/* ==========================================================================
   milkyweb.css — Shared Design System
   Used by: milkyweb.de (static), observatory-guide.org (PHP), spacehistory
   Version: 1.0.0
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Custom Properties
   -------------------------------------------------------------------------- */

:root {
  /* --- Colors: Dark Astro Theme + Glassmorphism --- */
  --color-bg:             #060a14;
  --color-panel:          rgba(10, 14, 26, 0.75);
  --color-card:           rgba(17, 24, 39, 0.7);
  --color-card-hover:     rgba(25, 34, 52, 0.8);
  --color-border:         rgba(255, 255, 255, 0.08);
  --color-border-hover:   rgba(255, 255, 255, 0.15);

  --color-text:           #e2e8f0;
  --color-text-secondary: #94a3b8;
  --color-text-muted:     #64748b;

  --color-accent:         #6592ff;
  --color-accent-hover:   #85adff;
  --color-warm:           #ff6600;
  --color-warm-hover:     #ff8533;

  --color-success:        #22c55e;
  --color-warning:        #eab308;
  --color-error:          #ef4444;

  /* --- Glassmorphism --- */
  --blur-panel:           12px;
  --blur-card:            8px;
  --blur-nav:             16px;

  /* --- Typography --- */
  --font-body:            "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
  --font-heading:         "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
  --font-mono:            "JetBrains Mono", "Fira Code", "Consolas", monospace;

  --text-xs:              0.75rem;
  --text-sm:              0.875rem;
  --text-base:            1rem;
  --text-lg:              1.125rem;
  --text-xl:              1.25rem;
  --text-2xl:             1.5rem;
  --text-3xl:             1.875rem;
  --text-4xl:             2.25rem;

  --leading-tight:        1.25;
  --leading-normal:       1.6;
  --leading-relaxed:      1.75;

  --weight-normal:        400;
  --weight-medium:        500;
  --weight-semibold:      600;
  --weight-bold:          700;

  /* --- Spacing --- */
  --space-1:              0.25rem;
  --space-2:              0.5rem;
  --space-3:              0.75rem;
  --space-4:              1rem;
  --space-5:              1.25rem;
  --space-6:              1.5rem;
  --space-8:              2rem;
  --space-10:             2.5rem;
  --space-12:             3rem;
  --space-16:             4rem;
  --space-20:             5rem;

  /* --- Layout --- */
  --max-width:            1200px;
  --nav-height:           3.5rem;
  --radius-sm:            0.375rem;
  --radius-md:            0.5rem;
  --radius-lg:            0.75rem;
  --radius-xl:            1rem;

  /* --- Transitions --- */
  --transition-fast:      150ms ease;
  --transition-base:      250ms ease;
  --transition-slow:      400ms ease;
}


/* --------------------------------------------------------------------------
   2. Reset & Base
   -------------------------------------------------------------------------- */

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

html {
  font-size: 100%;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-normal);
  line-height: var(--leading-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
}

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

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

ul, ol {
  list-style: none;
}

table {
  border-collapse: collapse;
  width: 100%;
}


/* --------------------------------------------------------------------------
   3. Background — Fullscreen Astro Photo
   -------------------------------------------------------------------------- */

.site-bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  background-color: var(--color-bg);
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}

.site-bg::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    to bottom,
    rgba(6, 10, 20, 0.3) 0%,
    rgba(6, 10, 20, 0.1) 30%,
    rgba(6, 10, 20, 0.1) 70%,
    rgba(6, 10, 20, 0.5) 100%
  );
}


/* --------------------------------------------------------------------------
   4. Typography
   -------------------------------------------------------------------------- */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: var(--weight-bold);
  line-height: var(--leading-tight);
  color: var(--color-warm);
}

h1 { font-size: var(--text-4xl); margin-bottom: var(--space-6); }
h2 { font-size: var(--text-3xl); margin-bottom: var(--space-5); }
h3 { font-size: var(--text-2xl); margin-bottom: var(--space-4); }
h4 { font-size: var(--text-xl);  margin-bottom: var(--space-3); }
h5 { font-size: var(--text-lg);  margin-bottom: var(--space-2); }
h6 { font-size: var(--text-base); margin-bottom: var(--space-2); }

p {
  margin-bottom: var(--space-4);
}

p:last-child {
  margin-bottom: 0;
}

small {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--color-card);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
}

blockquote {
  border-left: 3px solid var(--color-accent);
  padding-left: var(--space-4);
  color: var(--color-text-secondary);
  font-style: italic;
  margin-bottom: var(--space-4);
}


