:root {
  --bg-canvas: #1c1f24;
  --bg-surface: #28363a;
  --text-primary: #e5e7eb;
  --text-muted: #bdcfcb;
  --accent-primary: #14b8a6;
  --border-subtle: #637875;
  --font-serif: Charter, Cambria, Georgia, "Times New Roman", serif;
  --radius: 4px;
  --max-width: 1140px;
  --reading-width: 70ch;
}

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

html {
  font-size: 100%;
  scroll-behavior: smooth;
  background-color: var(--bg-canvas);
  color: var(--text-primary);
}

body {
  font-family: var(--font-serif);
  line-height: 1.65;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  position: relative;
  background: radial-gradient(circle at 15% 10%, #202b30 0%, #1c1f24 55%, #15181b 100%);
}

.skip-link {
  position: absolute;
  top: -999px;
  left: 1rem;
  background: var(--accent-primary);
  color: #1c1f24;
  padding: 0.5rem 1rem;
  font-weight: 700;
  border-radius: var(--radius);
  z-index: 1000;
}
.skip-link:focus {
  top: 1rem;
}

/* Header & Navigation */
.site-header {
  position: relative;
  width: 100%;
  border-bottom: 1px solid var(--border-subtle);
  background: rgba(28, 31, 36, 0.95);
  padding: 10px clamp(1rem, 4vw, 2.5rem);
}

.header-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  color: var(--text-primary);
  margin-right: auto;
}

.brand-glyph {
  width: 24px;
  height: 24px;
  border: 1.5px solid var(--accent-primary);
  border-radius: var(--radius);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-primary);
  font-size: 0.8rem;
  font-weight: 700;
}

.brand-title {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.menu-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  width: 44px;
  height: 44px;
  border-radius: var(--radius);
  font-size: 1.25rem;
  cursor: pointer;
  align-items: center;
  justify-content: center;
}
.menu-toggle:focus-visible {
  outline: 2px solid var(--accent-primary);
}

.site-nav {
  margin-top: 8px;
  display: flex;
  justify-content: center;
  border-top: 1px solid rgba(99, 120, 117, 0.3);
  padding-top: 8px;
}

.nav-list {
  list-style: none;
  display: flex;
  gap: clamp(0.75rem, 2vw, 1.75rem);
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
}

.nav-link {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  padding: 0.3rem 0.2rem;
  border-bottom: 2px solid transparent;
  transition: color 0.2s, border-color 0.2s;
}

.nav-link:hover, .nav-link[aria-current="page"] {
  color: var(--accent-primary);
  border-bottom-color: var(--accent-primary);
}

/* Primary Hero (Text-Only Charcoal to Teal Field) */
.hero {
  padding: clamp(3rem, 7vw, 6rem) clamp(1rem, 4vw, 2.5rem);
  background: linear-gradient(175deg, #1c1f24 0%, #202c31 40%, #163638 100%);
  border-bottom: 1px solid var(--border-subtle);
  position: relative;
}

.hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.folio-tag {
  font-variant: small-caps;
  letter-spacing: 0.12em;
  color: var(--accent-primary);
  font-size: 0.9rem;
  display: inline-block;
  margin-bottom: 1rem;
}

.hero h1 {
  font-size: clamp(2.4rem, 5.5vw, 4.2rem);
  line-height: 1.1;
  font-weight: 400;
  max-width: 20ch;
  color: #f3f4f6;
  margin-bottom: 1.5rem;
  overflow-wrap: anywhere;
  hyphens: auto;
}

.hero-lead {
  max-width: var(--reading-width);
  font-size: clamp(1.05rem, 1.8vw, 1.25rem);
  color: var(--text-muted);
  margin-bottom: 2rem;
}

/* Primary Button & Anchors */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: var(--accent-primary);
  color: #1c1f24;
  font-weight: 700;
  text-decoration: none;
  padding: 0.75rem 1.6rem;
  border-radius: var(--radius);
  border: 1px solid var(--accent-primary);
  min-height: 44px;
  cursor: pointer;
  transition: background-color 0.2s, transform 0.1s;
}

.btn-primary:hover {
  background-color: #2dd4bf;
  color: #0f172a;
}

.text-action {
  color: var(--accent-primary);
  text-decoration: underline;
  text-underline-offset: 4px;
  font-weight: 600;
  transition: letter-spacing 0.2s, text-underline-offset 0.2s;
}

