/* ============================================================
   Energjia dhe Format e Saj
   Aesthetic: physics graph-paper poster — warm paper, ink rules,
   hard offset shadows, monospace data labels, dark lab "screens".
   ============================================================ */

:root {
  --paper:   #f1ece0;   /* warm paper */
  --panel:   #fbf8f1;   /* card surface */
  --ink:     #181712;   /* near-black warm */
  --ink-2:   #3a382f;
  --muted:   #6c6759;
  --line:    rgba(24, 23, 18, 0.16);
  --grid:    rgba(24, 23, 18, 0.055);
  --screen:  #14130d;   /* dark inset for interactive labs */

  --energy:  #f5b700;   /* highlighter yellow */
  --accent:  #1f48d8;   /* per-section, default blue */

  --r: 5px;             /* base radius (small + deliberate) */
  --sh: 5px 5px 0 var(--ink);
}

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

html { scroll-behavior: smooth; background: var(--paper); }

body {
  font-family: 'Inter', system-ui, sans-serif;
  color: var(--ink);
  line-height: 1.6;
  background: transparent;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4,
.brand, .stat-num, .big-score, .footer-title {
  font-family: 'Bricolage Grotesque', 'Inter', sans-serif;
  letter-spacing: -0.02em;
}

/* monospace "data" voice */
.eyebrow, .author, .topic-num, .q-num, .units li,
.ro span, .ro b, .stat-lbl, .hint, .formula, .formula-key,
.nav-links a, .quiz-progress, .scroll-hint {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
}

/* faint moving particles — toned to ambient texture */
#bg-canvas {
  position: fixed;
  inset: 0;
  z-index: -2;
  width: 100%;
  height: 100%;
  opacity: 0.4;
}

/* graph-paper grid overlay */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 26px 26px;
}

/* ============ Scroll progress ============ */
#scroll-progress {
  position: fixed;
  top: 0; left: 0;
  height: 4px;
  width: 0%;
  background: var(--ink);
  z-index: 100;
}

/* ============ Navbar ============ */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 90;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.6rem;
  background: var(--paper);
  border-bottom: 2px solid var(--ink);
}
.brand {
  font-weight: 800;
  font-size: 1.2rem;
  text-decoration: none;
  color: var(--ink);
  display: flex; align-items: center; gap: 0.55rem;
}
.brand-dot {
  width: 13px; height: 13px;
  background: var(--energy);
  border: 2px solid var(--ink);
  border-radius: 2px;
  transform: rotate(45deg);
}
.brand-light { color: var(--accent); }

.nav-links { display: flex; gap: 0.15rem; flex-wrap: wrap; }
.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.72rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0.4rem 0.6rem;
  border: 1px solid transparent;
  border-radius: 3px;
  transition: color 0.15s, background 0.15s, border-color 0.15s;
}
.nav-links a:hover { color: var(--ink); border-color: var(--line); }
.nav-links a.active { color: var(--ink); background: var(--energy); border-color: var(--ink); }
.nav-toggle {
  display: none;
  background: none; border: 2px solid var(--ink); border-radius: 3px;
  color: var(--ink); font-size: 1.1rem; line-height: 1; padding: 0.25rem 0.5rem; cursor: pointer;
}

/* ============ Hero ============ */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 6rem 1.5rem 3rem;
  position: relative;
}
.hero-inner { max-width: 880px; animation: rise 0.8s ease both; }
.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.32em;
  font-size: 0.74rem;
  color: var(--ink);
  margin-bottom: 1.4rem;
  display: inline-block;
  padding: 0.35rem 0.7rem;
  border: 1.5px solid var(--ink);
  border-radius: 3px;
  background: var(--panel);
}
.hero-title {
  font-size: clamp(2.7rem, 8.5vw, 5.6rem);
  font-weight: 800;
  line-height: 1.0;
}
.grad {
  background: var(--energy);
  color: var(--ink);
  padding: 0 0.12em;
  margin: 0.12em 0;
  display: inline-block;
  box-shadow: 4px 4px 0 var(--ink);
  -webkit-box-decoration-break: clone;
  box-decoration-break: clone;
}
.hero-sub {
  color: var(--ink-2);
  font-size: clamp(1rem, 2.3vw, 1.2rem);
  max-width: 620px;
  margin: 1.8rem auto 2.3rem;
}
.hero-cta { display: flex; gap: 0.9rem; justify-content: center; flex-wrap: wrap; }

