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

:root {
  --bg:        #080f12;
  --surface:   #0f1a20;
  --surface2:  #162028;
  --border:    #1e2e38;
  --accent:    #2dd4bf;   /* teal — unidades */
  --accent2:   #fb923c;   /* laranja — destaque */
  --accent3:   #f05a70;   /* vermelho — erro/negativo */
  --text:      #e2e8f0;
  --text-muted:#7a8fa6;
  --font-serif:'DM Serif Display', serif;
  --font-mono: 'Space Mono', monospace;
  --font-body: 'DM Sans', sans-serif;
  --radius:    12px;
  --radius-lg: 20px;
}

html { scroll-behavior: smooth; }

/* ===== ACESSIBILIDADE ===== */
.skip-link {
  position: absolute; top: -100%; left: 0;
  background: var(--accent); color: var(--bg);
  padding: 10px 20px; font-family: var(--font-mono); font-size: .85rem; font-weight: bold;
  z-index: 9999; border-radius: 0 0 8px 0; text-decoration: none; transition: top .15s;
}
.skip-link:focus { top: 0; outline: 3px solid var(--accent2); outline-offset: 2px; }

.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border-width: 0;
}

body {
  background: var(--bg); color: var(--text);
  font-family: var(--font-body); font-size: 16px; line-height: 1.7; overflow-x: hidden;
}

/* ===== HERO ===== */
.hero {
  min-height: 100vh; display: grid; grid-template-columns: 1fr 1fr;
  align-items: center; position: relative; overflow: hidden; padding: 80px 6vw 60px; gap: 40px;
}

.hero-bg { position: absolute; inset: 0; z-index: 0; pointer-events: none; }

.grid-lines {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(45,212,191,.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(45,212,191,.06) 1px, transparent 1px);
  background-size: 60px 60px;
}

/* Animação: régua deslizando */
.ruler-track {
  position: absolute; top: 48%; left: 0; right: 0; height: 24px;
  transform: translateY(-50%);
}

.ruler {
  position: absolute; top: 0; height: 24px; width: 340px;
  background: linear-gradient(to right, transparent, rgba(45,212,191,.12), transparent);
  border-top: 1px dashed rgba(45,212,191,.4); border-bottom: 1px dashed rgba(45,212,191,.4);
  animation: rulerSlide 5s linear infinite;
}

.ruler::before {
  content: '0    10   20   30   40   50';
  position: absolute; top: 3px; left: 8px;
  font-family: 'Space Mono', monospace; font-size: 8px; color: rgba(45,212,191,.5);
  letter-spacing: 5px;
}

@keyframes rulerSlide {
  0%   { left: -340px; }
  100% { left: 100%; }
}

.hero-content { position: relative; z-index: 1; }

.hero-label {
  font-family: var(--font-mono); font-size: .75rem; letter-spacing: .15em;
  text-transform: uppercase; color: var(--accent); display: block; margin-bottom: 20px;
}

.hero-title {
  font-family: var(--font-serif); font-size: clamp(2.8rem, 6vw, 5rem);
  line-height: 1.1; color: var(--text); margin-bottom: 20px;
}
.hero-title em { color: var(--accent); font-style: italic; }

.hero-sub { color: var(--text-muted); font-size: 1.05rem; margin-bottom: 36px; max-width: 420px; }

.cta-btn {
  display: inline-block; background: var(--accent); color: var(--bg);
  font-family: var(--font-mono); font-size: .85rem; font-weight: 700;
  padding: 14px 28px; border-radius: 8px; text-decoration: none;
  transition: background .2s, transform .15s; letter-spacing: .05em;
}
.cta-btn:hover { background: #22bfad; transform: translateY(-2px); }

.hero-formula {
  position: relative; z-index: 1; display: flex; align-items: center; justify-content: center;
}
.formula-big {
  font-family: var(--font-mono); font-size: clamp(.95rem, 2.2vw, 1.5rem);
  color: var(--accent); background: var(--surface); padding: 28px 36px;
  border-radius: var(--radius-lg); border: 1px solid rgba(45,212,191,.3);
  box-shadow: 0 0 40px rgba(45,212,191,.1); text-align: left; line-height: 2.2;
}

