbbf24;
  --accent-danger: #fb7185;
  --glow-primary: rgba(56, 189, 248, 0.2);
  --glow-accent: rgba(167, 139, 250, 0.2);
  --card-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
}

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

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Typography */
h1, h2, h3, h4 {
  color: var(--text-primary);
  line-height: 1.25;
  font-weight: 700;
}

p {
  color: var(--text-secondary);
}

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

a:hover {
  text-decoration: underline;
}

/* Header & Navigation */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--bg-glass);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-color);
  transition: border-color var(--transition-normal), background-color var(--transition-normal);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  cursor: default;
  user-select: none;
}

.brand-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  filter: drop-shadow(0 2px 8px var(--glow-primary));
}

.brand-text {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.brand-badge {
  font-size: 0.75rem;
  font-weight: 600;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  color: var(--accent-primary);
  padding: 2px 8px;
  border-radius: var(--radius-full);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-link {
  font-size: 0.925rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.nav-link:hover {
  color: var(--text-primary);
  text-decoration: none;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* Clean Language Switcher (Text only) */
.lang-btn {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-weight: 700;
  font-size: 0.85rem;
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  letter-spacing: 0.05em;
  transition: var(--transition-fast);
}

.lang-btn:hover {
  background: var(--bg-surface-elevated);
  border-color: var(--border-focus);
  color: var(--accent-primary);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 600;
  font-size: 0.95rem;
  padding: 10px 22px;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: var(--transition-normal);
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  color: #ffffff;
  box-shadow: 0 4px 20px var(--glow-primary);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px var(--glow-primary);
  text-decoration: none;
  color: #ffffff;
}

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

.btn-secondary:hover {
  background: var(--bg-surface);
  border-color: var(--border-focus);
  transform: translateY(-2px);
  text-decoration: none;
}

.btn-sm {
  padding: 6px 14px;
  font-size: 0.85rem;
}

.btn-lg {
  padding: 14px 28px;
  font-size: 1.05rem;
}

/* Hero Section */
.hero {
  position: relative;
  padding: 90px 0 80px;
  overflow: hidden;
}

.hero-glow {
  position: absolute;
  top: 20%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 700px;
  height: 450px;
  background: radial-gradient(circle, var(--glow-primary) 0%, rgba(0,0,0,0) 70%);
  z-index: -1;
  pointer-events: none;
  filter: blur(80px);
}

.hero-content {
  text-align: center;
  max-width: 860px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  padding: 6px 16px;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  margin-bottom: 24px;
  color: var(--accent-primary);
  box-shadow: 0 4px 12px var(--glow-primary);
}

.hero-title {
  font-size: clamp(2.4rem, 5vw, 3.8rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
  background: linear-gradient(135deg, var(--text-primary) 40%, var(--accent-primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  line-height: 1.6;
  color: var(--text-secondary);
  margin-bottom: 36px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 16px;
  margin-bottom: 36px;
}

.hero-highlights {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 24px;
  font-size: 0.875rem;
  color: var(--text-muted);
}

.highlight-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.highlight-item svg {
  color: var(--accent-success);
}

/* Sections Common */
.section {
  padding: 80px 0;
}

.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 60px;
}

.section-tag {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent-primary);
  margin-bottom: 12px;
  display: inline-block;
}

.section-title {
  font-size: clamp(2rem, 3.5vw, 2.6rem);
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
}

/* Features Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 28px;
}

.feature-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px;
  position: relative;
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
}

.feature-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-focus);
  box-shadow: var(--card-shadow);
}

.feature-icon-box {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 22px;
  color: var(--accent-primary);
  box-shadow: 0 4px 14px var(--glow-primary);
}

.feature-title {
  font-size: 1.25rem;
  margin-bottom: 12px;
}

.feature-text {
  font-size: 0.95rem;
  line-height: 1.6;
}

.feature-badge {
  display: inline-block;
  margin-top: 16px;
  font-size: 0.75rem;
  font-family: var(--font-mono);
  padding: 3px 10px;
  border-radius: var(--radius-full);
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
}

/* Downloads Matrix */
.downloads-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 28px;
  margin-bottom: 50px;
}

.download-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  text-align: center;
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition-normal);
}

.download-card.featured {
  border-color: var(--accent-primary);
  box-shadow: var(--card-shadow);
}

.card-ribbon {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 14px;
  border-radius: var(--radius-full);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.download-type {
  font-size: 1.35rem;
  margin-bottom: 8px;
}

.download-size {
  font-size: 2rem;
  font-weight: 800;
  color: var(--text-primary);
  font-family: var(--font-mono);
  margin: 14px 0 6px;
}

.download-info {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 24px;
  min-height: 48px;
}

.download-specs {
  list-style: none;
  margin-bottom: 28px;
  text-align: left;
  font-size: 0.875rem;
}

.download-specs li {
  padding: 6px 0;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-secondary);
  border-bottom: 1px dashed var(--border-color);
}

.download-specs li svg {
  color: var(--accent-success);
  flex-shrink: 0;
}

/* Specs Table */
.specs-table-wrap {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow-x: auto;
  box-shadow: var(--card-shadow);
}

.specs-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.925rem;
}

.specs-table th, .specs-table td {
  padding: 16px 24px;
  border-bottom: 1px solid var(--border-color);
}

.specs-table th {
  background: var(--bg-surface-elevated);
  font-weight: 700;
  color: var(--text-primary);
}

.specs-table tr:last-child td {
  border-bottom: none;
}

/* Security Guarantee Banner */
.security-banner {
  background: linear-gradient(135deg, var(--bg-surface), var(--bg-surface-elevated));
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px;
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 28px;
  align-items: center;
  margin-top: 40px;
}

.security-icon {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: rgba(52, 211, 153, 0.15);
  border: 1px solid var(--accent-success);
  color: var(--accent-success);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* FAQ Accordion */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition-fast);
}

.faq-question {
  width: 100%;
  text-align: left;
  padding: 18px 22px;
  background: none;
  border: none;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
}

.faq-question svg {
  transition: transform var(--transition-fast);
  color: var(--text-muted);
}

.faq-item.active .faq-question svg {
  transform: rotate(180deg);
  color: var(--accent-primary);
}

.faq-answer {
  padding: 0 22px 18px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  display: none;
}

.faq-item.active .faq-answer {
  display: block;
}

/* Footer */
.site-footer {
  background: var(--bg-surface);
  border-top: 1px solid var(--border-color);
  padding: 50px 0 30px;
  margin-top: 60px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand p {
  margin-top: 12px;
  font-size: 0.9rem;
  max-width: 340px;
}

.footer-col h4 {
  font-size: 0.95rem;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

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

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Responsive */
@media (max-width: 860px) {
  .nav-menu { display: none; }
  .footer-grid { grid-template-columns: 1fr; }
  .security-banner { grid-template-columns: 1fr; text-align: center; }
  .security-icon { margin: 0 auto; }
}

@media (max-width: 600px) {
  .hero-actions { flex-direction: column; width: 100%; }
  .btn-lg { width: 100%; }
  .footer-bottom { flex-direction: column; gap: 12px; text-align: center; }
}