/* --------------------------------------------------------------------------
   5. Layout
   -------------------------------------------------------------------------- */

.site-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.site-main {
  flex: 1;
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-8) var(--space-4);
  padding-top: calc(var(--nav-height) + var(--space-8));
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-4);
}


/* --------------------------------------------------------------------------
   6. Component: Site Navigation
   -------------------------------------------------------------------------- */

.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--nav-height);
  background: var(--color-panel);
  backdrop-filter: blur(var(--blur-nav));
  -webkit-backdrop-filter: blur(var(--blur-nav));
  border-bottom: 1px solid var(--color-border);
}

.site-nav__inner {
  display: flex;
  align-items: center;
  height: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-4);
  gap: var(--space-6);
}

.site-nav__logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
  text-decoration: none;
  color: var(--color-text);
  font-weight: var(--weight-bold);
  font-size: var(--text-lg);
}

.site-nav__logo img {
  height: 1.75rem;
  width: auto;
}

.site-nav__logo:hover {
  color: var(--color-warm);
}

.site-nav__links {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  flex: 1;
  justify-content: center;
}

.site-nav__link {
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background var(--transition-fast);
  white-space: nowrap;
}

.site-nav__link:hover {
  color: var(--color-text);
  background: rgba(255, 255, 255, 0.05);
}

.site-nav__link--active {
  color: var(--color-accent);
}

.site-nav__right {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-shrink: 0;
}

/* Hamburger (mobile) */
.site-nav__toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
  color: var(--color-text);
}

.site-nav__toggle svg {
  width: 1.5rem;
  height: 1.5rem;
}

/* Mobile menu overlay */
.site-nav__mobile {
  display: none;
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  background: var(--color-panel);
  backdrop-filter: blur(var(--blur-nav));
  -webkit-backdrop-filter: blur(var(--blur-nav));
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-4);
  flex-direction: column;
  gap: var(--space-2);
}

.site-nav__mobile.is-open {
  display: flex;
}

.site-nav__mobile .site-nav__link {
  font-size: var(--text-base);
  padding: var(--space-3) var(--space-4);
}


/* --------------------------------------------------------------------------
   7. Component: Language Switcher
   -------------------------------------------------------------------------- */

.lang-switch {
  display: flex;
  align-items: center;
  gap: 0;
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
}

.lang-switch__option {
  padding: var(--space-1) var(--space-2);
  color: var(--color-text-muted);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background var(--transition-fast);
}

.lang-switch__option:hover {
  color: var(--color-text);
}

.lang-switch__option--active {
  color: var(--color-text);
  background: rgba(255, 255, 255, 0.1);
}

.lang-switch__sep {
  color: var(--color-text-muted);
  margin: 0 0.15em;
  user-select: none;
}


/* --------------------------------------------------------------------------
   8. Component: Breadcrumb
   -------------------------------------------------------------------------- */

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-6);
}

.breadcrumb a {
  color: var(--color-text-secondary);
}

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

.breadcrumb__sep {
  color: var(--color-text-muted);
  margin: 0 var(--space-1);
  user-select: none;
}

.breadcrumb__current {
  color: var(--color-text);
}


/* --------------------------------------------------------------------------
   9. Component: Glass Panel (generic container)
   -------------------------------------------------------------------------- */

.glass-panel {
  background: var(--color-panel);
  backdrop-filter: blur(var(--blur-panel));
  -webkit-backdrop-filter: blur(var(--blur-panel));
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}


/* --------------------------------------------------------------------------
   10. Component: Category Card (Home page — 9 categories)
   -------------------------------------------------------------------------- */

