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

:root {
  --bg:        #04090f;
  --surf:      #080f1e;
  --surf2:     #0d1829;
  --surf3:     #111f36;
  --text:      #e2ecff;
  --muted:     #7090b8;
  --dim:       #3a5070;
  --accent:    #4af0c8;
  --blue:      #38bdf8;
  --red:       #f87171;
  --gold:      #fbbf24;
  --border:    rgba(255,255,255,0.06);
  --border2:   rgba(255,255,255,0.10);
  --radius:    18px;
  --font-body: "Source Serif 4", Georgia, serif;
  --font-mono: "JetBrains Mono", "Courier New", monospace;
  --font-disp: "Playfair Display", Georgia, serif;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.7;
  overflow-x: hidden;
}

body::before {
  content: "";
  position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background:
    radial-gradient(ellipse 60% 40% at 10% 5%,  rgba(56,189,248,.06) 0%, transparent 60%),
    radial-gradient(ellipse 50% 35% at 90% 8%,  rgba(248,113,113,.06) 0%, transparent 60%),
    radial-gradient(ellipse 40% 50% at 50% 95%, rgba(74,240,200,.04) 0%, transparent 55%);
}

/* ── TYPOGRAPHY UTILITIES ── */
.mono  { font-family: var(--font-mono); }
.dim   { color: var(--dim); }
em     { font-style: italic; color: var(--accent); }

/* ── HEADER ── */
.site-header {
  border-bottom: 1px solid var(--border);
  background: rgba(4,9,15,.88);
  backdrop-filter: blur(14px) saturate(1.4);
  position: sticky; top: 0; z-index: 100;
}

.header-inner {
  max-width: 1320px; margin: auto;
  padding: 20px 28px;
  display: flex; justify-content: space-between; align-items: center; gap: 24px;
  flex-wrap: wrap;
}

.header-tag {
  font-family: var(--font-mono);
  font-size: .68rem; letter-spacing: .2em; text-transform: uppercase;
  color: var(--accent); display: block; margin-bottom: 6px;
}

.site-title {
  font-family: var(--font-disp);
  font-size: clamp(1.6rem, 4vw, 2.6rem);
  font-weight: 900; letter-spacing: -1px; line-height: 1.05;
  margin-bottom: 6px;
}

.site-sub {
  color: var(--muted); font-size: .88rem; font-weight: 300;
  max-width: 560px; line-height: 1.55;
}

.header-badge {
  flex-shrink: 0;
  border: 1px solid rgba(74,240,200,.2);
  background: rgba(74,240,200,.04);
  border-radius: 14px; padding: 14px 20px;
  text-align: center;
}

.badge-eq {
  font-family: var(--font-mono);
  font-size: 1.18rem; color: var(--accent);
  font-weight: 600; display: block; margin-bottom: 4px;
}

.badge-label {
  font-size: .72rem; color: var(--muted);
  font-family: var(--font-mono); letter-spacing: .08em;
}

/* ── PAGE ── */
.page {
  max-width: 1320px; margin: auto;
  padding: 28px 28px 48px;
  display: flex; flex-direction: column; gap: 20px;
}

/* ── PANELS ── */
.panel {
  background: var(--surf);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 8px 40px rgba(0,0,0,.3);
}

.panel-label {
  font-family: var(--font-mono);
  font-size: .68rem; letter-spacing: .18em; text-transform: uppercase;
  color: var(--dim); padding: 12px 20px;
  border-bottom: 1px solid var(--border);
  background: var(--surf2);
}

/* ── TOP ROW ── */
.top-row {
  display: grid;
  grid-template-columns: 520px 1fr;
  gap: 20px; align-items: stretch;
}

/* Wave panel */
.wave-panel { display: flex; flex-direction: column; }

#waveCanvas {
  display: block; width: 100%; height: auto;
}

.wave-legend {
  display: flex; align-items: center; gap: 18px;
  padding: 10px 20px;
  background: var(--surf2);
  border-top: 1px solid var(--border);
  font-size: .8rem; color: var(--muted);
  font-family: var(--font-mono);
}

.legend-dot {
  display: inline-block; width: 10px; height: 10px;
  border-radius: 50%;
}
.legend-dot.blue { background: var(--blue); }
.legend-dot.red  { background: var(--red); }

/* Stats col */
.stats-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: auto auto auto;
  gap: 12px;
}

.stat-card {
  background: var(--surf);
  border: 1px solid var(--border);
  border-radius: 14px; padding: 16px 18px;
  display: flex; flex-direction: column; gap: 4px;
  transition: border-color .2s;
}

.stat-card:hover { border-color: var(--border2); }

.stat-card.accent { border-color: rgba(74,240,200,.25); }

.stat-label {
  font-family: var(--font-mono);
  font-size: .68rem; letter-spacing: .12em; text-transform: uppercase;
  color: var(--dim);
}

.stat-val {
  font-family: var(--font-mono);
  font-size: 1.28rem; font-weight: 600; color: var(--text);
  letter-spacing: -.02em; line-height: 1.1;
}

.stat-card.accent .stat-val { color: var(--accent); }

.stat-unit {
  font-family: var(--font-mono);
  font-size: .72rem; color: var(--muted);
}

.effect-card { grid-column: span 2; }

.effect-val {
  font-family: var(--font-disp);
  font-size: 1.6rem; font-weight: 700;
  transition: color .3s;
}

