:root {
  --bg-canvas: #091e24;
  --bg-surface: #0d2a33;
  --bg-surface-elevated: #133a46;
  --bg-surface-hover: #194857;
  --text-primary: #e0f2f1;
  --text-muted: #8faeb2;
  --accent-primary: #ff6f59;
  --accent-hover: #ff8573;
  --border-subtle: rgba(224, 242, 241, 0.18);
  --border-highlight: rgba(255, 111, 89, 0.4);
  --radius-sm: 4px;
  --max-reading: 70ch;
  --font-main: "Trebuchet MS", "Segoe UI", system-ui, sans-serif;
  --ease-kinetic: cubic-bezier(0.16, 1, 0.3, 1);
}

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

body {
  background-color: var(--bg-canvas);
  color: var(--text-primary);
  font-family: var(--font-main);
  line-height: 1.7;
  font-size: 1.05rem;
  overflow-wrap: anywhere;
  hyphens: auto;
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Atmospheric Ambient Glows */
body::before {
  content: "";
  position: absolute;
  top: 0;
  left: 20%;
  width: 50vw;
  height: 50vw;
  max-width: 600px;
  max-height: 600px;
  background: radial-gradient(circle, rgba(255, 111, 89, 0.08) 0%, rgba(13, 42, 51, 0) 70%);
  pointer-events: none;
  z-index: 0;
}

/* Header & Navigation */
header.site-header {
  position: relative;
  width: 100%;
  background: rgba(13, 42, 51, 0.85);
  border-bottom: 1px solid var(--border-subtle);
  padding: 1.25rem 2rem;
  z-index: 100;
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-link {
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--text-primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-align: left;
}

.brand-mark {
  color: var(--accent-primary);
  font-size: 1.4rem;
}

nav.main-nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

nav.main-nav a {
  color: var(--text-primary);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  transition: color 0.2s ease;
  position: relative;
  padding: 0.25rem 0;
}

nav.main-nav a::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--accent-primary);
  transition: width 0.25s var(--ease-kinetic);
}

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

nav.main-nav a:hover {
  color: var(--accent-primary);
}

.nav-toggle-btn {
  display: none;
  background: none;
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-sm);
  line-height: 1;
}

/* Mobile Nav Drawer */
.mobile-nav-panel {
  display: none;
  flex-direction: column;
  background: var(--bg-surface-elevated);
  border-bottom: 1px solid var(--border-subtle);
  padding: 1.5rem 2rem;
  gap: 1rem;
}

.mobile-nav-panel.open {
  display: flex;
}

.mobile-nav-panel a {
  color: var(--text-primary);
  text-decoration: none;
  font-size: 1.1rem;
  padding: 0.4rem 0;
  border-bottom: 1px solid rgba(224, 242, 241, 0.08);
}

.mobile-nav-panel a:hover {
  color: var(--accent-primary);
}

/* Layout Core */
main {
  flex: 1 0 auto;
  width: 100%;
  position: relative;
  z-index: 1;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.reading-spine {
  max-width: var(--max-reading);
  margin-left: auto;
  margin-right: auto;
}

/* Typography */
h1, h2, h3, h4 {
  color: var(--text-primary);
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 1rem;
}

h1 {
  font-size: clamp(2.1rem, 4.5vw, 3.2rem);
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  margin-top: 2.5rem;
  border-left: 3px solid var(--accent-primary);
  padding-left: 0.8rem;
}

h3 {
  font-size: 1.35rem;
  margin-top: 1.5rem;
}

p {
  margin-bottom: 1.3rem;
  color: var(--text-primary);
}

.lead-text {
  font-size: 1.2rem;
  line-height: 1.8;
  color: #c7e3e4;
  margin-bottom: 2rem;
}

.meta-info {
  font-size: 0.9rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.5rem;
}

/* Hero Section */
.hero-typographic {
  padding: 4.5rem 0 3.5rem;
  border-bottom: 1px solid var(--border-subtle);
  background: radial-gradient(circle at top right, rgba(255, 111, 89, 0.05), transparent 60%);
}

