/* ---------------------------------------------------------
   Basic variables
   --------------------------------------------------------- */

:root {
  --background: #ffffff;
  --surface: #f5f7fa;
  --surface-strong: #e9eef4;

  --text: #1f2933;
  --text-muted: #52606d;

  --heading: #102a43;
  --accent: #1f5f8b;
  --accent-dark: #164665;

  --border: #d8e1e8;

  --content-width: 1040px;
  --text-width: 850px;

  --radius: 8px;
}


/* ---------------------------------------------------------
   Global layout
   --------------------------------------------------------- */

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;

  background: var(--background);
  color: var(--text);

  font-family:
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    Roboto,
    Helvetica,
    Arial,
    sans-serif;

  font-size: 17px;
  line-height: 1.65;
}

.container {
  width: min(
    calc(100% - 40px),
    var(--content-width)
  );

  margin-left: auto;
  margin-right: auto;
}


/* ---------------------------------------------------------
   Header
   --------------------------------------------------------- */

.site-header {
  padding: 56px 0 48px;

  background:
    linear-gradient(
      135deg,
      #102a43,
      #1f5f8b
    );

  color: #ffffff;
}

.eyebrow {
  margin: 0 0 10px;

  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;

  opacity: 0.82;
}

.site-title {
  display: block;

  max-width: 850px;

  color: #ffffff;
  text-decoration: none;

  font-size: clamp(
    2rem,
    5vw,
    3.4rem
  );

  font-weight: 700;
  line-height: 1.12;
}

.site-title:hover {
  text-decoration: underline;
  text-decoration-thickness: 2px;
}

.site-description {
  max-width: 760px;

  margin: 18px 0 0;

  font-size: 1.18rem;
  line-height: 1.5;

  opacity: 0.9;
}


/* ---------------------------------------------------------
   Navigation
   --------------------------------------------------------- */

.site-nav {
  background: #ffffff;
  border-bottom: 1px solid var(--border);

  position: sticky;
  top: 0;
  z-index: 10;
}

.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;

  padding-top: 13px;
  padding-bottom: 13px;
}

.nav-links a {
  color: var(--accent-dark);
  text-decoration: none;

  font-size: 0.95rem;
  font-weight: 650;
}

.nav-links a:hover,
.nav-links a:focus {
  text-decoration: underline;
  text-decoration-thickness: 2px;
}


/* ---------------------------------------------------------
   Main content
   --------------------------------------------------------- */

.main-content {
  min-height: 60vh;

  padding-top: 48px;
  padding-bottom: 72px;
}

.main-content > h1,
.main-content > h2,
.main-content > h3,
.main-content > p,
.main-content > ul,
.main-content > ol,
.main-content > table {
  width: 100%;
  max-width: 100%;
}
.main-content > blockquote {
  max-width: var(--text-width);
}

h1,
h2,
h3,
h4 {
  color: var(--heading);
  line-height: 1.25;
}

h1 {
  margin-top: 0;
  margin-bottom: 24px;

  font-size: clamp(
    2rem,
    4vw,
    2.8rem
  );
}

h2 {
  margin-top: 48px;
  margin-bottom: 18px;

  padding-bottom: 8px;

  border-bottom: 1px solid var(--border);

  font-size: 1.65rem;
}

h3 {
  margin-top: 34px;
  margin-bottom: 12px;

  font-size: 1.25rem;
}

p {
  margin-top: 0;
  margin-bottom: 18px;
}

a {
  color: var(--accent);
}

a:hover {
  color: var(--accent-dark);
}

strong {
  color: var(--heading);
}


/* ---------------------------------------------------------
   Images
   --------------------------------------------------------- */

img {
  display: block;

  max-width: 100%;
  height: auto;

  margin: 28px auto;

  border: 1px solid var(--border);
  border-radius: var(--radius);
}


/* ---------------------------------------------------------
   Lists
   --------------------------------------------------------- */

ul,
ol {
  padding-left: 1.4rem;
}

li {
  margin-bottom: 8px;
}


/* ---------------------------------------------------------
   Tables
   --------------------------------------------------------- */

table {
  width: 100%;

  margin-top: 24px;
  margin-bottom: 32px;

  border-collapse: collapse;

  font-size: 0.94rem;
}

th,
td {
  padding: 11px 13px;

  border: 1px solid var(--border);

  text-align: left;
  vertical-align: top;
}

th {
  background: var(--surface-strong);
  color: var(--heading);

  font-weight: 700;
}

tr:nth-child(even) td {
  background: var(--surface);
}


/* ---------------------------------------------------------
   Reusable content blocks
   --------------------------------------------------------- */

.callout {
  max-width: var(--text-width);

  margin: 30px 0;
  padding: 20px 22px;

  background: var(--surface);

  border-left: 4px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.card-grid {
  display: grid;

  grid-template-columns:
    repeat(
      auto-fit,
      minmax(230px, 1fr)
    );

  gap: 18px;

  margin: 28px 0;
}

.card {
  padding: 22px;

  background: var(--surface);

  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.card h3 {
  margin-top: 0;
}

.page-links {
  max-width: var(--text-width);

  margin: 36px 0;
  padding: 18px 20px;

  background: var(--surface);

  border: 1px solid var(--border);
  border-radius: var(--radius);
}


/* ---------------------------------------------------------
   Research figures and general galleries
   --------------------------------------------------------- */

.figure-grid {
  display: grid;

  grid-template-columns:
    repeat(
      auto-fit,
      minmax(280px, 1fr)
    );

  gap: 24px;

  margin: 30px 0 42px;
}

.figure-card {
  padding: 16px;

  background: var(--surface);