/* ---- Buttons: solid, bordered, hard shadow, press ---- */
.btn {
  display: inline-block;
  padding: 0.85rem 1.7rem;
  border-radius: var(--r);
  font-weight: 700;
  font-size: 0.92rem;
  text-decoration: none;
  cursor: pointer;
  border: 2px solid var(--ink);
  transition: transform 0.12s, box-shadow 0.12s;
  font-family: inherit;
}
.btn-primary { background: var(--ink); color: var(--paper); box-shadow: 5px 5px 0 var(--energy); }
.btn-ghost   { background: var(--panel); color: var(--ink); box-shadow: 5px 5px 0 var(--ink); }
.btn:hover   { transform: translate(-2px, -2px); box-shadow: 7px 7px 0 var(--ink); }
.btn-primary:hover { box-shadow: 7px 7px 0 var(--energy); }
.btn:active  { transform: translate(2px, 2px); box-shadow: 2px 2px 0 var(--ink); }

.hero-stats {
  display: flex;
  gap: 0;
  justify-content: center;
  margin-top: 3.2rem;
  flex-wrap: wrap;
  border: 2px solid var(--ink);
  border-radius: var(--r);
  overflow: hidden;
  background: var(--panel);
  width: fit-content;
  margin-left: auto;
  margin-right: auto;
  box-shadow: var(--sh);
}
.stat {
  display: flex; flex-direction: column;
  padding: 1rem 1.6rem;
  border-right: 2px solid var(--ink);
}
.stat:last-child { border-right: none; }
.stat-num { font-size: 2rem; font-weight: 800; color: var(--accent); line-height: 1; }
.stat-lbl { font-size: 0.68rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.05em; margin-top: 0.35rem; }

.scroll-hint {
  position: absolute;
  bottom: 1.5rem;
  font-size: 0.66rem;
  letter-spacing: 0.4em;
  text-transform: uppercase;
  color: var(--muted);
  animation: bob 1.8s ease-in-out infinite;
}
@keyframes bob { 0%,100% { transform: translateY(0); opacity: 0.5; } 50% { transform: translateY(7px); opacity: 1; } }
@keyframes rise { from { opacity: 0; transform: translateY(26px); } to { opacity: 1; transform: translateY(0); } }

/* ============ Topic sections ============ */
.topic {
  max-width: 1080px;
  margin: 0 auto;
  padding: 5rem 1.5rem;
  scroll-margin-top: 64px;
}
.topic[data-accent="cyan"]   { --accent: #1f48d8; }
.topic[data-accent="violet"] { --accent: #6d28d9; }
.topic[data-accent="amber"]  { --accent: #d2601a; }
.topic[data-accent="green"]  { --accent: #15803d; }
.topic[data-accent="rose"]   { --accent: #c01f6b; }

.topic-head {
  display: flex;
  align-items: flex-end;
  gap: 1.3rem;
  margin-bottom: 2.6rem;
  border-bottom: 3px solid var(--ink);
  padding-bottom: 1.2rem;
}
.topic-num {
  font-size: 2.6rem;
  font-weight: 700;
  color: var(--accent);
  min-width: 62px;
  line-height: 0.85;
}
.author {
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 0.72rem;
  color: var(--paper);
  background: var(--accent);
  padding: 0.2rem 0.55rem;
  border-radius: 3px;
  display: inline-block;
  margin-bottom: 0.55rem;
}
.topic-head h2 {
  font-size: clamp(1.4rem, 3.6vw, 2.2rem);
  font-weight: 700;
}

/* ============ Cards ============ */
.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.2rem;
  margin-bottom: 1.4rem;
}
.card {
  background: var(--panel);
  border: 2px solid var(--ink);
  border-radius: var(--r);
  padding: 1.5rem 1.6rem;
  box-shadow: 3px 3px 0 var(--ink);
  transition: transform 0.18s, box-shadow 0.18s;
}
.card:hover { transform: translate(-3px, -3px); box-shadow: 7px 7px 0 var(--accent); }
.card.wide { margin-bottom: 1.4rem; }
.card h3 { font-size: 1.2rem; margin-bottom: 0.8rem; }
.card p { color: var(--ink-2); margin-bottom: 0.7rem; }
.card p strong, .card p b { color: var(--ink); font-weight: 700; }
.card em { font-style: normal; font-weight: 700; background: var(--energy); padding: 0 0.18em; border-radius: 2px; }