.hero-typographic h1 {
  margin-bottom: 1.25rem;
}

/* Buttons */
.btn-primary {
  display: inline-block;
  background-color: var(--accent-primary);
  color: #0d2a33;
  font-weight: 700;
  padding: 0.85rem 1.75rem;
  border-radius: var(--radius-sm);
  text-decoration: none;
  border: 1px solid var(--accent-primary);
  cursor: pointer;
  transition: background-color 0.2s ease, transform 0.2s ease;
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  transform: translateY(-2px);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  color: var(--accent-primary);
  text-decoration: none;
  font-weight: 600;
  margin-left: 1.5rem;
  border-bottom: 1px solid transparent;
  transition: border-bottom-color 0.2s ease;
}

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

/* Cards & Grid */
.grid-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(290px, 1fr));
  gap: 1.75rem;
  margin: 2.5rem 0;
}

.acoustic-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: border-color 0.25s ease, background-color 0.25s ease;
}

.acoustic-card:hover {
  border-color: var(--border-highlight);
  background-color: var(--bg-surface-elevated);
}

.card-media {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  margin-bottom: 1.25rem;
  background-color: #07151a;
}

/* Breakout Containers */
.breakout-quote {
  margin: 3rem 0;
  padding: 2.5rem;
  background: var(--bg-surface);
  border-left: 4px solid var(--accent-primary);
  border-radius: var(--radius-sm);
}

.breakout-quote blockquote {
  font-size: 1.35rem;
  font-style: italic;
  line-height: 1.6;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.breakout-quote cite {
  font-size: 0.95rem;
  color: var(--text-muted);
  font-style: normal;
  display: block;
}

/* Responsive Table */
.table-wrapper {
  overflow-x: auto;
  margin: 2rem 0;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
}

table.acoustic-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  background: var(--bg-surface);
}

table.acoustic-table th,
table.acoustic-table td {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-subtle);
}

table.acoustic-table th {
  background: var(--bg-surface-elevated);
  font-weight: 700;
  color: var(--accent-primary);
  font-size: 0.95rem;
  letter-spacing: 0.04em;
}

table.acoustic-table tr:hover td {
  background-color: var(--bg-surface-hover);
}

/* Interactive Frequency Tool */
.formatter-tool {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 2rem;
  margin: 2.5rem 0;
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 600;
  font-size: 0.95rem;
}

.form-input, .form-textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  background: var(--bg-canvas);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 1rem;
}

.form-input:focus, .form-textarea:focus {
  outline: none;
  border-color: var(--accent-primary);
}

.tool-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1.5rem;
}

.tool-result-box {
  margin-top: 1.5rem;
  padding: 1rem;
  background: #06161b;
  border: 1px dashed var(--border-subtle);
  border-radius: var(--radius-sm);
  font-family: monospace;
  white-space: pre-wrap;
  font-size: 0.95rem;
  color: #a8dadc;
}

/* Scroll Reveal */
.reveal-item {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s var(--ease-kinetic), transform 0.6s var(--ease-kinetic);
}

.reveal-visible {
  opacity: 1;
  transform: translateY(0);
}

/* FAQ Accordion */
.faq-block {
  margin-bottom: 1.5rem;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
}

.faq-title {
  padding: 1.25rem;
  font-size: 1.15rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
}

.faq-title::after {
  content: "+";
  font-size: 1.4rem;
  color: var(--accent-primary);
  transition: transform 0.2s ease;
}

.faq-block.active .faq-title::after {
  content: "−";
}

.faq-content {
  display: none;
  padding: 0 1.25rem 1.25rem 1.25rem;
  border-top: 1px solid rgba(224, 242, 241, 0.08);
  color: #c7e3e4;
}

.faq-block.active .faq-content {
  display: block;
}

/* Footer */
footer.site-footer {
  background: #06161b;
  border-top: 1px solid var(--border-subtle);
  padding: 3rem 1.5rem 2rem;
  margin-top: 4rem;
  text-align: center;
}

.footer-nav {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.footer-nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.2s ease;
}

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

.footer-meta {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
  max-width: 800px;
  margin: 0 auto;
}

.footer-meta a {
  color: var(--text-primary);
  text-decoration: none;
}

.footer-meta a:hover {
  color: var(--accent-primary);
}

/* Responsive Media Queries */
@media (max-width: 768px) {
  nav.main-nav {
    display: none;
  }
  .nav-toggle-btn {
    display: block;
  }
  .hero-typographic {
    padding: 3rem 0 2rem;
  }
  .btn-secondary {
    display: block;
    margin-left: 0;
    margin-top: 1rem;
  }
  .breakout-quote {
    padding: 1.5rem;
  }
}

@media (prefers-reduced-motion: reduce){*,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important;scroll-behavior:auto!important}}