/* ===== SUMÁRIO ===== */
.sumario {
  position: sticky; top: 0; z-index: 100; background: rgba(8,15,18,.9);
  backdrop-filter: blur(12px); border-bottom: 1px solid var(--border);
  padding: 12px 6vw;
}
.sumario-inner { display: flex; align-items: center; gap: 24px; overflow-x: auto; }
.sumario-inner::-webkit-scrollbar { display: none; }

.sumario-header { display: flex; align-items: center; gap: 16px; flex-shrink: 0; }
.sumario-logo-link { display: flex; }
.sumario-logo { height: 36px; width: auto; }

.sumario-title {
  font-family: var(--font-mono); font-size: .7rem; letter-spacing: .12em;
  text-transform: uppercase; color: var(--text-muted); flex-shrink: 0;
}

.sumario-list { display: flex; gap: 4px; list-style: none; }
.sumario-list a {
  font-family: var(--font-body); font-size: .8rem; color: var(--text-muted);
  text-decoration: none; padding: 6px 12px; border-radius: 6px; white-space: nowrap;
  transition: color .2s, background .2s;
}
.sumario-list a:hover { color: var(--accent); background: rgba(45,212,191,.1); }

/* ===== MAIN ===== */
.main { max-width: 860px; margin: 0 auto; padding: 60px 24px 100px; }

/* ===== TOPIC ===== */
.topic { padding: 60px 0 40px; border-top: 1px solid var(--border); animation: fadeUp .5s ease both; }
.topic:first-child { border-top: none; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to   { opacity: 1; transform: translateY(0); }
}

.topic-header { display: flex; align-items: baseline; gap: 20px; margin-bottom: 28px; }

.topic-num {
  font-family: var(--font-mono); font-size: 3rem; font-weight: 700;
  color: rgba(45,212,191,.16); line-height: 1; flex-shrink: 0;
}

.topic-header h2 {
  font-family: var(--font-serif); font-size: clamp(1.6rem, 3vw, 2.4rem);
  color: var(--text); line-height: 1.2;
}

.topic-body { display: flex; flex-direction: column; gap: 20px; }
.topic-body p { color: var(--text-muted); line-height: 1.75; }
.topic-body strong { color: var(--text); }
.topic-body em { color: var(--accent2); font-style: normal; font-weight: 500; }

/* ===== FORMULA BOX ===== */
.formula-box {
  background: var(--surface); border: 1px solid var(--border); border-left: 3px solid var(--accent);
  border-radius: var(--radius); padding: 18px 22px;
  display: flex; flex-direction: column; gap: 6px;
}
.formula-label { font-family: var(--font-mono); font-size: .7rem; letter-spacing: .1em; text-transform: uppercase; color: var(--text-muted); }
.formula-tex { font-family: var(--font-mono); font-size: 1.05rem; color: var(--text); }
.formula-unit { font-size: .82rem; color: var(--text-muted); }

/* ===== HIGHLIGHT BOX ===== */
.highlight-box {
  background: var(--surface2); border-radius: var(--radius); border: 1px solid var(--border);
  padding: 18px 22px; display: flex; gap: 16px; align-items: flex-start;
}
.hb-icon { font-size: 1.4rem; flex-shrink: 0; }
.highlight-box p { color: var(--text-muted); margin: 0; }

/* ===== CONCEPT CARD ===== */
.concept-card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px 24px;
}
.concept-card h4 { color: var(--text); font-size: .95rem; margin-bottom: 12px; font-family: var(--font-body); font-weight: 600; }
.concept-card ul { list-style: none; display: flex; flex-direction: column; gap: 8px; }
.concept-card li { color: var(--text-muted); padding-left: 20px; position: relative; font-size: .95rem; }
.concept-card li::before { content: '—'; position: absolute; left: 0; color: var(--accent); }