.units { list-style: none; margin-top: 0.6rem; }
.units li {
  padding: 0.5rem 0;
  border-bottom: 1px dashed var(--line);
  color: var(--ink-2);
  font-size: 0.84rem;
}
.units li b { color: var(--accent); }

.formula {
  font-size: 1.4rem;
  font-weight: 700;
  text-align: center;
  padding: 1rem;
  margin: 0.9rem 0;
  background: var(--panel);
  border: 2px solid var(--ink);
  border-left: 7px solid var(--accent);
  border-radius: var(--r);
  color: var(--ink);
}
.formula.small { font-size: 1.1rem; }
.formula-key { font-size: 0.78rem; text-align: center; color: var(--muted); }
.formula-key b { color: var(--ink); }

/* ============ Highlight / law — printed pull-quote block ============ */
.highlight {
  background: var(--accent);
  color: var(--paper);
  border: 2px solid var(--ink);
  border-radius: var(--r);
  padding: 2rem;
  margin: 1.8rem 0;
  text-align: center;
  box-shadow: var(--sh);
}
.highlight h3 { font-size: 1.3rem; margin-bottom: 0.8rem; color: var(--paper); }
.highlight p { color: rgba(255,255,255,0.86); }
.big-law {
  font-family: 'Bricolage Grotesque', sans-serif;
  font-size: clamp(1.2rem, 3vw, 1.6rem) !important;
  font-weight: 700;
  color: var(--paper) !important;
  margin-bottom: 0.8rem;
  line-height: 1.3;
}
.green-h, .rose-h { background: var(--accent); }
.rose-h { text-align: left; }
.rose-h h3 { text-align: left; }

/* ============ Examples ============ */
.examples-title {
  font-size: 1.05rem;
  margin: 2.2rem 0 1.1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  display: inline-block;
  border-bottom: 3px solid var(--accent);
  padding-bottom: 0.2rem;
}
.examples {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 1rem;
}
.ex {
  background: var(--panel);
  border: 2px solid var(--ink);
  border-radius: var(--r);
  padding: 1.1rem 1.2rem;
  box-shadow: 3px 3px 0 var(--ink);
  transition: transform 0.18s, box-shadow 0.18s;
}
.ex:hover { transform: translate(-3px, -3px); box-shadow: 6px 6px 0 var(--accent); }
.ex-ico { font-size: 1.8rem; display: block; margin-bottom: 0.5rem; }
.ex b { display: block; margin-bottom: 0.3rem; }
.ex p { color: var(--ink-2); font-size: 0.86rem; }

/* ============ Lab (interactive) ============ */
.lab {
  background: var(--panel);
  border: 2px solid var(--ink);
  border-radius: var(--r);
  padding: 1.8rem;
  margin: 1.8rem 0;
  box-shadow: var(--sh);
}
.lab-head h3 { font-size: 1.25rem; margin-bottom: 0.4rem; }
.lab-head h3::before {
  content: "LAB";
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.62rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--paper);
  background: var(--accent);
  padding: 0.15rem 0.4rem;
  border-radius: 3px;
  margin-right: 0.6rem;
  vertical-align: middle;
}
.lab-head p { color: var(--ink-2); font-size: 0.9rem; margin-bottom: 1.4rem; }
.lab-body {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1.8rem;
  align-items: center;
}
.lab-controls { display: flex; flex-direction: column; gap: 1rem; }
.lab-controls label {
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted);
  font-family: 'JetBrains Mono', monospace;
}
.lab-controls label span { color: var(--accent); font-weight: 700; }

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  border-radius: 0;
  background: var(--ink);
  outline: none;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 20px; height: 20px;
  border-radius: 3px;
  background: var(--accent);
  border: 2px solid var(--ink);
  cursor: pointer;
  transition: transform 0.12s;
}
input[type="range"]::-webkit-slider-thumb:hover { transform: scale(1.15); }
input[type="range"]::-moz-range-thumb {
  width: 20px; height: 20px;
  border: 2px solid var(--ink);
  border-radius: 3px; background: var(--accent); cursor: pointer;
}

.lab-readout { display: flex; gap: 0.7rem; flex-wrap: wrap; }
.ro {
  flex: 1;
  min-width: 90px;
  background: var(--paper);
  border: 2px solid var(--ink);
  border-radius: var(--r);
  padding: 0.65rem 0.8rem;
  text-align: center;
}
.ro span { display: block; font-size: 0.62rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.06em; }
.ro b { font-size: 1.1rem; font-weight: 700; }
.ro-ep b { color: #6d28d9; }
.ro-ek b { color: #1f48d8; }
.ro-tot b { color: #15803d; }
.hint { font-size: 0.74rem; color: var(--muted); }

