/* ============================================================
   Response Spectrum — Mohammad Talebi-Kalaleh
   Visual language matching mtalebi.github.io
   ============================================================ */

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

:root {
  --font-serif: "Crimson Pro", Garamond, Georgia, serif;
  --font-sans:  "IBM Plex Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-mono:  "IBM Plex Mono", "SF Mono", Menlo, Consolas, monospace;

  --paper:       #fbfaf6;
  --paper-deep:  #f3f1ea;
  --paper-card:  #ffffff;
  --ink:         #17181c;
  --ink-2:       #2f3138;
  --ink-3:       #56595f;
  --ink-4:       #7e8088;
  --ink-5:       #a8aab0;
  --rule-soft:   rgba(23, 24, 28, 0.11);
  --rule-faint:  rgba(23, 24, 28, 0.06);
  --accent:      #8a6536;
  --accent-soft: rgba(138, 101, 54, 0.32);
  --accent-bg:   rgba(138, 101, 54, 0.05);

  --maxw: 1180px;
  --gutter: clamp(1.25rem, 4vw, 2rem);
  --radius: 3px;
}

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

body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 15.5px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4 {
  font-family: var(--font-serif);
  font-weight: 500;
  letter-spacing: -0.005em;
  color: var(--ink);
  line-height: 1.18;
}

p { color: var(--ink-2); }
p + p { margin-top: 0.8rem; }
em { font-style: italic; color: var(--ink); font-family: var(--font-serif); font-weight: 500; }
a { color: var(--ink); border-bottom: 1px solid var(--rule-soft); transition: color 160ms, border-color 160ms; }
a:hover { color: var(--accent); border-bottom-color: var(--accent); }
small { font-size: 0.85em; color: var(--ink-4); }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 var(--gutter); }

/* ===== Header ===== */
.app-header {
  border-bottom: 1px solid var(--rule-soft);
  padding: 1.6rem 0 1.4rem;
}
.app-header__inner { display: grid; gap: 1rem; }
.app-header__back {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-4);
  border-bottom: none;
  width: max-content;
}
.app-header__back:hover { color: var(--accent); }
.app-header__back i { font-size: 0.7rem; }

.app-header__eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-4);
  margin-bottom: 0.4rem;
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
}
.app-header__eyebrow::before {
  content: "";
  width: 18px;
  height: 1px;
  background: var(--accent);
}
.app-header__title {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 500;
  letter-spacing: -0.018em;
  margin-bottom: 0.6rem;
}
.app-header__sub {
  font-family: var(--font-serif);
  font-size: clamp(1.02rem, 1.4vw, 1.15rem);
  color: var(--ink-3);
  max-width: 70ch;
  line-height: 1.55;
}

/* ===== Layout ===== */
main { padding: 2rem 0 3rem; display: grid; gap: 1.4rem; }

.panel {
  background: var(--paper-card);
  border: 1px solid var(--rule-soft);
  border-radius: var(--radius);
  padding: 1.4rem 1.5rem 1.5rem;
  position: relative;
}
.panel::before {
  content: "";
  position: absolute;
  top: -1px; left: 0;
  width: 56px; height: 1px;
  background: var(--accent);
}
.panel__head {
  display: flex;
  align-items: baseline;
  gap: 0.85rem;
  margin-bottom: 1.1rem;
}
.panel__num {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.12em;
  color: var(--accent);
  font-weight: 500;
}
.panel__title {
  font-size: 1.3rem;
  font-weight: 500;
}

/* ===== Tabs ===== */
.tabs {
  display: flex;
  border-bottom: 1px solid var(--rule-soft);
  margin-bottom: 1.1rem;
  gap: 0.4rem;
}
.tab {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  background: transparent;
  border: none;
  color: var(--ink-3);
  padding: 0.6rem 0.9rem;
  cursor: pointer;
  position: relative;
  transition: color 160ms;
}
.tab:hover { color: var(--ink); }
.tab--active { color: var(--ink); }
.tab--active::after {
  content: "";
  position: absolute;
  left: 0.4rem; right: 0.4rem; bottom: -1px;
  height: 2px;
  background: var(--accent);
}
.tab-pane { display: none; }
.tab-pane--active { display: block; }

/* ===== Controls ===== */
.control-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 0.85rem 1.2rem;
}
.ctrl { display: grid; gap: 0.3rem; }
.ctrl--inline {
  grid-template-columns: max-content 1fr max-content;
  align-items: center;
  gap: 0.7rem;
}
.ctrl__label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  color: var(--ink-3);
  text-transform: uppercase;
  font-weight: 500;
}
.ctrl__label em { color: var(--ink); font-style: italic; }
.ctrl input[type="number"],
.ctrl select {
  font-family: var(--font-mono);
  font-size: 0.92rem;
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--rule-soft);
  border-radius: 2px;
  padding: 0.5rem 0.6rem;
  transition: border-color 160ms, background 160ms;
}
.ctrl input[type="number"]:focus,
.ctrl select:focus {
  outline: none;
  border-color: var(--accent);
  background: #fff;
}
.ctrl input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
}
.value {
  font-family: var(--font-mono);
  font-size: 0.86rem;
  color: var(--ink);
}

