/* ============================================
   TAREA JAVASCRIPT — Estilos compartidos
   Estética: dark-industrial con acentos neón
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Space+Mono:ital,wght@0,400;0,700;1,400&family=Syne:wght@400;600;700;800&display=swap');

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

:root {
  --bg: #0d0d0f;
  --surface: #141418;
  --surface2: #1c1c22;
  --border: #2a2a35;
  --text: #e8e8f0;
  --muted: #6b6b80;
  --accent: #f97316;
  --font-display: 'Syne', sans-serif;
  --font-mono: 'Space Mono', monospace;
  --radius: 12px;
}

html { font-size: 16px; scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-mono);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

/* ---- GRID BACKGROUND ---- */
.bg-grid {
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
  background-image:
    linear-gradient(rgba(255,255,255,.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.02) 1px, transparent 1px);
  background-size: 40px 40px;
}

/* ---- HEADER ---- */
header {
  position: relative; z-index: 1;
  padding: 3rem 2rem 2rem;
  border-bottom: 1px solid var(--border);
}
.header-inner { max-width: 900px; margin: 0 auto; }

.tag {
  display: inline-block;
  background: var(--accent);
  color: #000;
  font-family: var(--font-mono);
  font-size: .65rem;
  font-weight: 700;
  letter-spacing: .15em;
  padding: .2em .6em;
  border-radius: 3px;
  margin-bottom: 1rem;
}

header h1 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 6vw, 3.5rem);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -.02em;
}
header h1 em { font-style: normal; color: var(--accent); }

.subtitle {
  margin-top: .5rem;
  color: var(--muted);
  font-size: .85rem;
  letter-spacing: .05em;
}

/* ---- BACK LINK ---- */
.back {
  display: inline-flex; align-items: center; gap: .4rem;
  color: var(--muted);
  font-size: .8rem;
  text-decoration: none;
  margin-bottom: 2rem;
  transition: color .2s;
}
.back:hover { color: var(--text); }

/* ---- MAIN ---- */
main {
  position: relative; z-index: 1;
  flex: 1;
  padding: 3rem 2rem;
  max-width: 900px;
  margin: 0 auto;
  width: 100%;
}

/* ---- INDEX CARDS ---- */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
}

.card {
  display: flex; flex-direction: column; gap: .6rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.8rem;
  text-decoration: none;
  color: var(--text);
  position: relative;
  overflow: hidden;
  transition: border-color .25s, transform .25s, box-shadow .25s;
}
.card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: var(--accent);
  transform: scaleX(0); transform-origin: left;
  transition: transform .3s ease;
}
.card:hover { transform: translateY(-4px); border-color: var(--accent); box-shadow: 0 12px 40px rgba(0,0,0,.4); }
.card:hover::before { transform: scaleX(1); }

.card-number {
  font-size: .65rem; font-weight: 700; color: var(--accent);
  letter-spacing: .15em; font-family: var(--font-mono);
}
.card-icon { font-size: 2rem; margin: .3rem 0; }
.card h2 { font-family: var(--font-display); font-size: 1.2rem; font-weight: 700; }
.card p { font-size: .8rem; color: var(--muted); line-height: 1.6; flex: 1; }
.card-link { font-size: .75rem; color: var(--accent); margin-top: .5rem; }

/* ---- EXERCISE PAGE LAYOUT ---- */
.exercise-header {
  display: flex; flex-direction: column; gap: .4rem;
  margin-bottom: 2rem;
}
.exercise-num {
  font-size: .65rem; font-weight: 700; color: var(--accent);
  letter-spacing: .15em;
}
.exercise-header h1 {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 800;
  letter-spacing: -.02em;
}
.exercise-header p { color: var(--muted); font-size: .82rem; line-height: 1.6; max-width: 520px; }

/* ---- FORM WIDGET ---- */
.widget {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  display: flex; flex-direction: column; gap: 1.4rem;
}

.field { display: flex; flex-direction: column; gap: .5rem; }
.field label { font-size: .72rem; letter-spacing: .1em; color: var(--muted); text-transform: uppercase; }

input[type="number"], input[type="text"], select {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-family: var(--font-mono);
  font-size: .9rem;
  padding: .7rem 1rem;
  width: 100%;
  transition: border-color .2s;
  -webkit-appearance: none;
}
input:focus, select:focus { outline: none; border-color: var(--accent); }
select option { background: var(--surface2); }

.btn {
  background: var(--accent);
  color: #000;
  font-family: var(--font-display);
  font-size: .9rem;
  font-weight: 700;
  border: none;
  border-radius: 8px;
  padding: .85rem 1.5rem;
  cursor: pointer;
  transition: opacity .2s, transform .15s;
  letter-spacing: .02em;
  align-self: flex-start;
}
.btn:hover { opacity: .88; transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

/* ---- RESULT ---- */
.result {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 1.4rem 1.6rem;
  font-size: .88rem;
  line-height: 1.8;
  display: none;
}
.result.show { display: block; animation: fadeIn .3s ease; }
.result .highlight { color: var(--accent); font-weight: 700; font-size: 1.1rem; }
.result .label { color: var(--muted); font-size: .75rem; text-transform: uppercase; letter-spacing: .08em; }

@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

/* ---- STATS TABLE ---- */
.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: .5rem;
}
.stat-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem 1.2rem;
}
.stat-box .label { color: var(--muted); font-size: .7rem; text-transform: uppercase; letter-spacing: .1em; margin-bottom: .3rem; }
.stat-box .value { color: var(--accent); font-size: 1.3rem; font-weight: 700; font-family: var(--font-mono); }

/* ---- DATA LIST ---- */
.data-list {
  display: flex; flex-wrap: wrap; gap: .5rem; margin-top: .3rem;
}
.data-chip {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: .25em .6em;
  font-size: .8rem;
  color: var(--muted);
}

/* ---- FOOTER ---- */
footer {
  position: relative; z-index: 1;
  border-top: 1px solid var(--border);
  padding: 1.2rem 2rem;
  text-align: center;
  color: var(--muted);
  font-size: .72rem;
  letter-spacing: .08em;
}