.lab-stage {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--screen);
  border: 2px solid var(--ink);
  border-radius: var(--r);
  padding: 1.2rem;
}
#ball-canvas {
  background: transparent;
  border-radius: 3px;
  display: block;
}

/* Heater (electric -> thermal) */
.heater { display: flex; flex-direction: column; align-items: center; gap: 1rem; }
.coil {
  width: 200px; height: 60px;
  border-radius: 4px;
  border: 2px solid #000;
  background: repeating-linear-gradient(90deg, #444 0 8px, #2a2a2a 8px 16px);
  transition: box-shadow 0.3s, background 0.3s;
}
.thermo {
  width: 28px; height: 160px;
  border-radius: 999px;
  background: rgba(255,255,255,0.1);
  border: 2px solid rgba(255,255,255,0.4);
  display: flex; align-items: flex-end;
  overflow: hidden;
  padding: 3px;
}
.thermo-fill {
  width: 100%; height: 10%;
  border-radius: 999px;
  background: linear-gradient(0deg, #34e0ff, #ff5722);
  transition: height 0.4s ease;
}

/* Solar scene */
.solar-scene {
  width: 280px; height: 240px;
  position: relative;
  display: flex;
  align-items: flex-end;
  justify-content: center;
}
.sun {
  position: absolute;
  top: 10px; left: 50%;
  transform: translateX(-50%);
  font-size: 3rem;
  transition: filter 0.3s, transform 0.3s, opacity 0.3s;
  filter: drop-shadow(0 0 30px gold);
}
.panel {
  width: 180px; height: 90px;
  background: linear-gradient(120deg, #11305a, #0a1f3c);
  border: 2px solid #2b5a99;
  border-radius: 4px;
  transform: perspective(400px) rotateX(45deg);
  position: relative;
  background-image:
    linear-gradient(90deg, transparent 32%, rgba(0,0,0,0.4) 33% 34%, transparent 35%),
    linear-gradient(90deg, transparent 65%, rgba(0,0,0,0.4) 66% 67%, transparent 68%),
    linear-gradient(0deg, transparent 48%, rgba(0,0,0,0.4) 49% 50%, transparent 51%);
}
.panel-glow {
  position: absolute; inset: 0;
  border-radius: 3px;
  background: radial-gradient(circle, rgba(245,183,0,0.7), transparent 70%);
  opacity: 0.3;
  transition: opacity 0.3s;
}

/* ============ Transform picker ============ */
.transform { margin: 1.5rem 0; }
.transform-btns {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  margin-bottom: 1.3rem;
}
.tbtn {
  background: var(--panel);
  border: 2px solid var(--ink);
  color: var(--ink);
  padding: 0.55rem 1rem;
  border-radius: var(--r);
  cursor: pointer;
  font-size: 0.88rem;
  font-weight: 600;
  font-family: inherit;
  transition: transform 0.12s, box-shadow 0.12s, background 0.12s, color 0.12s;
  box-shadow: 2px 2px 0 var(--ink);
}
.tbtn:hover { transform: translate(-2px, -2px); box-shadow: 4px 4px 0 var(--ink); }
.tbtn.active { background: var(--accent); color: var(--paper); box-shadow: 2px 2px 0 var(--ink); }
.transform-display {
  background: var(--panel);
  border: 2px solid var(--ink);
  border-radius: var(--r);
  padding: 2rem;
  min-height: 200px;
  box-shadow: var(--sh);
  animation: fade 0.35s ease;
}
.transform-display h4 { font-size: 1.3rem; margin-bottom: 0.4rem; }
.transform-display .desc { color: var(--ink-2); margin-bottom: 1.5rem; }
@keyframes fade { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }

.flow {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.55rem;
  margin-top: 1.2rem;
  justify-content: center;
}
.flow-step {
  background: var(--paper);
  border: 2px solid var(--ink);
  border-radius: var(--r);
  padding: 0.6rem 0.9rem;
  font-weight: 600;
  font-size: 0.88rem;
}
.arr { color: var(--accent); font-size: 1.3rem; font-weight: 800; }

.why-list { list-style: none; margin-top: 0.5rem; }
.why-list li { color: rgba(255,255,255,0.9); padding: 0.4rem 0; }

