/* ==========================================================================
       APLOMO // CORPORATE IDENTITY V2.0 + APPLE FLUID DESIGN SYSTEM
       ========================================================================== */
    :root {
      color-scheme: light;
      --charcoal: #121316;
      --bronze-steel: #2A2D34;
      --cadmium: #FF5A1F;
      --raw-bone: #F5F4F0;
      --warm-parchment: #FAFAF8;
      --hairline: #E2E0D8;
      --text-muted: #555963;
      --text-muted-dark: #9EA3AE;

      /* Semantic Theme Tokens */
      --bg-page: #F5F4F0;
      --bg-surface: #FAFAF8;
      --bg-header: rgba(245, 244, 240, 0.78);
      --bg-header-scrolled: rgba(245, 244, 240, 0.88);
      --border-header: rgba(18, 19, 22, 0.07);
      --border-subtle: #E2E0D8;
      --text-main: #121316;
      --text-secondary: #555963;
      --grid-line: rgba(226, 224, 216, 0.55);

      --font-display: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
      --font-body: 'Inter', -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
      --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, monospace;

      --max-width: 1140px;
    }

    [data-theme="dark"] {
      color-scheme: dark;
      --bg-page: #0E1015;
      --bg-surface: #15181E;
      --bg-header: rgba(14, 16, 21, 0.82);
      --bg-header-scrolled: rgba(14, 16, 21, 0.92);
      --border-header: rgba(255, 255, 255, 0.08);
      --border-subtle: #262A33;
      --hairline: #262A33;
      --text-main: #F5F4F0;
      --text-secondary: #9EA3AE;
      --text-muted: #9EA3AE;
      --grid-line: rgba(255, 255, 255, 0.045);
    }

    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      -webkit-tap-highlight-color: transparent;
    }

    /* Apple-style Fluid View Transition Cross-Fade */
    ::view-transition-old(root),
    ::view-transition-new(root) {
      animation-duration: 300ms;
      animation-timing-function: cubic-bezier(0.16, 1, 0.3, 1);
    }

    @media (prefers-reduced-motion: reduce) {
      ::view-transition-group(root),
      ::view-transition-old(root),
      ::view-transition-new(root) {
        animation: none !important;
      }
    }

    html {
      font: 100%/1.55 var(--font-body);
      background-color: var(--bg-page);
      color: var(--text-main);
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
      scroll-behavior: smooth;
    }

    body {
      overflow-x: hidden;
    }

    /* Technical Architectural Grid Background */
    .architectural-canvas {
      background-color: var(--bg-page);
      background-image:
        linear-gradient(to right, var(--grid-line) 1px, transparent 1px),
        linear-gradient(to bottom, var(--grid-line) 1px, transparent 1px);
      background-size: 64px 64px;
    }

    .container {
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 2rem;
    }

    /* ==========================================================================
       TYPOGRAPHY: OPTICAL SIZING, SIZE-SPECIFIC TRACKING & LEADING
       ========================================================================== */
    .display-h1 {
      font-family: var(--font-display);
      font-weight: 800;
      font-size: clamp(2.3rem, 4.5vw, 3.55rem);
      line-height: 1.06;
      letter-spacing: -0.03em;
      font-optical-sizing: auto;
    }

    .section-h2 {
      font-family: var(--font-display);
      font-weight: 700;
      font-size: clamp(1.65rem, 2.8vw, 2.25rem);
      line-height: 1.15;
      letter-spacing: -0.022em;
      font-optical-sizing: auto;
    }

    .card-h3 {
      font-family: var(--font-display);
      font-weight: 700;
      font-size: 1.18rem;
      line-height: 1.28;
      letter-spacing: -0.012em;
    }

    .body-lead {
      font-family: var(--font-body);
      font-weight: 400;
      font-size: clamp(0.98rem, 1.2vw, 1.1rem);
      line-height: 1.6;
      letter-spacing: 0em;
      color: var(--text-muted);
    }