  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.figure-card img {
  width: 100%;
  height: auto;

  margin: 0 0 14px;

  background: #ffffff;
}

.figure-caption {
  margin: 0;

  color: var(--text-muted);

  font-size: 0.9rem;
  line-height: 1.5;
}

.figure-card .figure-caption {
  font-size: 0.88rem;
}


/* Standalone research figures */

.research-figure {
  width: 100%;
  max-width: 980px;

  margin: 30px auto 38px;
}

.research-figure img {
  display: block;

  width: 100%;
  height: auto;

  margin: 0;

  background: #ffffff;

  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.research-figure figcaption {
  max-width: 900px;

  margin: 10px auto 0;

  color: var(--text-muted);

  font-size: 0.9rem;
  line-height: 1.5;
}

/* ---------------------------------------------------------
   Manual layout variant gallery

   Desktop:
   A | B
   C | D

   Image widths approximately preserve the relative
   physical layout dimensions.
   --------------------------------------------------------- */

.figure-grid.manual-variant-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.figure-grid.manual-variant-grid .figure-card {
  display: flex;
  flex-direction: column;
}

.figure-grid.manual-variant-grid .manual-layout-image {
  display: block;
  height: auto;

  margin-left: auto;
  margin-right: auto;
  margin-bottom: 14px;

  object-fit: contain;
}

/* Relative physical width:
   maximum width = 42.9 µm
*/

.figure-grid.manual-variant-grid .layout-a {
  width: 85.55%;
}

.figure-grid.manual-variant-grid .layout-b {
  width: 88.34%;
}

.figure-grid.manual-variant-grid .layout-c {
  width: 100%;
}

.figure-grid.manual-variant-grid .layout-d {
  width: 100%;
}

.figure-grid.manual-variant-grid .figure-caption {
  margin-top: auto;
}


/* ---------------------------------------------------------
   Generator gallery

   Desktop:
   3 columns × 2 rows for MOS-based modules.
   --------------------------------------------------------- */

.figure-grid.generator-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}


/* ---------------------------------------------------------
   Passive generator module
   --------------------------------------------------------- */

.passive-module-card {
  max-width: 520px;

  margin: 28px 0 42px;
  padding: 16px;

  background: var(--surface);

  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.passive-module-card img {
  width: 100%;
  height: auto;

  margin: 0 0 14px;

  background: #ffffff;
}

.passive-module-card .figure-caption {
  margin: 0;
}

/* ---------------------------------------------------------
   Research workflow
   --------------------------------------------------------- */

.research-flow {
  display: flex;
  align-items: stretch;
  gap: 10px;

  width: 100%;

  margin: 30px 0 38px;
  padding-bottom: 8px;

  overflow-x: auto;
}

.research-flow-step {
  display: flex;
  flex-direction: column;
  justify-content: center;

  flex: 1 0 135px;
  min-height: 92px;

  padding: 14px 12px;

  background: var(--surface);

  border: 1px solid var(--border);
  border-radius: var(--radius);

  text-align: center;
}

.research-flow-step strong {
  display: block;

  margin-bottom: 5px;

  color: var(--heading);

  font-size: 0.9rem;
  line-height: 1.3;
}

.research-flow-step span {
  color: var(--text-muted);

  font-size: 0.78rem;
  line-height: 1.35;
}

.research-flow-arrow {
  display: flex;
  align-items: center;
  justify-content: center;

  flex: 0 0 22px;

  color: var(--accent);

  font-size: 1.5rem;
  font-weight: 700;
}

/* ---------------------------------------------------------
   Generator hierarchy
   --------------------------------------------------------- */

.hierarchy-level {
  max-width: 780px;

  margin: 22px 0;
  padding: 20px 22px;

  background: var(--surface);

  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.hierarchy-level h3 {
  margin-top: 0;
}

.hierarchy-arrow {
  max-width: 780px;

  color: var(--accent);

  font-size: 1.8rem;
  font-weight: 700;
  text-align: center;
}

/* ---------------------------------------------------------
   Footer
   --------------------------------------------------------- */

.site-footer {
  padding: 38px 0;

  background: var(--surface);
  border-top: 1px solid var(--border);

  color: var(--text-muted);
}

.footer-content p {
  max-width: 760px;

  margin-bottom: 8px;
}

.footer-small {
  margin-top: 18px;

  font-size: 0.84rem;
}


/* ---------------------------------------------------------
   Tablet layout
   --------------------------------------------------------- */

@media (max-width: 900px) {

  /*
     Generator gallery changes from 3 columns
     to 2 columns on medium-width screens.
  */

  .figure-grid.generator-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

}


/* ---------------------------------------------------------
   Mobile layout
   --------------------------------------------------------- */

@media (max-width: 640px) {

  body {
    font-size: 16px;
  }

  .container {
    width: min(
      calc(100% - 28px),
      var(--content-width)
    );
  }

  .site-header {
    padding: 42px 0 36px;
  }

  .site-nav {
    position: static;
  }

  .nav-links {
    gap: 8px 16px;
  }

  .main-content {
    padding-top: 36px;
  }


  /* Tables */

  table {
    display: block;

    max-width: 100%;
    overflow-x: auto;
  }


  /* Manual A/B/C/D become a single column */

  .figure-grid.manual-variant-grid {
    grid-template-columns: 1fr;
  }


  /* Generator modules become a single column */

  .figure-grid.generator-grid {
    grid-template-columns: 1fr;
  }


  /* Passive module uses the full available width */

  .passive-module-card {
    max-width: 100%;
  }

  /* Research workflows become vertical on mobile */

  .research-flow {
    flex-direction: column;

    overflow-x: visible;
  }

  .research-flow-step {
    flex-basis: auto;
    min-height: 0;
  }

  .research-flow-arrow {
    flex-basis: auto;
    height: 20px;

    transform: rotate(90deg);
  }

}