/* ===== Chip presets ===== */
.preset-row { margin-top: 0.9rem; display: flex; gap: 0.5rem; flex-wrap: wrap; }
.chip {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  background: var(--paper);
  border: 1px solid var(--rule-soft);
  padding: 0.4rem 0.75rem;
  border-radius: 999px;
  cursor: pointer;
  color: var(--ink-2);
  transition: all 160ms;
}
.chip:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-bg);
}

/* ===== Hint ===== */
.hint {
  font-family: var(--font-serif);
  font-size: 0.96rem;
  color: var(--ink-3);
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--rule-faint);
  text-align: justify;
  text-justify: inter-word;
  hyphens: auto;
  -webkit-hyphens: auto;
}
.hint strong { color: var(--ink); font-weight: 500; }

/* ===== Upload ===== */
.upload__drop {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 1.8rem;
  border: 1px dashed var(--rule-soft);
  border-radius: var(--radius);
  background: var(--paper);
  cursor: pointer;
  transition: border-color 160ms, background 160ms;
}
.upload__drop:hover {
  border-color: var(--accent);
  background: var(--accent-bg);
}
.upload__drop i { font-size: 1.6rem; color: var(--ink-4); }
.upload__drop span {
  font-family: var(--font-mono);
  font-size: 0.86rem;
  letter-spacing: 0.05em;
  color: var(--ink-2);
}
.upload__drop small {
  font-family: var(--font-mono);
  letter-spacing: 0.03em;
}

/* ===== Actions ===== */
.actions {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  flex-wrap: wrap;
  margin-top: 1.2rem;
  padding-top: 1.1rem;
  border-top: 1px solid var(--rule-faint);
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 0.6rem 1rem;
  border: 1px solid var(--rule-soft);
  border-radius: 2px;
  background: var(--paper);
  color: var(--ink);
  cursor: pointer;
  transition: all 160ms ease;
}
.btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-bg);
}
.btn--primary {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}
.btn--primary:hover {
  background: var(--accent);
  color: var(--paper);
  border-color: var(--accent);
}
.status {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--ink-3);
  margin-left: auto;
}
.status.ok { color: var(--accent); }
.status.err { color: #a83232; }

/* ===== Plots ===== */
.plot {
  width: 100%;
  min-height: 320px;
  border: 1px solid var(--rule-soft);
  border-radius: var(--radius);
  background: var(--paper-card);
  overflow: hidden;
}
.plot--tall { min-height: 520px; }

.caption {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--ink-4);
  margin-top: 0.6rem;
  line-height: 1.5;
}
.caption em { color: var(--ink-2); font-style: italic; }

.slider-row {
  margin-bottom: 1rem;
}

/* ===== Method block ===== */
.method p {
  font-family: var(--font-serif);
  font-size: 1.02rem;
  color: var(--ink-2);
  line-height: 1.65;
  max-width: 75ch;
  text-align: justify;
  text-justify: inter-word;
  hyphens: auto;
  -webkit-hyphens: auto;
}
.method em { font-family: var(--font-serif); font-style: italic; color: var(--ink); font-weight: 500; }

/* ===== References ===== */
.ref-list {
  list-style: none;
  display: grid;
  gap: 0.7rem;
}
.ref-list li {
  font-family: var(--font-serif);
  font-size: 0.98rem;
  color: var(--ink-2);
  padding-left: 1.1rem;
  position: relative;
}
.ref-list li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--ink-5);
}
.ref-list em { font-style: italic; color: var(--ink); }

/* ===== Footer ===== */
.app-footer {
  margin-top: 2.5rem;
  padding: 1.4rem 0;
  border-top: 1px solid var(--rule-soft);
}
.app-footer .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--ink-4);
}
.app-footer a { color: var(--ink-3); border-bottom: none; }
.app-footer a:hover { color: var(--accent); }

/* ===== Responsive ===== */
@media (max-width: 720px) {
  .panel { padding: 1.1rem 1.1rem 1.2rem; }
  .control-grid { grid-template-columns: 1fr 1fr; gap: 0.7rem 0.9rem; }
  .ctrl--inline { grid-template-columns: 1fr; }
  .app-footer .container { justify-content: center; text-align: center; }
}
@media (max-width: 500px) {
  .control-grid { grid-template-columns: 1fr; }
}