.text-action:hover {
  letter-spacing: 0.02em;
  text-underline-offset: 6px;
}

/* Spine Sectioning Structure */
main {
  flex: 1;
}

.folio-spine {
  position: relative;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem clamp(1rem, 3vw, 2rem);
}

.spine-track {
  position: relative;
}

.spine-track::before {
  content: "";
  position: absolute;
  top: 1rem;
  bottom: 2rem;
  left: 2rem;
  width: 1px;
  background: var(--border-subtle);
  opacity: 0.4;
  z-index: 1;
}

.section-block {
  position: relative;
  margin-bottom: 3.5rem;
  padding-left: clamp(2.5rem, 5vw, 4.5rem);
  z-index: 2;
}

.spine-marker {
  position: absolute;
  left: 1.15rem;
  top: 0.2rem;
  width: 1.7rem;
  height: 1.7rem;
  background: var(--bg-surface);
  border: 1.5px solid var(--accent-primary);
  color: var(--accent-primary);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  z-index: 3;
}

.section-label {
  font-variant: small-caps;
  color: var(--accent-primary);
  letter-spacing: 0.1em;
  font-size: 0.85rem;
  margin-bottom: 0.35rem;
  display: block;
}

.section-heading {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  line-height: 1.25;
  margin-bottom: 1rem;
  color: #ffffff;
}

.section-prose {
  max-width: var(--reading-width);
  color: var(--text-muted);
  font-size: 1.05rem;
  margin-bottom: 1.5rem;
}

/* Translucent Cards & Layout Variations */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(290px, 1fr));
  gap: 1.5rem;
  margin: 1.5rem 0;
}

.folio-card {
  background: rgba(40, 54, 58, 0.7);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
}

.folio-card h3 {
  font-size: 1.25rem;
  margin-bottom: 0.6rem;
  color: var(--text-primary);
}

.folio-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  flex: 1;
  margin-bottom: 1rem;
}

/* Horizontal Split Component */
.split-card {
  display: flex;
  flex-direction: column;
  background: rgba(40, 54, 58, 0.6);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  overflow: hidden;
  margin: 1.5rem 0;
}

@media (min-width: 769px) {
  .split-card {
    flex-direction: row;
  }
  .split-card .card-media {
    flex: 0 0 45%;
  }
  .split-card .card-content {
    flex: 1;
  }
}

.card-media {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 10;
  background-color: #21292e;
}

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

.card-content {
  padding: clamp(1.2rem, 3vw, 2rem);
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.card-content h3 {
  font-size: 1.4rem;
  margin-bottom: 0.6rem;
  color: #fff;
}

.card-content p {
  color: var(--text-muted);
  margin-bottom: 1.2rem;
  max-width: var(--reading-width);
}

.card-diagram-caption {
  font-size: 0.8rem;
  color: var(--accent-primary);
  font-variant: small-caps;
  letter-spacing: 0.08em;
  margin-top: 0.4rem;
  display: block;
}

/* Waterfall & Sound Profile Comparison Table */
.table-scroll-wrapper {
  overflow-x: auto;
  margin: 1.5rem 0;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  background: var(--bg-surface);
}

table.folio-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  min-width: 550px;
}

table.folio-table th, table.folio-table td {
  padding: 0.85rem 1.1rem;
  border-bottom: 1px solid rgba(99, 120, 117, 0.35);
  font-size: 0.95rem;
}

table.folio-table th {
  background: rgba(28, 31, 36, 0.85);
  color: var(--accent-primary);
  font-variant: small-caps;
  letter-spacing: 0.08em;
  font-weight: 700;
}

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

table.folio-table td {
  color: var(--text-muted);
}

table.folio-table td strong {
  color: var(--text-primary);
}

/* FAQ Disclosures */
.faq-stack {
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
  margin: 1.5rem 0;
}

details.faq-item {
  background: rgba(40, 54, 58, 0.55);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  padding: 0.9rem 1.2rem;
  transition: background-color 0.2s;
}

details.faq-item[open] {
  background: rgba(40, 54, 58, 0.85);
  border-color: var(--accent-primary);
}

summary.faq-question {
  cursor: pointer;
  font-weight: 600;
  font-size: 1.05rem;
  color: #fff;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

summary.faq-question::-webkit-details-marker {
  display: none;
}

summary.faq-question::after {
  content: "+";
  color: var(--accent-primary);
  font-size: 1.3rem;
  margin-left: 0.8rem;
}

details[open] summary.faq-question::after {
  content: "—";
}

.faq-answer {
  margin-top: 0.8rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* Drafting Tool Form */
.draft-tool {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  padding: clamp(1.2rem, 3vw, 2rem);
  margin-top: 1.5rem;
}