/* ===== EXAMPLE BOX ===== */
.example-box {
  background: var(--surface2); border-left: 3px solid var(--accent2);
  border-radius: var(--radius); padding: 20px 24px;
}
.example-box h4 { color: var(--accent2); font-size: .9rem; font-family: var(--font-mono); letter-spacing: .05em; text-transform: uppercase; margin-bottom: 12px; }
.example-box p { color: var(--text-muted); font-size: .95rem; }
.example-box p + p { margin-top: 6px; }
.example-box strong { color: var(--text); }

/* ===== PREFIX TABLE ===== */
.prefix-table {
  width: 100%; border-collapse: collapse; font-size: .88rem;
}
.prefix-table th {
  background: var(--surface2); color: var(--text-muted); font-family: var(--font-mono);
  font-size: .72rem; text-transform: uppercase; letter-spacing: .08em;
  padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--border);
}
.prefix-table td { padding: 8px 14px; border-bottom: 1px solid rgba(30,46,56,.6); color: var(--text-muted); }
.prefix-table tr:last-child td { border-bottom: none; }
.prefix-table .pref-sym { font-family: var(--font-mono); color: var(--accent); font-weight: bold; }
.prefix-table .pref-pow { font-family: var(--font-mono); color: var(--accent2); }
.prefix-table .pref-common { background: rgba(45,212,191,.05); }

/* ===== COMPARISON TABLE ===== */
.comp-table {
  width: 100%; border-collapse: collapse; font-size: .88rem;
}
.comp-table th {
  background: var(--surface2); color: var(--text-muted); font-family: var(--font-mono);
  font-size: .72rem; text-transform: uppercase; letter-spacing: .08em;
  padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--border);
}
.comp-table td { padding: 9px 14px; border-bottom: 1px solid rgba(30,46,56,.6); color: var(--text-muted); }
.comp-table tr:last-child td { border-bottom: none; }
.comp-table .si-val { color: var(--accent); font-family: var(--font-mono); }
.comp-table .imp-val { color: var(--accent2); font-family: var(--font-mono); }

/* ===== TIMELINE ===== */
.timeline { position: relative; padding-left: 28px; display: flex; flex-direction: column; gap: 0; }
.timeline::before {
  content: ''; position: absolute; left: 8px; top: 8px; bottom: 8px;
  width: 2px; background: linear-gradient(to bottom, var(--accent), var(--border));
}

.timeline-item { position: relative; padding: 0 0 28px 20px; }
.timeline-item::before {
  content: ''; position: absolute; left: -20px; top: 6px;
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--accent); box-shadow: 0 0 8px rgba(45,212,191,.5);
}
.timeline-item:last-child { padding-bottom: 0; }

.timeline-year { font-family: var(--font-mono); font-size: .75rem; color: var(--accent); letter-spacing: .08em; margin-bottom: 4px; }
.timeline-desc { color: var(--text-muted); font-size: .93rem; line-height: 1.6; }
.timeline-desc strong { color: var(--text); }

/* ===== CORRECT / WRONG CARDS ===== */
.notation-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }

.notation-card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 20px;
}
.notation-card.ok { border-top: 3px solid #22c55e; }
.notation-card.no { border-top: 3px solid var(--accent3); }

.notation-card h4 { font-size: .8rem; font-family: var(--font-mono); letter-spacing: .08em; text-transform: uppercase; margin-bottom: 12px; }
.notation-card.ok h4 { color: #22c55e; }
.notation-card.no h4 { color: var(--accent3); }

.notation-card ul { list-style: none; display: flex; flex-direction: column; gap: 6px; }
.notation-card li { font-family: var(--font-mono); font-size: .88rem; padding: 6px 10px; border-radius: 6px; }
.notation-card.ok li { background: rgba(34,197,94,.08); color: #86efac; }
.notation-card.no li { background: rgba(240,90,112,.08); color: #fca5a5; text-decoration: line-through; text-decoration-color: rgba(240,90,112,.5); }

/* ===== CALCULADORA DE CONVERSÃO ===== */
.conv-box {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 24px;
}
.conv-box h4 { color: var(--text); font-size: .95rem; margin-bottom: 6px; }
.conv-hint { color: var(--text-muted); font-size: .85rem; margin-bottom: 18px; }