    .system-meta {
      font-family: var(--font-mono);
      font-weight: 600;
      font-size: 0.6875rem;
      line-height: 1.45;
      letter-spacing: 0.05em;
      text-transform: uppercase;
    }

    .plumb-datum {
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
      font-family: var(--font-mono);
      font-size: 0.6875rem;
      font-weight: 600;
      letter-spacing: 0.06em;
      text-transform: uppercase;
      color: var(--cadmium);
    }

    .plumb-datum::before {
      content: "";
      width: 6px;
      height: 6px;
      border-radius: 50%;
      background-color: var(--cadmium);
      flex-shrink: 0;
    }

    /* ==========================================================================
       TRANSLUCENT CHROME & SPRING LANGUAGE SWITCHER
       ========================================================================== */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: var(--bg-header);
      backdrop-filter: blur(20px) saturate(180%);
      -webkit-backdrop-filter: blur(20px) saturate(180%);
      border-bottom: 1px solid var(--border-header);
      transition: background-color 200ms ease, box-shadow 200ms ease, border-color 200ms ease;
    }

    .site-header.scrolled {
      background: var(--bg-header-scrolled);
      box-shadow: 0 8px 30px -12px rgba(18, 19, 22, 0.08);
    }

    [data-theme="dark"] .site-header.scrolled {
      box-shadow: 0 8px 30px -12px rgba(0, 0, 0, 0.5);
    }

    .nav-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 4.25rem;
    }

    .brand-logo-link {
      display: inline-flex;
      align-items: center;
      text-decoration: none;
      padding: 0.4rem 0;
      transition: transform 90ms ease-out;
    }
    .brand-logo-link:active {
      transform: scale(0.97);
    }

    .brand-logo-svg {
      height: 36px;
      width: auto;
      display: block;
    }

    [data-theme="dark"] .brand-logo-svg path[fill="#121316"] {
      fill: #F5F4F0;
    }
    [data-theme="dark"] .brand-logo-svg rect[fill="#F5F4F0"] {
      fill: #0E1015;
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 2.25rem;
      list-style: none;
    }

    .nav-links a {
      color: var(--text-main);
      text-decoration: none;
      font-weight: 500;
      font-size: 0.875rem;
      padding: 0.5rem 0.25rem;
      transition: color 120ms ease, transform 90ms ease-out;
      display: inline-block;
    }
    .nav-links a:hover {
      color: var(--cadmium);
    }
    .nav-links a:active {
      transform: scale(0.96);
    }

    .nav-actions {
      display: flex;
      align-items: center;
      gap: 0.875rem;
    }

    .segmented-lang {
      position: relative;
      display: inline-grid;
      grid-template-columns: 1fr 1fr;
      background: rgba(18, 19, 22, 0.06);
      border: 1px solid rgba(18, 19, 22, 0.08);
      padding: 3px;
      border-radius: 7px;
      user-select: none;
      transition: background-color 150ms ease, border-color 150ms ease;
    }

    [data-theme="dark"] .segmented-lang {
      background: rgba(255, 255, 255, 0.08);
      border-color: rgba(255, 255, 255, 0.12);
    }

    .segmented-lang-pill {
      position: absolute;
      top: 3px;
      bottom: 3px;
      left: 3px;
      width: calc(50% - 3px);
      background: var(--charcoal);
      border-radius: 5px;
      will-change: transform;
      pointer-events: none;
      transition: background-color 150ms ease;
    }

    [data-theme="dark"] .segmented-lang-pill {
      background: #F5F4F0;
    }

    .lang-btn {
      position: relative;
      z-index: 1;
      border: none;
      background: transparent;
      padding: 0.32rem 0.7rem;
      font-family: var(--font-mono);
      font-size: 0.6875rem;
      font-weight: 600;
      color: var(--charcoal);
      cursor: pointer;
      transition: color 140ms ease, transform 80ms ease-out;
    }
    .lang-btn:active {
      transform: scale(0.94);
    }
    .lang-btn.active {
      color: var(--raw-bone);
    }

