/* ==========================================================================
   SoundPlus — Apple-Inspired Minimalist Design System
   Rules: Zero Emojis, Zero Gradients, Pure Monochrome & Precision Accents
   ========================================================================== */

:root {
  --bg-primary: #000000;
  --bg-surface: #0c0c0e;
  --bg-card: #121215;
  --bg-elevated: #18181c;
  --bg-hover: #1f1f24;

  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-focus: rgba(255, 255, 255, 0.22);
  --border-active: #ffffff;

  --text-primary: #f5f5f7;
  --text-secondary: #86868b;
  --text-tertiary: #515154;
  --text-inverse: #000000;

  --accent-blue: #2997ff;
  --accent-blue-hover: #147ce5;
  --accent-green: #30d158;

  --font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", "Inter", sans-serif;
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-pill: 9999px;

  --transition-fast: 0.15s cubic-bezier(0.2, 0.8, 0.2, 1);
  --transition-smooth: 0.3s cubic-bezier(0.25, 1, 0.5, 1);
  --container-max: 1140px;
}

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

html {
  font-size: 16px;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-family);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

body {
  line-height: 1.5;
  overflow-x: hidden;
  background-color: var(--bg-primary);
}

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

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

/* ==========================================================================
   Typography & Utilities
   ========================================================================== */

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
}

.eyebrow {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent-blue);
  margin-bottom: 12px;
  display: inline-block;
}

.headline-hero {
  font-size: clamp(2.5rem, 6vw, 4.25rem);
  font-weight: 700;
  line-height: 1.06;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  margin-bottom: 20px;
}

.headline-section {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  line-height: 1.12;
  letter-spacing: -0.025em;
  color: var(--text-primary);
  margin-bottom: 16px;
}

.subheadline {
  font-size: clamp(1.05rem, 2vw, 1.35rem);
  font-weight: 400;
  line-height: 1.5;
  color: var(--text-secondary);
  max-width: 680px;
}

.text-center {
  text-align: center;
}

.mx-auto {
  margin-left: auto;
  margin-right: auto;
}

/* ==========================================================================
   Navigation
   ========================================================================== */

.nav-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(0, 0, 0, 0.82);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-subtle);
}

.nav-inner {
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.brand-icon {
  width: 28px;
  height: 28px;
  border-radius: 7px;
  border: 1px solid var(--border-subtle);
}

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

.nav-link {
  font-size: 0.875rem;
  color: var(--text-secondary);
  font-weight: 400;
}

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

.nav-link-web {
  display: none;
}

@media (min-width: 640px) {
  .nav-link-web {
    display: inline-block;
  }
}

.btn-nav {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--text-primary);
  color: var(--text-inverse);
  font-size: 0.8125rem;
  font-weight: 600;
  padding: 8px 16px;
  border-radius: var(--radius-pill);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.btn-nav:hover {
  opacity: 0.9;
  transform: scale(1.02);
}

/* ==========================================================================
   Buttons & CTAs
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-size: 0.95rem;
  font-weight: 600;
  padding: 14px 28px;
  border-radius: var(--radius-pill);
  cursor: pointer;
  transition: all var(--transition-fast);
  border: 1px solid transparent;
}

.btn-primary {
  background: #ffffff;
  color: #000000;
}

.btn-primary:hover {
  background: #e5e5ea;
  transform: translateY(-1px);
}

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

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

.cta-group {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

/* ==========================================================================
   Hero Section
   ========================================================================== */

.hero-section {
  padding: 90px 0 60px;
  text-align: center;
}

.hero-content {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.hero-meta-bar {
  display: flex;
  align-items: center;
  gap: 20px;
  margin-top: 24px;
  font-size: 0.8125rem;
  color: var(--text-secondary);
  flex-wrap: wrap;
  justify-content: center;
}

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

.hero-meta-dot {
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--text-tertiary);
}

/* ==========================================================================
   Phone Mockup Showcase (Apple Minimalist Bezel)
   ========================================================================== */

.mockup-wrapper {
  margin-top: 56px;
  position: relative;
  display: flex;
  justify-content: center;
}

.phone-frame {
  width: 100%;
  max-width: 320px;
  background: #000000;
  border-radius: 46px;
  padding: 11px;
  border: 2px solid #27272a;
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.9), 0 0 0 1px rgba(255, 255, 255, 0.05);
}

.phone-screen {
  width: 100%;
  border-radius: 36px;
  overflow: hidden;
  background: #0a0a0f;
  aspect-ratio: 9 / 19.5;
}

.phone-screen img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

/* ==========================================================================
   App Screenshots Carousel / Grid
   ========================================================================== */

.section-showcase {
  padding: 100px 0;
  border-top: 1px solid var(--border-subtle);
}

.gallery-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-top: 56px;
}

.gallery-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 24px 20px 20px;
  display: flex;
  flex-direction: column;
  transition: border-color var(--transition-fast), transform var(--transition-smooth);
}

.gallery-card:hover {
  border-color: var(--border-focus);
  transform: translateY(-4px);
}

.gallery-card-header {
  margin-bottom: 20px;
}

.gallery-card-num {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-tertiary);
  margin-bottom: 6px;
  letter-spacing: 0.08em;
}

.gallery-card-title {
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: -0.015em;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.gallery-card-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.45;
}

