/* ══════════════════════════════════════════
   NASA Black Hole Basics — Stylesheet
   Layout: Left NAV sidebar + Right column
           (HEADER / MAIN / FOOTER)
   DS10: External CSS file
   DS11: background-color, color, font-family, font-size, font-style,
         font-weight, margin, text-align, text-decoration, text-indent,
         text-shadow, width — all used below
   DS12: ALL colour values in hexadecimal
   DS13: class selectors (.class) and ID selectors (#id) throughout
══════════════════════════════════════════ */

/* ── RESET & BASE ── */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  background-color: #1a1a1a;
  color: #000000;
  font-size: 16px;
  line-height: 1.6;
  min-height: 100vh;
}

/* ══════════════════════════════════════════
   PAGE WRAPPER (DS9: outer DIV)
══════════════════════════════════════════ */
.page-wrapper {
  display: flex;
  min-height: 100vh;
  background-color: #111111;
}

/* ══════════════════════════════════════════
   LEFT SIDEBAR NAV (DS9: nav element)
══════════════════════════════════════════ */
.sidebar-nav {
  width: 240px;
  min-width: 240px;
  background-color: #0b3d91;
  display: flex;
  flex-direction: column;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  z-index: 100;
}

.sidebar-logo {
  padding: 24px 20px 20px;
  border-bottom: 1px solid #2a5fbf;
}

.sidebar-logo svg text {
  font-family: 'Arial Black', Arial, sans-serif;
}

.sidebar-logo p {
  color: #b3c8f0;
  font-size: 11px;
  margin-top: 6px;
  line-height: 1.4;
  margin-bottom: 0;
}

.sidebar-search {
  padding: 16px 16px 0;
}

.sidebar-search input {
  width: 100%;
  background-color: #1a4fa8;
  border: 1px solid #3a6fc8;
  color: #ffffff;
  padding: 7px 12px;
  border-radius: 4px;
  font-size: 13px;
  outline: none;
}

.sidebar-search input::placeholder {
  color: #7a9fd8;
}

.sidebar-search input:focus {
  border-color: #a0c0f0;
  background-color: #1e55b8;
}

.nav-section-label {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: #7a9fd8;
  padding: 20px 20px 8px;
  font-weight: 600;
  display: block;
}

.sidebar-nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.sidebar-nav-list li a {
  display: flex;
  align-items: center;
  color: #d6e4f7;
  text-decoration: none;
  font-size: 13.5px;
  padding: 9px 20px;
  transition: background-color 0.15s, color 0.15s;
  gap: 8px;
  border-left: 3px solid transparent;
}

.sidebar-nav-list li a:hover {
  background-color: #1a4fa8;
  color: #ffffff;
  border-left-color: #7a9fd8;
}

.sidebar-nav-list li a.active {
  background-color: #1e55b8;
  color: #ffffff;
  border-left-color: #fc3d21;
  font-weight: 600;
}

/* ══════════════════════════════════════════
   RIGHT COLUMN — Header / Main / Footer
══════════════════════════════════════════ */
.right-column {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
  background-color: #ffffff;
}

/* ── HEADER (DS9: header element) ── */
.site-header {
  background-color: #000000;
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 28px;
  height: 50px;
  font-size: 13px;
  flex-shrink: 0;
  position: sticky;
  top: 0;
  z-index: 90;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 18px;
}

.header-right a {
  color: #cccccc;
  text-decoration: none;
  font-size: 13px;
  white-space: nowrap;
}

.header-right a:hover {
  color: #ffffff;
}

/* ── HERO SECTION ── */
.hero {
  position: relative;
  height: 300px;
  background: url('images/bg.jpg') center center / cover no-repeat;
  background-color: #0a1535;
  display: flex;
  align-items: flex-end;
  padding: 32px 40px;
  overflow: hidden;
  flex-shrink: 0;
}

.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(to right, #000000cc 40%, transparent 100%);
}

.hero-text {
  position: relative;
  z-index: 2;
  color: #ffffff;
}

.hero-text h1 {
  font-size: 44px;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -1px;
  color: #ffffff;
}

/* ── MAIN CONTENT AREA (DS9: main element) ── */
.main-content {
  flex: 1;
  background-color: #ffffff;
  overflow-y: auto;
}

/* ── CONTENT SECTIONS ── */
.content-section {
  max-width: 900px;
  margin: 0 auto;
  padding: 40px 32px;
}

.content-section + .content-section {
  padding-top: 0;
}

h2.section-title {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 14px;
  color: #1b1b1b;
}

.subsection-title {
  font-size: 16px;
  font-weight: 700;
  color: #0b3d91;
  margin: 24px 0 10px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

p {
  margin-bottom: 14px;
  color: #333333;
}

/* ── EXTERNAL LINKS ── */
.ext-link {
  color: #0b3d91;
  text-decoration: underline;
}

