/* =========================
   VARIABLES Y TEMAS
========================= */
:root {
  --light-bg: #f4f6fb;
  --light-fg: #1f2937;
  --light-card: #ffffff;
  --light-border: #e5e7eb;
  --light-accent: #2563eb;

  --dark-bg: #0f172a;
  --dark-fg: #e5e7eb;
  --dark-card: #1e293b;
  --dark-border: #334155;
  --dark-accent: #38bdf8;

  --radius: 14px;
  --radius-sm: 10px;
  --transition: 0.25s ease;
  --shadow-sm: 0 4px 12px rgba(0,0,0,0.12);
  --shadow-lg: 0 10px 30px rgba(0,0,0,0.25);
}

/* =========================
   BASE
========================= */
*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  background: var(--dark-bg);
  color: var(--dark-fg);
  transition: background var(--transition), color var(--transition);
}

body.light {
  background: var(--light-bg);
  color: var(--light-fg);
}

/* =========================
   HEADER
========================= */
header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 1.5rem;
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(10px);
}

body.dark header {
  background: rgba(15, 23, 42, 0.85);
  border-bottom: 1px solid var(--dark-border);
}

body.light header {
  background: rgba(244, 246, 251, 0.85);
  border-bottom: 1px solid var(--light-border);
}

h1 {
  font-size: 1.4rem;
  font-weight: 600;
  margin: 0;
  white-space: nowrap;
}

header > div {
  display: flex;
  gap: 0.6rem;
  align-items: center;
  flex-wrap: wrap;
}

/* =========================
   BOTONES
========================= */
button,
.download summary {
  cursor: pointer;
  padding: 0.55rem 0.9rem;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  border: none;
  background: transparent;
  transition: background var(--transition),
              color var(--transition),
              transform var(--transition),
              box-shadow var(--transition);
}

button:hover,
.download summary:hover {
  transform: translateY(-1px);
}

body.dark button,
body.dark .download summary {
  background: var(--dark-card);
  color: var(--dark-fg);
}

body.dark button:hover,
body.dark .download summary:hover {
  background: var(--dark-accent);
  color: #fff;
  box-shadow: var(--shadow-sm);
}

body.light button,
body.light .download summary {
  background: var(--light-card);
  color: var(--light-fg);
  border: 1px solid var(--light-border);
}

body.light button:hover,
body.light .download summary:hover {
  background: var(--light-accent);
  color: #fff;
  box-shadow: var(--shadow-sm);
}

/* =========================
   DOWNLOAD MENU
========================= */
.download {
  position: relative;
}

.download summary {
  list-style: none;
}

.download[open] ul {
  position: absolute;
  top: 115%;
  right: 0;
  min-width: 180px;
  padding: 0.3rem 0;
  margin: 0;
  list-style: none;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

body.dark .download[open] ul {
  background: var(--dark-card);
}

body.light .download[open] ul {
  background: var(--light-card);
  border: 1px solid var(--light-border);
}

.download[open] ul li a {
  display: block;
  padding: 0.6rem 1rem;
  font-size: 0.85rem;
  text-decoration: none;
  transition: background var(--transition), color var(--transition);
}

body.dark .download[open] ul li a {
  color: var(--dark-fg);
}

body.dark .download[open] ul li a:hover {
  background: var(--dark-accent);
  color: #fff;
}

body.light .download[open] ul li a {
  color: var(--light-fg);
}

body.light .download[open] ul li a:hover {
  background: var(--light-accent);
  color: #fff;
}

/* =========================
   MAIN LAYOUT
========================= */
main {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.2rem;
  width: min(1300px, 95%);
  margin: 0 auto;
  padding: 1.5rem 0;

  /* 🔥 CENTRADO VERTICAL */
  min-height: calc(100vh - 80px);
  align-items: center;
}

/* =========================
   EDITOR
========================= */
textarea {
  width: 100%;
  min-height: 70vh;
  resize: vertical;
  font-family: "JetBrains Mono", monospace;
  font-size: 0.9rem;
  padding: 1rem;
  border-radius: var(--radius);
  border: none;
  outline: none;
  box-shadow: var(--shadow-sm);
  line-height: 1.5;
}

body.dark textarea {
  background: var(--dark-card);
  color: var(--dark-fg);
}

body.light textarea {
  background: var(--light-card);
  color: var(--light-fg);
  border: 1px solid var(--light-border);
}

/* =========================
   PREVIEW
========================= */
iframe {
  width: 100%;
  min-height: 70vh;
  border-radius: var(--radius);
  border: none;
  background: #fff;
  box-shadow: var(--shadow-sm);
}

/* =========================
   RESPONSIVE
========================= */
@media (max-width: 900px) {
  main {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  textarea,
  iframe {
    min-height: 60vh;
  }
}

@media (max-width: 600px) {
  header {
    flex-direction: column;
    align-items: stretch;
  }

  header > div {
    justify-content: space-between;
  }

  h1 {
    text-align: center;
  }

  button,
  .download summary {
    flex: 1;
    text-align: center;
  }

  textarea,
  iframe {
    min-height: 55vh;
  }
}