.gallery-mockup {
  background: #000000;
  border-radius: 28px;
  padding: 8px;
  border: 1px solid #27272a;
  margin-top: auto;
  overflow: hidden;
}

.gallery-mockup img {
  border-radius: 20px;
  width: 100%;
  aspect-ratio: 9 / 19.5;
  object-fit: cover;
}

/* ==========================================================================
   Feature Grid (Engineered Architecture)
   ========================================================================== */

.section-features {
  padding: 100px 0;
  border-top: 1px solid var(--border-subtle);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 56px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 32px 28px;
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
}

.feature-card:hover {
  border-color: var(--border-focus);
  background: var(--bg-elevated);
}

.feature-icon-box {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 22px;
  color: var(--text-primary);
}

.feature-title {
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.feature-text {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.55;
}

/* ==========================================================================
   Comparison Table (Apple Style)
   ========================================================================== */

.section-compare {
  padding: 100px 0;
  border-top: 1px solid var(--border-subtle);
}

.compare-table-wrapper {
  margin-top: 56px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  overflow-x: auto;
}

.compare-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
}

.compare-table th,
.compare-table td {
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-subtle);
  font-size: 0.925rem;
}

.compare-table th {
  background: var(--bg-surface);
  font-weight: 600;
  color: var(--text-secondary);
  font-size: 0.8125rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.compare-table th.col-highlight,
.compare-table td.col-highlight {
  background: rgba(255, 255, 255, 0.02);
  color: var(--text-primary);
  font-weight: 600;
  border-left: 1px solid var(--border-subtle);
  border-right: 1px solid var(--border-subtle);
}

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

.check-icon {
  color: var(--accent-green);
  display: inline-flex;
}

.cross-icon {
  color: var(--text-tertiary);
  display: inline-flex;
}

/* ==========================================================================
   Clean Ad Zone (Monetization Container)
   ========================================================================== */

.section-ad-banner {
  padding: 40px 0;
}

.ad-card-container {
  background: var(--bg-surface);
  border: 1px dashed var(--border-focus);
  border-radius: var(--radius-md);
  padding: 24px;
  text-align: center;
  min-height: 120px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.ad-label {
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-tertiary);
  margin-bottom: 8px;
}

/* ==========================================================================
   Installation Guide
   ========================================================================== */

.section-install {
  padding: 100px 0;
  border-top: 1px solid var(--border-subtle);
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 56px;
}

.step-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 32px 28px;
}

.step-badge {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--text-primary);
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

.step-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.step-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ==========================================================================
   FAQ Section (Accordion)
   ========================================================================== */

.section-faq {
  padding: 100px 0;
  border-top: 1px solid var(--border-subtle);
}

.faq-list {
  max-width: 820px;
  margin: 56px auto 0;
}

.faq-item {
  border-bottom: 1px solid var(--border-subtle);
}

.faq-button {
  width: 100%;
  text-align: left;
  background: transparent;
  border: none;
  padding: 24px 0;
  color: var(--text-primary);
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  font-family: inherit;
}

.faq-icon {
  transition: transform var(--transition-fast);
  color: var(--text-secondary);
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
  color: var(--text-primary);
}

.faq-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-smooth), opacity var(--transition-smooth);
  opacity: 0;
}

.faq-item.active .faq-content {
  max-height: 280px;
  opacity: 1;
}

.faq-body {
  padding-bottom: 24px;
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ==========================================================================
   Footer
   ========================================================================== */

.footer {
  border-top: 1px solid var(--border-subtle);
  padding: 60px 0 40px;
  background: #000000;
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

.footer-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 40px;
  flex-wrap: wrap;
  gap: 32px;
}

.footer-links {
  display: flex;
  gap: 28px;
  list-style: none;
  flex-wrap: wrap;
}

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

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

.footer-disclaimer {
  max-width: 820px;
  font-size: 0.75rem;
  color: var(--text-tertiary);
  line-height: 1.6;
  margin-bottom: 28px;
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 24px;
  border-top: 1px solid var(--border-subtle);
  flex-wrap: wrap;
  gap: 16px;
}

/* ==========================================================================
   Sponsor / Native Ad Section (Apple Minimalist)
   ========================================================================== */

.section-sponsor {
  padding: 40px 0;
  background-color: var(--bg-primary);
}

.sponsor-card {
  max-width: 980px;
  margin: 0 auto;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px 20px 20px;
  position: relative;
  text-align: center;
  overflow: hidden;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
}

.sponsor-label {
  display: inline-block;
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-tertiary);
  margin-bottom: 14px;
}

.sponsor-content {
  width: 100%;
  min-height: 90px;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
}

.sponsor-content > div {
  width: 100% !important;
  max-width: 100% !important;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */

@media (max-width: 1024px) {
  .gallery-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
  }
  .gallery-grid {
    grid-template-columns: 1fr;
    max-width: 360px;
    margin-left: auto;
    margin-right: auto;
  }
  .features-grid {
    grid-template-columns: 1fr;
  }
  .steps-grid {
    grid-template-columns: 1fr;
  }
  .hero-section {
    padding: 60px 0 40px;
  }
  .cta-group {
    flex-direction: column;
    width: 100%;
  }
  .btn {
    width: 100%;
  }
}