.category-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.category-card {
  background: var(--color-card);
  backdrop-filter: blur(var(--blur-card));
  -webkit-backdrop-filter: blur(var(--blur-card));
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  text-decoration: none;
  color: var(--color-text);
  transition: background var(--transition-base),
              border-color var(--transition-base),
              transform var(--transition-base);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.category-card:hover {
  background: var(--color-card-hover);
  border-color: var(--color-border-hover);
  transform: translateY(-2px);
  color: var(--color-text);
}

.category-card__icon {
  font-size: var(--text-3xl);
  line-height: 1;
}

.category-card__name {
  font-size: var(--text-xl);
  font-weight: var(--weight-semibold);
  color: var(--color-warm);
}

.category-card__count {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}


/* --------------------------------------------------------------------------
   11. Component: Topic List (Category page)
   -------------------------------------------------------------------------- */

.topic-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.topic-item {
  background: var(--color-card);
  backdrop-filter: blur(var(--blur-card));
  -webkit-backdrop-filter: blur(var(--blur-card));
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-4) var(--space-5);
  display: flex;
  justify-content: space-between;
  align-items: center;
  text-decoration: none;
  color: var(--color-text);
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.topic-item:hover {
  background: var(--color-card-hover);
  border-color: var(--color-border-hover);
  color: var(--color-text);
}

.topic-item__name {
  font-weight: var(--weight-medium);
}

.topic-item__count {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}


/* --------------------------------------------------------------------------
   12. Component: Link Card (Topic page)
   -------------------------------------------------------------------------- */

.link-card-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.link-card {
  background: var(--color-card);
  backdrop-filter: blur(var(--blur-card));
  -webkit-backdrop-filter: blur(var(--blur-card));
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  transition: border-color var(--transition-fast);
}

.link-card:hover {
  border-color: var(--color-border-hover);
}

.link-card__title {
  font-size: var(--text-lg);
  font-weight: var(--weight-semibold);
  margin-bottom: var(--space-2);
}

.link-card__title a {
  color: var(--color-accent);
}

.link-card__title a:hover {
  color: var(--color-accent-hover);
}

.link-card__desc {
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
  margin-bottom: var(--space-3);
}

.link-card__meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

.link-card__tag {
  background: rgba(101, 146, 255, 0.12);
  color: var(--color-accent);
  padding: 0.15em 0.5em;
  border-radius: var(--radius-sm);
  font-size: var(--text-xs);
}


/* --------------------------------------------------------------------------
   13. Component: Data Table (Observatory list, Space History results)
   -------------------------------------------------------------------------- */

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
}

.data-table thead {
  border-bottom: 2px solid var(--color-border);
}

.data-table th {
  text-align: left;
  padding: var(--space-3) var(--space-4);
  font-weight: var(--weight-semibold);
  color: var(--color-text-secondary);
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.data-table td {
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-border);
  vertical-align: top;
}

.data-table tbody tr {
  transition: background var(--transition-fast);
}

.data-table tbody tr:hover {
  background: rgba(255, 255, 255, 0.03);
}

.data-table--glass {
  background: var(--color-card);
  backdrop-filter: blur(var(--blur-card));
  -webkit-backdrop-filter: blur(var(--blur-card));
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}


/* --------------------------------------------------------------------------
   14. Component: Observatory Detail
   -------------------------------------------------------------------------- */

.observatory-detail {
  background: var(--color-card);
  backdrop-filter: blur(var(--blur-card));
  -webkit-backdrop-filter: blur(var(--blur-card));
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
}

.observatory-detail__header {
  margin-bottom: var(--space-6);
}

.observatory-detail__name {
  font-size: var(--text-3xl);
  color: var(--color-warm);
  margin-bottom: var(--space-2);
}

.observatory-detail__location {
  color: var(--color-text-secondary);
  font-size: var(--text-lg);
}

.observatory-detail__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
}

.observatory-detail__field {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.observatory-detail__label {
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.observatory-detail__value {
  font-size: var(--text-base);
}


/* --------------------------------------------------------------------------
   15. Component: Forms (Questionnaire, Search)
   -------------------------------------------------------------------------- */