.form-group {
  margin-bottom: 1.2rem;
  display: flex;
  flex-direction: column;
}

.form-group label {
  font-size: 0.9rem;
  color: var(--text-primary);
  margin-bottom: 0.35rem;
}

.form-group input, .form-group select, .form-group textarea {
  background: #1c1f24;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  padding: 0.65rem 0.8rem;
  color: var(--text-primary);
  font-family: inherit;
  font-size: 0.95rem;
  min-height: 44px;
}

.form-group textarea {
  min-height: 120px;
  resize: vertical;
}

.form-group input:focus, .form-group select:focus, .form-group textarea:focus {
  outline: 2px solid var(--accent-primary);
  border-color: transparent;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

@media (min-width: 600px) {
  .form-row {
    grid-template-columns: 1fr 1fr;
  }
}

.button-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1rem;
}

.tool-output {
  margin-top: 1.5rem;
  background: #15181a;
  border: 1px dashed var(--border-subtle);
  padding: 1rem;
  border-radius: var(--radius);
  white-space: pre-wrap;
  font-family: monospace;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.tool-status {
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: var(--accent-primary);
  min-height: 1.2rem;
}

/* Standard Reading Article Style */
.article-container {
  max-width: var(--reading-width);
  margin: 0 auto;
  padding: clamp(2rem, 5vw, 4rem) 1.25rem;
}

.article-container h1 {
  font-size: clamp(2rem, 4.5vw, 3.2rem);
  line-height: 1.15;
  color: #fff;
  margin-bottom: 1.5rem;
  overflow-wrap: anywhere;
}

.article-container h2 {
  font-size: clamp(1.4rem, 2.8vw, 1.9rem);
  margin: 2.2rem 0 0.8rem;
  color: #f3f4f6;
  border-bottom: 1px solid rgba(99, 120, 117, 0.4);
  padding-bottom: 0.4rem;
}

.article-container p {
  color: var(--text-muted);
  margin-bottom: 1.2rem;
  font-size: 1.05rem;
}

.article-container ul, .article-container ol {
  color: var(--text-muted);
  margin: 1rem 0 1.5rem 1.8rem;
}

.article-container li {
  margin-bottom: 0.5rem;
}

/* Site Footer */
.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--border-subtle);
  background: #17191d;
  padding: 3rem clamp(1rem, 4vw, 2.5rem) 2rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

@media (min-width: 768px) {
  .footer-inner {
    grid-template-columns: 2fr 1fr 1fr;
  }
}

.footer-brand a {
  color: #fff;
  font-weight: 700;
  text-decoration: none;
  font-size: 1.05rem;
}

.footer-address {
  font-style: normal;
  margin-top: 0.6rem;
  line-height: 1.5;
  color: var(--text-muted);
}

.footer-col h4 {
  color: var(--accent-primary);
  font-variant: small-caps;
  letter-spacing: 0.08em;
  font-size: 0.95rem;
  margin-bottom: 0.8rem;
}

.footer-col ul {
  list-style: none;
}

.footer-col li {
  margin-bottom: 0.4rem;
}

.footer-col a {
  color: var(--text-muted);
  text-decoration: none;
}

.footer-col a:hover {
  color: var(--accent-primary);
  text-decoration: underline;
}

.footer-bottom {
  max-width: var(--max-width);
  margin: 2rem auto 0;
  padding-top: 1.2rem;
  border-top: 1px solid rgba(99, 120, 117, 0.25);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem;
  font-size: 0.85rem;
}

/* Responsive Overrides */
@media (max-width: 768px) {
  .menu-toggle {
    display: inline-flex;
  }
  
  .site-nav {
    display: none;
    width: 100%;
    margin-top: 10px;
    padding-top: 10px;
  }

  .site-nav.open {
    display: block;
  }

  .nav-list {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.8rem;
  }

  .nav-link {
    display: block;
    width: 100%;
    padding: 0.5rem 0;
  }

  .spine-track::before {
    left: 1rem;
  }

  .section-block {
    padding-left: 2.2rem;
  }

  .spine-marker {
    left: 0.25rem;
  }
}

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