/* ============ Quiz ============ */
.quiz {
  background: var(--panel);
  border: 2px solid var(--ink);
  border-radius: var(--r);
  padding: 2rem;
  box-shadow: var(--sh);
}
.quiz-progress {
  text-align: right;
  color: var(--muted);
  font-weight: 700;
  margin-bottom: 1rem;
  font-size: 0.85rem;
}
.quiz-progress span { color: var(--accent); }
.q-card { animation: fade 0.35s ease; }
.q-num { color: var(--accent); font-weight: 700; font-size: 0.74rem; letter-spacing: 0.14em; }
.q-text { font-size: 1.25rem; font-weight: 700; font-family: 'Bricolage Grotesque', sans-serif; margin: 0.5rem 0 1.3rem; }
.q-options { display: grid; gap: 0.7rem; }
.q-opt {
  background: var(--paper);
  border: 2px solid var(--ink);
  color: var(--ink);
  padding: 0.85rem 1.1rem;
  border-radius: var(--r);
  text-align: left;
  cursor: pointer;
  font-size: 0.94rem;
  font-family: inherit;
  font-weight: 500;
  transition: transform 0.12s, box-shadow 0.12s;
  box-shadow: 2px 2px 0 var(--ink);
}
.q-opt:hover:not(:disabled) { transform: translate(-2px, -2px); box-shadow: 4px 4px 0 var(--ink); }
.q-opt:disabled { cursor: default; }
.q-opt.correct { background: #15803d; border-color: var(--ink); color: #fff; box-shadow: 2px 2px 0 var(--ink); }
.q-opt.wrong   { background: #c01f6b; border-color: var(--ink); color: #fff; box-shadow: 2px 2px 0 var(--ink); }
.q-feedback {
  margin-top: 1.1rem;
  padding: 0.9rem 1.1rem;
  border-radius: var(--r);
  background: var(--paper);
  border: 2px solid var(--ink);
  color: var(--ink-2);
  font-size: 0.9rem;
  animation: fade 0.3s;
}
.q-next {
  margin-top: 1.2rem;
  background: var(--ink);
  color: var(--paper);
  border: 2px solid var(--ink);
  padding: 0.7rem 1.5rem;
  border-radius: var(--r);
  font-weight: 700;
  cursor: pointer;
  font-family: inherit;
  box-shadow: 4px 4px 0 var(--energy);
  transition: transform 0.12s, box-shadow 0.12s;
}
.q-next:hover { transform: translate(-2px, -2px); box-shadow: 6px 6px 0 var(--energy); }
.q-next:active { transform: translate(2px, 2px); box-shadow: 1px 1px 0 var(--energy); }
.quiz-result { text-align: center; animation: fade 0.45s; }
.quiz-result .big-score { font-size: 4rem; font-weight: 800; color: var(--accent); line-height: 1; }
.quiz-result p { color: var(--ink-2); margin: 0.6rem 0 1.4rem; }

/* ============ Footer — dark ink bookend ============ */
.footer {
  text-align: center;
  padding: 4rem 1.5rem 3rem;
  margin-top: 4rem;
  background: var(--ink);
  color: rgba(255,255,255,0.7);
  border-top: 4px solid var(--energy);
}
.footer-title { font-size: 1.6rem; font-weight: 800; color: #fff; margin-bottom: 0.4rem; }
.authors {
  margin-top: 0.9rem;
  color: var(--energy);
  font-weight: 700;
  letter-spacing: 0.06em;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.9rem;
}
.copy { margin-top: 1.2rem; opacity: 0.75; }

/* ============ Reveal ============ */
.reveal { opacity: 0; transform: translateY(26px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.in { opacity: 1; transform: translateY(0); }

/* ============ Responsive ============ */
@media (max-width: 760px) {
  .nav-links {
    position: fixed;
    top: 52px; right: 0;
    flex-direction: column;
    background: var(--paper);
    padding: 1rem;
    border-left: 2px solid var(--ink);
    border-bottom: 2px solid var(--ink);
    border-radius: 0 0 0 var(--r);
    transform: translateX(110%);
    transition: transform 0.3s;
  }
  .nav-links.open { transform: translateX(0); }
  .nav-toggle { display: block; }
  .grid-2 { grid-template-columns: 1fr; }
  .lab-body { grid-template-columns: 1fr; }
  .lab-stage { order: -1; }
  .stat { border-right: none; border-bottom: 2px solid var(--ink); }
  .stat:last-child { border-bottom: none; }
}