:root {
  --bg: #0f172a;
  --card: #111827;
  --text: #e5e7eb;
  --accent: #38bdf8;
  --muted: #9ca3af;
  --border: rgba(56,189,248,.45);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

header {
  padding: 2rem;
  text-align: center;
  background: linear-gradient(135deg, #020617, #020617);
}

header h1 { margin-bottom: 0.3rem; }

nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem;
  padding: 1rem;
  background: #020617;
  position: sticky;
  top: 0;
  z-index: 10;
}

nav button {
  background: transparent;
  border: 1px solid var(--accent);
  color: var(--accent);
  padding: 0.4rem 0.8rem;
  cursor: pointer;
  border-radius: 6px;
}

nav button:hover {
  background: var(--accent);
  color: #020617;
}

/* Toolbar: search + downloads */
.toolbar {
  max-width: 900px;
  margin: 0.8rem auto 0;
  padding: 0 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  align-items: center;
  justify-content: space-between;
}

.search {
  flex: 1 1 240px;
  min-width: 200px;
  border: 1px solid rgba(255,255,255,.12);
  background: rgba(2,6,23,.55);
  color: var(--text);
  padding: 0.55rem 0.7rem;
  border-radius: 10px;
  outline: none;
}

.search:focus { border-color: var(--border); }

.dl {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: flex-end;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  text-decoration: none;
  color: var(--text);
  border: 1px solid rgba(255,255,255,.12);
  background: rgba(2,6,23,.55);
  padding: 0.45rem 0.75rem;
  border-radius: 10px;
  cursor: pointer;
}

.btn:hover { border-color: var(--border); background: rgba(56,189,248,.12); }
.btn.primary { border-color: var(--border); color: var(--accent); }

main {
  max-width: 900px;
  margin: auto;
  padding: 2rem;
}

section {
  background: var(--card);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  border-radius: 12px;
}

h2 { color: var(--accent); }

.muted { color: var(--muted); }

.formula {
  background: #020617;
  padding: 0.8rem;
  border-radius: 8px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Courier New", monospace;
  margin: 0.8rem 0;
  overflow-x: auto;
  position: relative;
  border: 1px solid rgba(255,255,255,.08);
}

.formula code { white-space: nowrap; }

.formula.highlight {
  border: 1px solid var(--accent);
}

.copy {
  position: absolute;
  top: 10px;
  right: 10px;
  background: rgba(56,189,248,.14);
  border: 1px solid rgba(56,189,248,.40);
  color: var(--accent);
  padding: 0.25rem 0.5rem;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.8rem;
}
.copy:hover { background: rgba(56,189,248,.22); }

.note {
  color: var(--muted);
  font-style: italic;
}

/* Figures gallery */
.gallery {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.9rem;
}

.figure {
  margin: 0;
  border: 1px solid rgba(255,255,255,.10);
  border-radius: 12px;
  overflow: hidden;
  background: rgba(2,6,23,.40);
}

.figure img {
  width: 100%;
  display: block;
}

.figure figcaption {
  padding: 0.6rem 0.8rem;
  color: var(--muted);
  font-size: 0.92rem;
}

footer {
  text-align: center;
  padding: 1rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.hide { display: none !important; }


/* ===== Header with School Logo ===== */

.site-header {
  padding: 2.2rem 1rem 1.8rem;
  background: linear-gradient(135deg, #020617, #020617);
  text-align: center;
}

.header-inner {
  max-width: 900px;
  margin: 0 auto;
}

.school-logo {
  display: block;
  margin: 0 auto 1rem;
  max-height: 200px;      /* adjust if needed */
  width: auto;
  filter: drop-shadow(0 4px 10px rgba(0,0,0,0.45));
}

.site-header h1 {
  margin-bottom: 0.3rem;
}

.site-header p {
  color: var(--muted);
  margin-top: 0.2rem;
}


/* ===== Profile Photo ===== */
.profile-photo {
  display: block;
  margin: 0.5rem auto 0.8rem;
  width: 225px;
  height: 225px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid var(--border);
  box-shadow: 0 6px 18px rgba(0,0,0,0.45);
}

/* ===== Contact Links ===== */
.contact-links {
  display: flex;
  justify-content: center;
  gap: 0.8rem;
  margin-top: 0.6rem;
  flex-wrap: wrap;
}

.contact-links a {
  color: var(--accent);
  text-decoration: none;
  border: 1px solid rgba(56,189,248,.35);
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  font-size: 0.9rem;
  background: rgba(56,189,248,.08);
}

.contact-links a:hover {
  background: rgba(56,189,248,.18);
}


/* ===== Predictor Widget ===== */
.predictor {
  margin-top: 0.8rem;
  border: 1px solid rgba(255,255,255,.10);
  border-radius: 14px;
  padding: 1rem;
  background: rgba(2,6,23,.35);
}

.predictor label {
  display: block;
  margin-bottom: 0.45rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.predict-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  align-items: center;
}

.predict-row input {
  flex: 1 1 220px;
  min-width: 200px;
  border: 1px solid rgba(255,255,255,.12);
  background: rgba(2,6,23,.55);
  color: var(--text);
  padding: 0.55rem 0.7rem;
  border-radius: 10px;
  outline: none;
}

.predict-row input:focus {
  border-color: var(--border);
}

.result {
  margin-top: 0.9rem;
  border: 1px solid rgba(56,189,248,.22);
  background: rgba(56,189,248,.06);
  border-radius: 14px;
  padding: 0.85rem 0.9rem;
}

.result-title {
  color: var(--muted);
  font-size: 0.92rem;
}

.result-value {
  font-size: 1.6rem;
  margin-top: 0.25rem;
  color: var(--accent);
  font-weight: 700;
}

.result-note {
  margin-top: 0.25rem;
  font-size: 0.9rem;
}