.form-group {
  margin-bottom: var(--space-5);
}

.form-label {
  display: block;
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2);
}

.form-input {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  color: var(--color-text);
  font-size: var(--text-base);
  transition: border-color var(--transition-fast), background var(--transition-fast);
}

.form-input:focus {
  outline: none;
  border-color: var(--color-accent);
  background: rgba(255, 255, 255, 0.08);
}

.form-input::placeholder {
  color: var(--color-text-muted);
}

textarea.form-input {
  min-height: 8rem;
  resize: vertical;
}

select.form-input {
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%2394a3b8' viewBox='0 0 16 16'%3E%3Cpath d='M8 11L3 6h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  padding-right: 2.5rem;
}

.form-hint {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-1);
}

.form-error {
  font-size: var(--text-xs);
  color: var(--color-error);
  margin-top: var(--space-1);
}


/* --------------------------------------------------------------------------
   16. Component: Buttons
   -------------------------------------------------------------------------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background var(--transition-fast), border-color var(--transition-fast);
  text-decoration: none;
  white-space: nowrap;
}

.btn--primary {
  background: var(--color-accent);
  color: #fff;
}

.btn--primary:hover {
  background: var(--color-accent-hover);
  color: #fff;
}

.btn--secondary {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--color-border);
  color: var(--color-text);
}

.btn--secondary:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: var(--color-border-hover);
  color: var(--color-text);
}

.btn--warm {
  background: var(--color-warm);
  color: #fff;
}

.btn--warm:hover {
  background: var(--color-warm-hover);
  color: #fff;
}

.btn--sm {
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-xs);
}


/* --------------------------------------------------------------------------
   17. Component: Site Footer
   -------------------------------------------------------------------------- */

.site-footer {
  background: var(--color-panel);
  backdrop-filter: blur(var(--blur-panel));
  -webkit-backdrop-filter: blur(var(--blur-panel));
  border-top: 1px solid var(--color-border);
  padding: var(--space-8) var(--space-4);
  margin-top: auto;
}

.site-footer__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-4);
}

.site-footer__copy {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.site-footer__links {
  display: flex;
  gap: var(--space-4);
}

.site-footer__link {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

.site-footer__link:hover {
  color: var(--color-accent);
}


/* --------------------------------------------------------------------------
   18. Page: Home
   -------------------------------------------------------------------------- */

.page-home__intro {
  text-align: center;
  max-width: 48rem;
  margin: 0 auto var(--space-12);
}

.page-home__title {
  font-size: var(--text-4xl);
  color: var(--color-warm);
  margin-bottom: var(--space-4);
}

.page-home__subtitle {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
}


/* --------------------------------------------------------------------------
   19. Page: Category
   -------------------------------------------------------------------------- */

.page-category__header {
  margin-bottom: var(--space-8);
}

.page-category__desc {
  color: var(--color-text-secondary);
  font-size: var(--text-lg);
  max-width: 42rem;
}


/* --------------------------------------------------------------------------
   20. Page: Topic
   -------------------------------------------------------------------------- */

.page-topic__header {
  margin-bottom: var(--space-8);
}

.page-topic__desc {
  color: var(--color-text-secondary);
  max-width: 42rem;
}


/* --------------------------------------------------------------------------
   21. Page: Observatory
   -------------------------------------------------------------------------- */

.page-observatory__filter {
  background: var(--color-card);
  backdrop-filter: blur(var(--blur-card));
  -webkit-backdrop-filter: blur(var(--blur-card));
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  margin-bottom: var(--space-6);
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  align-items: flex-end;
}


/* --------------------------------------------------------------------------
   22. Utilities
   -------------------------------------------------------------------------- */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

.text-center  { text-align: center; }
.text-right   { text-align: right; }
.text-muted   { color: var(--color-text-muted); }
.text-accent  { color: var(--color-accent); }
.text-warm    { color: var(--color-warm); }

.mt-4  { margin-top: var(--space-4); }
.mt-6  { margin-top: var(--space-6); }
.mt-8  { margin-top: var(--space-8); }
.mb-4  { margin-bottom: var(--space-4); }
.mb-6  { margin-bottom: var(--space-6); }
.mb-8  { margin-bottom: var(--space-8); }