    [data-theme="dark"] .lang-btn {
      color: #9EA3AE;
    }
    [data-theme="dark"] .lang-btn.active {
      color: #121316;
    }

    /* Apple-style Fluid Theme Switcher Button */
    .theme-toggle-btn {
      position: relative;
      width: 36px;
      height: 36px;
      border-radius: 8px;
      border: 1px solid rgba(18, 19, 22, 0.08);
      background: rgba(18, 19, 22, 0.06);
      color: var(--charcoal);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      user-select: none;
      overflow: hidden;
      transition: background-color 150ms ease, border-color 150ms ease, color 150ms ease, transform 90ms ease-out;
    }

    .theme-toggle-btn:hover {
      background: rgba(18, 19, 22, 0.1);
      border-color: rgba(18, 19, 22, 0.16);
    }

    .theme-toggle-btn:active {
      transform: scale(0.92);
    }

    .theme-toggle-btn .theme-icon {
      position: absolute;
      transition: transform 280ms cubic-bezier(0.16, 1, 0.3, 1), opacity 220ms ease;
    }

    .theme-toggle-btn .theme-icon-sun {
      opacity: 0;
      transform: rotate(90deg) scale(0.45);
    }

    .theme-toggle-btn .theme-icon-moon {
      opacity: 1;
      transform: rotate(0deg) scale(1);
    }

    [data-theme="dark"] .theme-toggle-btn {
      background: rgba(255, 255, 255, 0.08);
      border-color: rgba(255, 255, 255, 0.14);
      color: #F5F4F0;
    }

    [data-theme="dark"] .theme-toggle-btn:hover {
      background: rgba(255, 255, 255, 0.14);
      border-color: rgba(255, 255, 255, 0.24);
    }

    [data-theme="dark"] .theme-toggle-btn .theme-icon-sun {
      opacity: 1;
      transform: rotate(0deg) scale(1);
    }

    [data-theme="dark"] .theme-toggle-btn .theme-icon-moon {
      opacity: 0;
      transform: rotate(-90deg) scale(0.45);
    }

    /* ==========================================================================
       BUTTONS WITH INSTANT POINTER-DOWN FEEDBACK
       ========================================================================== */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 0.55rem;
      padding: 0.8rem 1.5rem;
      font-family: var(--font-display);
      font-weight: 700;
      font-size: 0.86rem;
      letter-spacing: -0.01em;
      text-decoration: none;
      border-radius: 7px;
      cursor: pointer;
      border: 1px solid transparent;
      user-select: none;
      will-change: transform;
      transition: background-color 140ms ease, border-color 140ms ease, transform 90ms ease-out;
    }

    .btn:active {
      transform: scale(0.97);
      transition: transform 60ms ease-out;
    }

    .btn-primary {
      background-color: var(--charcoal);
      color: var(--raw-bone);
      border-color: var(--charcoal);
    }
    .btn-primary:hover {
      background-color: var(--bronze-steel);
      border-color: var(--bronze-steel);
    }

    [data-theme="dark"] .btn-primary {
      background-color: #F5F4F0;
      color: #121316;
      border-color: #F5F4F0;
    }
    [data-theme="dark"] .btn-primary:hover {
      background-color: #FFFFFF;
      border-color: #FFFFFF;
    }

    .btn-cadmium {
      background-color: var(--cadmium);
      color: #FFFFFF;
      border-color: var(--cadmium);
    }
    .btn-cadmium:hover {
      background-color: #e54b14;
      border-color: #e54b14;
    }

    .btn-outline {
      background-color: rgba(250, 250, 248, 0.85);
      backdrop-filter: blur(8px);
      color: var(--charcoal);
      border-color: var(--hairline);
    }
    .btn-outline:hover {
      border-color: var(--charcoal);
      background-color: var(--warm-parchment);
    }

    [data-theme="dark"] .btn-outline {
      background-color: rgba(255, 255, 255, 0.06);
      color: #F5F4F0;
      border-color: rgba(255, 255, 255, 0.16);
    }
    [data-theme="dark"] .btn-outline:hover {
      border-color: var(--cadmium);
      background-color: rgba(255, 255, 255, 0.12);
    }