.conv-controls { display: grid; grid-template-columns: 1fr auto 1fr; gap: 10px; align-items: end; margin-bottom: 12px; }
.conv-controls label { display: flex; flex-direction: column; gap: 4px; font-size: .8rem; font-family: var(--font-mono); color: var(--text-muted); }

.conv-select {
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  color: var(--text); font-family: var(--font-mono); font-size: .83rem;
  padding: 8px 10px; outline: none; transition: border-color .2s; width: 100%;
}
.conv-select:focus { border-color: var(--accent); }

.conv-arrow { font-size: 1.3rem; color: var(--accent); text-align: center; padding-bottom: 6px; }

.conv-row { display: flex; gap: 10px; margin-bottom: 16px; }

.conv-grandeza-row { margin-bottom: 14px; }
.conv-grandeza-row label { font-size: .8rem; font-family: var(--font-mono); color: var(--text-muted); display: flex; flex-direction: column; gap: 4px; }

.conv-input {
  flex: 1; background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  color: var(--text); font-family: var(--font-mono); font-size: 1rem;
  padding: 10px 14px; outline: none; transition: border-color .2s;
}
.conv-input:focus { border-color: var(--accent); }

.conv-btn {
  background: var(--accent); color: var(--bg); border: none; border-radius: 8px;
  font-family: var(--font-mono); font-size: .85rem; font-weight: 700;
  padding: 10px 20px; cursor: pointer; transition: background .2s; white-space: nowrap;
}
.conv-btn:hover { background: #22bfad; }

.conv-result {
  margin-top: 16px; background: var(--surface2); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px 20px; min-height: 40px;
  font-size: .9rem; line-height: 1.8;
}
.conv-res-title { font-family: var(--font-mono); font-size: .7rem; text-transform: uppercase; letter-spacing: .1em; color: var(--text-muted); margin-bottom: 8px; }
.conv-res-value { font-family: var(--font-mono); font-size: 1.15rem; color: var(--accent); margin-bottom: 14px; }
.conv-res-value strong { color: var(--text); }
.conv-divider { border: none; border-top: 1px solid var(--border); margin: 12px 0; }
.conv-method { margin-bottom: 14px; }
.conv-method-title { font-size: .8rem; color: var(--text-muted); font-weight: 600; margin-bottom: 6px; }
.conv-step { font-family: var(--font-mono); font-size: .83rem; color: var(--text-muted); padding-left: 12px; margin-bottom: 4px; }
.conv-step strong { color: var(--accent); }
.conv-error { color: var(--accent3); font-family: var(--font-mono); font-size: .85rem; }

/* ===== QUIZ ===== */
.quiz-section { margin-top: 36px; }

.quiz-title {
  font-family: var(--font-mono); font-size: .7rem; letter-spacing: .12em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 20px;
}

.question-block {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 22px 24px; margin-bottom: 16px;
}

.question-num {
  display: block; font-family: var(--font-mono); font-size: .7rem; letter-spacing: .1em;
  text-transform: uppercase; color: var(--text-muted); margin-bottom: 10px;
}

.question-text { color: var(--text); font-size: .97rem; line-height: 1.65; margin-bottom: 16px; }

.options-list { display: flex; flex-direction: column; gap: 8px; }

.option-btn {
  background: var(--surface2); border: 1px solid var(--border); border-radius: 8px;
  color: var(--text-muted); font-family: var(--font-body); font-size: .9rem;
  padding: 10px 16px; text-align: left; cursor: pointer;
  transition: border-color .2s, background .2s, color .2s; display: flex; align-items: center; gap: 10px;
}
.option-btn:hover:not(:disabled) { border-color: var(--accent); color: var(--text); background: rgba(45,212,191,.07); }
.option-btn.correct { border-color: #22c55e; background: rgba(34,197,94,.1); color: #22c55e; }
.option-btn.wrong   { border-color: var(--accent3); background: rgba(240,90,112,.1); color: var(--accent3); }
.option-btn:disabled { cursor: default; opacity: .8; }