/* ── SPECTRUM ── */
.spectrum-panel {}

#specCanvas {
  display: block; width: 100%; height: auto;
}

.spectrum-footer {
  display: flex; justify-content: space-between;
  padding: 8px 20px;
  background: var(--surf2); border-top: 1px solid var(--border);
  font-family: var(--font-mono); font-size: .7rem; color: var(--dim);
}

/* ── CONTROLS ROW ── */
.controls-row {
  display: grid;
  grid-template-columns: 1.1fr .9fr;
  gap: 20px;
}

/* Control panel */
.control-panel { padding-bottom: 4px; }

.slider-block { padding: 20px 22px 12px; }

.slider-header {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 10px; font-family: var(--font-mono); font-size: .75rem;
}

.slider-readout {
  font-family: var(--font-mono); font-size: .92rem;
  color: var(--accent); font-weight: 600;
  background: rgba(74,240,200,.06);
  border: 1px solid rgba(74,240,200,.18);
  border-radius: 8px; padding: 4px 12px;
}

input[type="range"] {
  width: 100%; height: 6px;
  -webkit-appearance: none; appearance: none;
  background: var(--surf3);
  border-radius: 999px; outline: none; cursor: pointer;
  border: 1px solid var(--border);
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 20px; height: 20px;
  background: var(--accent);
  border-radius: 50%;
  box-shadow: 0 0 8px rgba(74,240,200,.6);
  cursor: pointer;
  transition: box-shadow .2s;
}

input[type="range"]::-webkit-slider-thumb:hover {
  box-shadow: 0 0 16px rgba(74,240,200,.9);
}

.slider-track-labels {
  display: flex; justify-content: space-between;
  margin-top: 8px; font-family: var(--font-mono); font-size: .7rem;
}

.blue-label { color: var(--blue); }
.red-label  { color: var(--red); }

.preset-grid {
  display: grid; grid-template-columns: repeat(3,1fr);
  gap: 8px; padding: 12px 22px 20px;
}

.preset-btn {
  font-family: var(--font-mono);
  font-size: .72rem; letter-spacing: .04em;
  background: var(--surf2);
  border: 1px solid var(--border);
  border-radius: 10px; padding: 10px 8px;
  color: var(--muted); cursor: pointer;
  transition: background .2s, border-color .2s, color .2s;
  line-height: 1.35; text-align: center;
}

.preset-btn:hover, .preset-btn.active {
  background: rgba(74,240,200,.08);
  border-color: rgba(74,240,200,.3);
  color: var(--accent);
}

/* Equation panel */
.eq-panel { padding: 0; }

.eq-block {
  padding: 16px 22px;
  border-bottom: 1px solid var(--border);
}

.eq-tag {
  font-family: var(--font-mono);
  font-size: .64rem; letter-spacing: .16em; text-transform: uppercase;
  color: var(--dim); margin-bottom: 8px;
}

.eq-math {
  font-family: var(--font-mono);
  font-size: 1.05rem; font-weight: 600; color: var(--text);
  margin-bottom: 6px; letter-spacing: .02em;
}

.eq-math sub { font-size: .72em; }

.eq-note {
  font-size: .82rem; color: var(--muted);
  font-weight: 300; line-height: 1.5;
}

.eq-live {
  padding: 16px 22px;
  background: rgba(74,240,200,.04);
}

.eq-live-label {
  font-family: var(--font-mono);
  font-size: .64rem; letter-spacing: .16em; text-transform: uppercase;
  color: var(--accent); margin-bottom: 8px;
}

.eq-live-math {
  font-family: var(--font-mono);
  font-size: .86rem; color: var(--muted); line-height: 1.6;
}

.eq-live-math strong { color: var(--accent); }

/* ── CONTEXT ── */
.context-panel { padding: 0; }

.context-grid {
  display: grid; grid-template-columns: repeat(4,1fr);
  gap: 0;
}

.context-block {
  padding: 24px 22px;
  border-right: 1px solid var(--border);
}

.context-block:last-child { border-right: none; }

.context-block h3 {
  font-family: var(--font-disp);
  font-size: 1.05rem; font-weight: 700;
  margin-bottom: 10px; color: var(--text);
}

.context-block p {
  font-size: .88rem; color: var(--muted);
  font-weight: 300; line-height: 1.7;
}

.context-block strong { color: var(--text); }

/* ── FOOTER ── */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 18px 28px;
  display: flex; justify-content: space-between; align-items: center;
  gap: 12px; flex-wrap: wrap;
  font-family: var(--font-mono); font-size: .72rem; color: var(--dim);
  max-width: 1320px; margin: auto;
}

/* ── RESPONSIVE ── */
@media (max-width: 1100px) {
  .top-row { grid-template-columns: 1fr; }
  .stats-col { grid-template-columns: repeat(3,1fr); }
  .effect-card { grid-column: auto; }
  .controls-row { grid-template-columns: 1fr; }
  .context-grid { grid-template-columns: repeat(2,1fr); }
  .context-block:nth-child(2) { border-right: none; }
  .context-block:nth-child(1),
  .context-block:nth-child(2) { border-bottom: 1px solid var(--border); }
  .preset-grid { grid-template-columns: repeat(2,1fr); }
}

@media (max-width: 700px) {
  .header-inner { flex-direction: column; align-items: flex-start; }
  .header-badge { align-self: flex-start; }
  .stats-col { grid-template-columns: 1fr 1fr; }
  .context-grid { grid-template-columns: 1fr; }
  .context-block { border-right: none; border-bottom: 1px solid var(--border); }
  .context-block:last-child { border-bottom: none; }
  .site-footer { flex-direction: column; align-items: flex-start; }
}