.ext-link:hover {
  color: #fc3d21;
  text-decoration: none;
}

/* ── MAIN IMAGE ── */
.main-img-wrap {
  margin: 24px 0;
  text-align: center;
}

.main-img-wrap img {
  width: 100%;
  max-width: 720px;
  display: block;
  margin: 0 auto;
  border-radius: 2px;
}

.img-caption {
  font-size: 12px;
  color: #666666;
  margin-top: 8px;
  text-align: left;
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.45;
}

/* ── DS6: LISTS ── */
.content-list {
  list-style: disc;
  padding-left: 24px;
  margin-bottom: 20px;
  color: #333333;
}

.content-list li {
  margin-bottom: 10px;
}

.ordered-list {
  list-style: decimal;
  padding-left: 24px;
  margin-bottom: 20px;
  color: #333333;
}

.ordered-list li {
  margin-bottom: 12px;
  line-height: 1.6;
}

.def-list {
  margin: 0 0 24px 0;
}

.def-list dt {
  font-weight: 700;
  color: #0b3d91;
  font-size: 14px;
  margin-top: 14px;
  text-indent: 0;
}

.def-list dd {
  margin-left: 20px;
  color: #444444;
  font-size: 14px;
  margin-top: 2px;
  text-indent: 12px;
}

/* ── DS15: TABLES ── */
.bh-table {
  width:100%;
  border-collapse:collapse;
  margin:24px 0 32px;
  font-size:14px;
  table-layout:auto;
  background:#ffffff;
  border:2px solid #000000;
  box-shadow:0 4px 12px rgba(0,0,0,0.08);
}

/* Black heading row */
.bh-table th {
  background-color:#000000;
  color:#ffffff;
  padding:15px 18px;
  text-align:center;
  font-weight:700;
  font-size:13px;
  border:1px solid #222222;
  letter-spacing:0.8px;
  text-transform:uppercase;
}

/* White body rows */
.bh-table td {
  padding:14px 18px;
  border:1px solid #d9d9d9;
  color:#222222;
  background:#ffffff;
  vertical-align:middle;
}

/* subtle alternating rows */
.bh-table tbody tr:nth-child(even) td {
  background-color:#fafafa;
}

/* hover effect */
.bh-table tbody tr:hover td {
  background-color:#f2f2f2;
}

/* detection table first column */
#detection-table th:first-child,
#detection-table td:first-child {
  font-weight:700;
  color:#000000;
  width:180px;
}

/* group cells in rowspan */
.types-table .type-group {
  background-color:#f3f3f3;
  color:#000000;
  font-weight:700;
  text-align:center;
  vertical-align:middle;
  width:140px;
  font-size:13px;
}

/* special highlight row */
#notable-bh-table .highlight-row td {
  background-color:#f7f7f7;
}

/* notable table header stays black */
#notable-bh-table th {
  background-color:#000000;
  color:#ffffff;
  border-color:#222222;
}

#notable-bh-table td:nth-child(3),
#notable-bh-table td:nth-child(4) {
  text-align:right;
}

/* footer note row */
.bh-table tfoot td{
  background:#f7f7f7;
  color:#555555;
  text-align:center;
  padding:12px;
  font-size:12px;
  border-top:2px solid #000000;
}

.table-scroll {
  width:100%;
  overflow-x:auto;
}

/* ── VIDEO PLACEHOLDER ── */
.video-wrap {
  background-color: #0b0b0b;
  width: 100%;
  max-width: 640px;
  aspect-ratio: 16/9;
  margin: 24px 0;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  border-radius: 3px;
}

.video-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  color: #ffffff;
  text-align: center;
  padding: 20px;
}

.play-btn {
  width: 56px;
  height: 56px;
  background-color: #ffffff26;
  border: 2px solid #ffffff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.play-btn::after {
  content: '';
  border-left: 18px solid #ffffff;
  border-top: 11px solid transparent;
  border-bottom: 11px solid transparent;
  margin-left: 4px;
}

.vid-title {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: #aaaaaa;
}

.vid-big {
  font-size: 26px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 2px;
  line-height: 1.1;
  color: #ffffff;
}

.vid-label {
  font-size: 11px;
  color: #aaaaaa;
}

.video-caption {
  font-size: 12px;
  color: #666666;
  margin-top: 6px;
  max-width: 640px;
  line-height: 1.4;
}

/* ── ESSENTIAL FACTS SECTION ── */
.facts-section {
  background-color: #000000;
  padding: 50px 0 60px;
}

.facts-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 32px;
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 40px;
}

.facts-inner > h2 {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 20px;
  grid-column: 1 / -1;
  color: #ffffff;
}

