:root {
  --bg: #f5f7fa;
  --surface: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --primary: #0f5fa8;
  --primary-dark: #0b4e89;
  --success: #1f9d55;
  --border: #dbe3ea;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
  --radius: 14px;
  --max: 1100px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

a {
  color: var(--primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

[hidden] {
  display: none !important;
}

.wrapper {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: 24px;
}

.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.site-header .wrapper {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.logo {
  font-size: 24px;
  font-weight: 700;
  color: var(--text);
}

.nav {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
}

.nav a {
  color: var(--text);
  font-weight: 600;
}

.nav a[aria-current="page"] {
  color: var(--primary);
}

.hero {
  padding: 42px 0 20px;
}

.hero-box {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 34px;
}

.hero h1 {
  margin-top: 0;
  font-size: 36px;
  line-height: 1.2;
}

.hero p {
  color: var(--muted);
  font-size: 18px;
}

.button-row {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  margin-top: 22px;
}

.btn {
  display: inline-block;
  padding: 14px 22px;
  border-radius: 10px;
  font-weight: 700;
  border: none;
  cursor: pointer;
  text-decoration: none;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--primary-dark);
  text-decoration: none;
}

.btn-success {
  background: var(--success);
  color: #fff;
}

.btn-success:hover {
  filter: brightness(0.95);
  text-decoration: none;
}

.grid {
  display: grid;
  gap: 22px;
}

.grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.card {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
}

.card h2,
.card h3 {
  margin-top: 0;
}

.section {
  padding: 18px 0 10px;
}

.note {
  font-size: 14px;
  color: var(--muted);
}

.tool-box {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 28px;
  max-width: 700px;
  margin: 30px auto;
}

label {
  display: block;
  font-weight: 700;
  margin-top: 14px;
}

input,
select {
  width: 100%;
  padding: 12px;
  margin-top: 8px;
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 16px;
  background: #fff;
}

.resultado {
  margin-top: 20px;
  padding: 16px;
  background: #eef6ff;
  border: 1px solid #cfe0f5;
  border-radius: 10px;
  font-size: 18px;
}

.site-footer {
  margin-top: 40px;
  border-top: 1px solid var(--border);
  background: var(--surface);
}

.site-footer .wrapper {
  color: var(--muted);
  font-size: 14px;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.footer-nav {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.footer-nav a {
  color: var(--muted);
}

@media (max-width: 900px) {
  .grid-3 {
    grid-template-columns: 1fr;
  }

  .hero h1 {
    font-size: 30px;
  }

  .footer-inner {
    align-items: flex-start;
    flex-direction: column;
  }
}

.logo {
height: 75px;
width: auto;
display: block;
}

/* Scroll to top button */
.scroll-to-top {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 50px;
  height: 50px;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 50%;
  font-size: 20px;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, visibility 0.3s;
  z-index: 1000;
}

.scroll-to-top.show {
  opacity: 1;
  visibility: visible;
}

.scroll-to-top:hover {
  background: var(--primary-dark);
}

/* Scroll to top button */
.scroll-to-top {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 50px;
  height: 50px;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 50%;
  font-size: 20px;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, visibility 0.3s;
  z-index: 1000;
}

.scroll-to-top.show {
  opacity: 1;
  visibility: visible;
}

.scroll-to-top:hover {
  background: var(--primary-dark);
}