.flex        { display: flex; }
.flex-wrap   { flex-wrap: wrap; }
.items-center { align-items: center; }
.gap-4       { gap: var(--space-4); }


/* --------------------------------------------------------------------------
   24. Timeline Page
   -------------------------------------------------------------------------- */

.page-timeline .site-main {
  max-width: 100%;
  padding-left: var(--space-4);
  padding-right: var(--space-4);
}

.timeline-page {
  width: 100%;
  max-width: 1600px;
  margin: 0 auto;
}

.timeline-header {
  text-align: center;
  padding: var(--space-6) var(--space-4);
  margin-bottom: var(--space-4);
}

.timeline-header h1 {
  margin-bottom: var(--space-2);
}

.timeline-header p {
  color: var(--color-muted);
  font-size: var(--text-lg);
}

/* --- Filter panel --- */

.timeline-filters {
  padding: var(--space-4);
  margin-bottom: var(--space-4);
}

.timeline-filters__section {
  margin-bottom: var(--space-3);
}

.timeline-filters__section h3 {
  font-size: var(--text-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-muted);
  margin-bottom: var(--space-2);
}

.timeline-filters__actions {
  display: inline-flex;
  gap: var(--space-2);
  margin-bottom: var(--space-2);
}

.timeline-chips {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
}

.tl-chip {
  display: inline-flex;
  align-items: center;
  padding: var(--space-1) var(--space-3);
  border-radius: 999px;
  font-size: var(--text-xs);
  cursor: pointer;
  border: 1px solid rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.08);
  color: var(--color-text);
  transition: opacity 0.2s, background 0.2s;
  user-select: none;
}

.tl-chip--active {
  background: rgba(101, 146, 255, 0.25);
  border-color: var(--color-accent);
}

.tl-chip--dimmed {
  opacity: 0.35;
}

.tl-btn {
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-sm);
  font-size: var(--text-xs);
  cursor: pointer;
  border: 1px solid rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.06);
  color: var(--color-muted);
  transition: background 0.2s;
}

.tl-btn:hover {
  background: rgba(255, 255, 255, 0.12);
}

.tl-btn--sm {
  padding: 2px var(--space-2);
  font-size: 0.65rem;
}

/* --- Time range slider --- */

.timeline-range {
  display: flex;
  gap: var(--space-6);
  align-items: center;
  flex-wrap: wrap;
}

.timeline-range label {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-muted);
}

.timeline-range input[type="range"] {
  width: 200px;
  accent-color: var(--color-accent);
}

.timeline-range span {
  min-width: 60px;
  font-variant-numeric: tabular-nums;
  font-size: var(--text-xs);
  color: var(--color-text);
}

.timeline-filters__status {
  font-size: var(--text-sm);
  color: var(--color-muted);
  margin-top: var(--space-2);
}

/* --- SVG container --- */

.timeline-container {
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  margin-bottom: var(--space-4);
  border-radius: var(--radius-md);
  background: rgba(10, 14, 26, 0.5);
  border: 1px solid rgba(255, 255, 255, 0.06);
}

#timeline-svg {
  display: block;
  min-width: 1200px;
}

/* --- SVG element styles --- */

.epoch-band {
  fill-opacity: 0.12;
}

.epoch-label {
  fill: #e2e8f0;
  font-size: 13px;
  font-weight: 600;
  text-anchor: end;
}

.epoch-time-label {
  fill: #64748b;
  font-size: 10px;
  text-anchor: end;
}

.stripe-label {
  fill: #94a3b8;
  font-size: 10px;
  text-anchor: end;
}

.stripe-bg {
  fill: rgba(255, 255, 255, 0.03);
}

.stripe-bg:nth-child(even) {
  fill: rgba(255, 255, 255, 0.06);
}

.philosophy-band {
  fill: rgba(80, 60, 120, 0.15);
}

.philosophy-label {
  fill: #94a3b8;
  font-size: 12px;
  font-weight: 600;
  text-anchor: end;
}