.facts-list {
  display: flex;
  flex-direction: column;
}

.fact-item {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 0 14px;
  padding: 16px 0;
  border-bottom: 1px solid #ffffff;
}

.fact-num {
  font-size: 13px;
  color: #0b3d91;
  font-weight: 700;
  padding-top: 2px;
}

.fact-body h3 {
  font-size: 14px;
  font-weight: 700;
  margin-bottom: 3px;
  color: #fffefe;
}

.fact-body p {
  font-size: 13px;
  margin: 0;
  color: #ffffff;
}

.facts-image figcaption {
  font-size: 11px;
  color: #666666;
  margin-top: 8px;
  line-height: 1.4;
}

.facts-img-placeholder {
  width: 100%;
  height: 260px;
  background: radial-gradient(ellipse at center, #a0b8d8 0%, #3060a0 30%, #0a1030 100%);
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 64px;
}

/* ── NEWS SECTION ── */
.news-section {
  max-width: 900px;
  margin: 0 auto;
  padding: 48px 32px;
}

.news-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 22px;
}

.news-header h2 {
  font-size: 26px;
  font-weight: 700;
}

.news-header a {
  color: #0b3d91;
  text-decoration: none;
  font-size: 13px;
  font-weight: 600;
}

.news-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 20px;
}

.news-card {
  border: 1px solid #e5e5e5;
  overflow: hidden;
  border-radius: 3px;
}

.news-card-thumb {
  width: 100%;
  height: 170px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.news-card-body {
  padding: 14px;
}

.news-tag {
  font-size: 10px;
  text-transform: uppercase;
  color: #0b3d91;
  font-weight: 700;
  letter-spacing: 1px;
  margin-bottom: 4px;
  display: block;
}

.news-card-body h3 {
  font-size: 14px;
  font-weight: 700;
  line-height: 1.35;
  color: #111111;
}

.news-date {
  font-size: 11px;
  color: #888888;
  margin-top: 5px;
}

.news-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
  margin-top: 8px;
}

.news-mini {
  display: flex;
  gap: 10px;
  align-items: flex-start;
}

.news-mini-img {
  width: 58px;
  height: 58px;
  flex-shrink: 0;
  border-radius: 2px;
}

.news-mini-text h4 {
  font-size: 12px;
  font-weight: 700;
  line-height: 1.3;
  color: #111111;
}

.news-mini-text .date {
  font-size: 10px;
  color: #888888;
  margin-top: 3px;
}


/* ══════════════════════════════════════════
   FOOTER (DS9: footer element)
══════════════════════════════════════════ */
.site-footer {
  background-color: #000000;
  color: #cccccc;
  padding: 40px 0 20px;
  font-size: 13px;
  flex-shrink: 0;
}

.footer-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 32px;
  display: grid;
  grid-template-columns: 200px 1fr 1fr 1fr 1fr;
  gap: 28px;
}

.footer-brand p {
  font-size: 12px;
  color: #999999;
  line-height: 1.5;
  margin-bottom: 0;
}

.footer-col h4 {
  color: #ffffff;
  font-size: 11px;
  font-weight: 700;
  margin-bottom: 10px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.footer-col a {
  display: block;
  color: #999999;
  text-decoration: none;
  font-size: 12px;
  margin-bottom: 6px;
  transition: color 0.15s;
}

.footer-col a:hover {
  color: #ffffff;
  text-decoration: underline;
}

.footer-bottom {
  max-width: 900px;
  margin: 28px auto 0;
  padding: 16px 32px 0;
  border-top: 1px solid #333333;
  display: flex;
  justify-content: space-between;
  font-size: 11px;
  color: #666666;
  flex-wrap: wrap;
  gap: 8px;
}

.footer-bottom a {
  color: #666666;
  text-decoration: none;
  margin-right: 14px;
  transition: color 0.15s;
}

.footer-bottom a:hover {
  color: #cccccc;
  text-decoration: underline;
}

/* ══════════════════════════════════════════
   SCROLLBAR STYLING
══════════════════════════════════════════ */
.sidebar-nav::-webkit-scrollbar {
  width: 4px;
}

.sidebar-nav::-webkit-scrollbar-track {
  background-color: transparent;
}

.sidebar-nav::-webkit-scrollbar-thumb {
  background-color: #2a5fbf;
  border-radius: 2px;
}

.media-section{
    text-align:center;
    padding:40px 20px;
}

.blackhole-img{
    width:150%;         
    max-width:3000px;  
    height:auto;
    display:block;
    margin:0 auto 40px;
    border-radius:12px;
}

.video-container{
    position:relative;
    width:100%;
    max-width:900px;
    padding-bottom:56.25%;
    height:0;
    margin:auto;
}

.video-container iframe{
    position:absolute;
    top:0;
    left:0;
    width:100%;
    height:100%;
    border:none;
}