    /* ==========================================================================
       SECTION 1: CENTERED HERO + REAL GRAVITATIONAL PENDULUM MONOGRAM
       ========================================================================== */
    .hero-section {
      padding: 3.75rem 0 4.5rem;
      border-bottom: 1px solid var(--hairline);
      text-align: center;
      transition: border-color 150ms ease;
    }

    [data-theme="dark"] .hero-section {
      border-bottom-color: var(--border-subtle);
    }

    .hero-inner {
      max-width: 780px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 1.25rem;
    }

    .plumb-emblem-card {
      position: relative;
      background: rgba(250, 250, 248, 0.92);
      backdrop-filter: blur(12px);
      border: 1px solid var(--hairline);
      border-radius: 16px;
      padding: 1.25rem 2rem 0.85rem;
      display: inline-flex;
      flex-direction: column;
      align-items: center;
      gap: 0.4rem;
      cursor: grab;
      touch-action: none;
      user-select: none;
      box-shadow: 0 12px 32px -16px rgba(18, 19, 22, 0.07);
      transition: border-color 150ms ease, background-color 150ms ease, box-shadow 150ms ease;
    }

    .plumb-emblem-card:hover {
      border-color: rgba(18, 19, 22, 0.25);
    }
    .plumb-emblem-card:active {
      cursor: grabbing;
    }

    [data-theme="dark"] .plumb-emblem-card {
      background: rgba(21, 24, 30, 0.9);
      border-color: var(--border-subtle);
      box-shadow: 0 12px 32px -16px rgba(0, 0, 0, 0.55);
    }

    [data-theme="dark"] .plumb-emblem-card:hover {
      border-color: rgba(255, 255, 255, 0.28);
    }

    [data-theme="dark"] .plumb-emblem-card svg path[fill="#121316"] {
      fill: #F5F4F0;
    }

    [data-theme="dark"] .plumb-emblem-card svg rect[fill="#FAFAF8"] {
      fill: #15181E;
    }

    .plumb-emblem-card::before,
    .plumb-emblem-card::after {
      content: "";
      position: absolute;
      width: 10px;
      height: 10px;
      pointer-events: none;
      transition: border-color 150ms ease;
    }
    .plumb-emblem-card::before {
      top: 6px;
      left: 6px;
      border-top: 1.5px solid var(--charcoal);
      border-left: 1.5px solid var(--charcoal);
    }
    .plumb-emblem-card::after {
      bottom: 6px;
      right: 6px;
      border-bottom: 1.5px solid var(--charcoal);
      border-right: 1.5px solid var(--charcoal);
    }

    [data-theme="dark"] .plumb-emblem-card::before {
      border-top-color: #F5F4F0;
      border-left-color: #F5F4F0;
    }
    [data-theme="dark"] .plumb-emblem-card::after {
      border-bottom-color: #F5F4F0;
      border-right-color: #F5F4F0;
    }

    .plumb-readout {
      font-family: var(--font-mono);
      font-size: 0.72rem;
      font-weight: 700;
      letter-spacing: 0.06em;
      color: var(--cadmium);
      min-width: 4.5rem;
      text-align: center;
    }

    .hero-cta-row {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 0.75rem;
      flex-wrap: wrap;
      margin-top: 0.25rem;
    }

    @media (max-width: 640px) {
      .container {
        padding: 0 1.15rem;
      }
      .hero-section {
        padding: 2.25rem 0 2.75rem;
      }
      .display-h1 {
        font-size: clamp(1.95rem, 8.5vw, 2.45rem);
      }
      .body-lead {
        font-size: 0.95rem;
      }
      .hero-cta-row {
        width: 100%;
        flex-direction: column;
        gap: 0.65rem;
      }
      .hero-cta-row .btn {
        width: 100%;
      }
      .plumb-emblem-card {
        padding: 1rem 1.4rem 0.75rem;
      }
    }