.axis-break path {
  stroke: #94a3b8;
  stroke-width: 1.5;
  fill: none;
}

/* --- Dots --- */

.dot {
  cursor: pointer;
  stroke: none;
  stroke-width: 0;
}

.dot:hover {
  stroke: #fff;
  stroke-width: 1.5;
}

.dot--dimmed {
  opacity: 0.08;
}

.dot--selected {
  stroke: #fff;
  stroke-width: 2;
}

.dot--philosophy {
  opacity: 0.65;
}

/* --- Connection lines --- */

.connection-line {
  stroke-width: 1;
  stroke-dasharray: 4 3;
  opacity: 0.5;
  fill: none;
}

/* --- Tooltip --- */

.tl-tooltip {
  position: fixed;
  pointer-events: none;
  z-index: 1000;
  max-width: 320px;
  padding: var(--space-2) var(--space-3);
  background: rgba(10, 14, 26, 0.92);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  font-size: var(--text-sm);
  line-height: 1.4;
}

.tl-tooltip__title {
  font-weight: 600;
  margin-bottom: 2px;
}

.tl-tooltip__year {
  color: var(--color-accent);
  font-size: var(--text-xs);
}

.tl-tooltip__tags {
  color: var(--color-muted);
  font-size: var(--text-xs);
  margin-top: 2px;
}

/* --- Detail panel --- */

.timeline-detail {
  padding: var(--space-5);
  position: relative;
  display: none;
}

.timeline-detail--open {
  display: block;
}

.timeline-detail__close {
  position: absolute;
  top: var(--space-3);
  right: var(--space-3);
  background: none;
  border: none;
  color: var(--color-muted);
  font-size: var(--text-lg);
  cursor: pointer;
  padding: var(--space-1);
  line-height: 1;
}

.timeline-detail__close:hover {
  color: var(--color-text);
}

.timeline-detail__title {
  font-size: var(--text-xl);
  font-weight: 700;
  margin-bottom: var(--space-1);
}

.timeline-detail__year {
  color: var(--color-accent);
  font-size: var(--text-sm);
  margin-bottom: var(--space-3);
}

.timeline-detail__desc {
  color: var(--color-muted);
  margin-bottom: var(--space-3);
  line-height: 1.6;
}

.timeline-detail__meta {
  display: flex;
  gap: var(--space-6);
  flex-wrap: wrap;
}

.timeline-detail__meta h4 {
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-muted);
  margin-bottom: var(--space-1);
}

.timeline-detail__tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
}

.timeline-detail__tag {
  padding: 2px var(--space-2);
  border-radius: 999px;
  font-size: var(--text-xs);
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.12);
}

.timeline-detail__link {
  display: block;
  font-size: var(--text-sm);
  color: var(--color-accent);
  margin-bottom: 2px;
}


/* --------------------------------------------------------------------------
   23. Responsive — Mobile First
   -------------------------------------------------------------------------- */

/* --- Up to 480px (small phones) --- */
@media (max-width: 480px) {
  :root {
    --text-4xl: 1.75rem;
    --text-3xl: 1.5rem;
  }

  .site-main {
    padding: var(--space-4) var(--space-3);
    padding-top: calc(var(--nav-height) + var(--space-4));
  }

  .category-grid {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }

  .observatory-detail__grid {
    grid-template-columns: 1fr;
  }
}

/* --- 481px to 768px (large phones, small tablets) --- */
@media (max-width: 768px) {
  .site-nav__links {
    display: none;
  }

  .site-nav__toggle {
    display: block;
  }

  .category-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .data-table {
    font-size: var(--text-xs);
  }

  .data-table th,
  .data-table td {
    padding: var(--space-2) var(--space-3);
  }

  .site-footer__inner {
    flex-direction: column;
    text-align: center;
  }
}

/* --- 769px to 1024px (tablets, small desktops) --- */
@media (min-width: 769px) and (max-width: 1024px) {
  .category-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-4);
  }
}

/* --- 1025px+ (desktops) --- */
@media (min-width: 1025px) {
  .category-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}