.opt-letter {
  font-family: var(--font-mono); font-size: .75rem; font-weight: 700;
  background: var(--border); border-radius: 4px; padding: 2px 6px;
  flex-shrink: 0; color: var(--text-muted);
}

.numeric-row { display: flex; align-items: center; gap: 10px; }

.numeric-inp {
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  color: var(--text); font-family: var(--font-mono); font-size: .95rem;
  padding: 8px 12px; width: 140px; outline: none; transition: border-color .2s;
}
.numeric-inp:focus { border-color: var(--accent); }

.numeric-unit { font-family: var(--font-mono); font-size: .85rem; color: var(--text-muted); }

.submit-btn {
  background: var(--accent); color: var(--bg); border: none; border-radius: 8px;
  font-family: var(--font-mono); font-size: .8rem; font-weight: 700;
  padding: 8px 18px; cursor: pointer; transition: background .2s;
}
.submit-btn:hover:not(:disabled) { background: #22bfad; }
.submit-btn:disabled { opacity: .5; cursor: default; }

.feedback {
  margin-top: 12px; padding: 12px 16px; border-radius: 8px;
  font-size: .88rem; display: none;
}
.feedback.show { display: block; }
.feedback.correct { color: #22c55e; background: rgba(34,197,94,.1); border: 1px solid rgba(34,197,94,.3); }
.feedback.wrong   { color: var(--accent3); background: rgba(240,90,112,.1); border: 1px solid rgba(240,90,112,.3); }

/* ===== SCORE ===== */
.score-section {
  background: var(--surface); border-top: 1px solid var(--border);
  padding: 80px 24px; text-align: center;
}
.score-inner { max-width: 500px; margin: 0 auto; }
.score-inner h2 { font-family: var(--font-serif); font-size: 2rem; margin-bottom: 30px; }

.score-display {
  font-family: var(--font-mono); font-size: 4rem; font-weight: 700;
  color: var(--accent); line-height: 1; margin-bottom: 16px;
}
.score-sep { color: var(--text-muted); font-size: 2.5rem; margin: 0 8px; }
#score-total { color: var(--text-muted); font-size: 2.5rem; }
#score-msg { color: var(--text-muted); margin-bottom: 24px; font-size: .95rem; }

.reset-btn {
  background: transparent; border: 1px solid var(--border); color: var(--text-muted);
  font-family: var(--font-mono); font-size: .8rem; padding: 10px 24px;
  border-radius: 8px; cursor: pointer; transition: border-color .2s, color .2s;
}
.reset-btn:hover { border-color: var(--accent3); color: var(--accent3); }

.report-actions { margin-top: 32px; padding-top: 24px; border-top: 1px solid var(--border); }
.report-hint { font-size: .8rem; color: var(--text-muted); margin-bottom: 12px; font-family: var(--font-mono); letter-spacing: .05em; }
.report-btns { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }

.report-btn {
  background: transparent; border: 1px solid var(--border); color: var(--text-muted);
  font-family: var(--font-mono); font-size: .75rem; padding: 8px 16px;
  border-radius: 6px; cursor: pointer; transition: border-color .2s, color .2s, background .2s;
}
.report-btn:hover { border-color: var(--accent); color: var(--accent); background: rgba(45,212,191,.06); }

.report-name { margin-bottom: 20px; }

.name-input {
  display: block; width: 100%; max-width: 320px; margin: 6px auto 0;
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  color: var(--text); font-family: var(--font-body); font-size: .9rem;
  padding: 9px 14px; outline: none; transition: border-color .2s;
}
.name-input:focus { border-color: var(--accent); }

/* ===== FOOTER ===== */
.footer { padding: 24px; text-align: center; border-top: 1px solid var(--border); color: var(--text-muted); font-size: .82rem; }

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  .hero { grid-template-columns: 1fr; padding: 80px 5vw 50px; }
  .hero-formula { display: none; }
  .notation-grid { grid-template-columns: 1fr; }
  .conv-controls { grid-template-columns: 1fr; }
  .conv-arrow { display: none; }
}

@media (max-width: 500px) {
  .topic-header { flex-direction: column; gap: 6px; }
  .topic-num { font-size: 1.8rem; }
}