/* =============================================================
   1. Tokens
   ============================================================= */
:root {
  --bg: #f6f8fb;
  --surface: #ffffff;
  --ink: #12203a;
  --ink-soft: #566079;
  --accent: #2454c7;
  --accent-ink: #ffffff;
  --border: #dde3ee;
  --warn: #8a5a00;
  --warn-bg: #fff4e0;
  --error: #b3261e;
  --error-bg: #fdecea;

  --sans: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --display: "Manrope", var(--sans);

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --radius: 14px;
  --gutter: clamp(1rem, 4vw, 2rem);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1220;
    --surface: #121b2e;
    --ink: #eef2fb;
    --ink-soft: #a6b0c6;
    --accent: #6f96ff;
    --accent-ink: #071230;
    --border: #24304a;
    --warn: #ffcb80;
    --warn-bg: #2b2107;
    --error: #ff8a80;
    --error-bg: #2a1512;
  }
}

/* =============================================================
   2. Reset & base
   ============================================================= */
*, *::before, *::after { box-sizing: border-box; margin: 0; }
html { -webkit-text-size-adjust: 100%; tab-size: 2; scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: clip;
  overscroll-behavior-y: none;
}
img, svg { display: block; max-width: 100%; }
button { font: inherit; color: inherit; cursor: pointer; border: 0; background: none; }
a { color: inherit; text-decoration: none; }
p { text-wrap: pretty; }
h1, h2, h3 { font-family: var(--display); text-wrap: balance; line-height: 1.1; letter-spacing: -0.01em; }
::selection { background: var(--accent); color: var(--accent-ink); }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* =============================================================
   3. Utilities
   ============================================================= */
.container { max-width: 820px; margin: 0 auto; padding: 0 var(--gutter); }

.skip-link {
  position: fixed; top: -100px; left: 1rem;
  padding: .6rem 1rem; background: var(--surface); color: var(--ink);
  z-index: 9999; border-radius: 8px; font-weight: 600;
  box-shadow: 0 4px 16px rgba(0,0,0,.15);
}
.skip-link:focus { top: 1rem; }

/* =============================================================
   4. Header / footer
   ============================================================= */
.site-header { padding: 1.1rem 0; }
.header-row { display: flex; align-items: center; }
.brand { display: flex; align-items: center; gap: .5rem; font-family: var(--display); font-weight: 800; font-size: 1.15rem; }

.site-footer { padding: 2.5rem 0 3rem; border-top: 1px solid var(--border); margin-top: 3rem; }
.footer-row { display: flex; flex-wrap: wrap; gap: 1rem; justify-content: space-between; align-items: center; color: var(--ink-soft); font-size: .9rem; }
.footer-nav { display: flex; gap: 1.25rem; }
.footer-nav a:hover { color: var(--accent); }

/* =============================================================
   5. Hero + tool card
   ============================================================= */
.hero { padding: 1.5rem var(--gutter) 2rem; text-align: center; }
.hero h1 { font-size: clamp(1.6rem, 4vw, 2.3rem); }
.hero-sub { color: var(--ink-soft); margin-top: .6rem; font-size: 1.05rem; }

.tool-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: clamp(1.1rem, 4vw, 1.8rem);
  margin: 1.75rem auto 0;
  max-width: 560px;
  box-shadow: 0 10px 30px -18px rgba(18, 32, 58, .25);
  text-align: left;
}

.tool-noscript {
  background: var(--error-bg); color: var(--error);
  padding: .8rem 1rem; border-radius: 10px; margin-bottom: 1rem; font-size: .9rem;
}

.calc-form { display: flex; flex-direction: column; gap: .9rem; }
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: .7rem; }
.field { display: flex; flex-direction: column; gap: .35rem; min-width: 0; }
.field label { font-size: .8rem; font-weight: 600; color: var(--ink-soft); }
.field input, .field select {
  padding: .6rem .7rem; border: 1px solid var(--border); border-radius: 10px;
  background: var(--bg); color: var(--ink); font-size: 1rem; width: 100%;
  font-family: var(--sans);
}
.field input:focus, .field select:focus { border-color: var(--accent); }

.field-hint { font-size: .8rem; color: var(--ink-soft); margin-top: -.15rem; }

.months-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: .5rem;
}
.month-field { display: flex; flex-direction: column; gap: .3rem; min-width: 0; }
.month-field label {
  font-size: .72rem; font-weight: 600; color: var(--ink-soft);
  line-height: 1.2;
}
.month-field label span { font-weight: 400; text-transform: none; }
.month-field input {
  padding: .5rem .55rem; border: 1px solid var(--border); border-radius: 8px;
  background: var(--bg); color: var(--ink); font-size: .95rem; width: 100%;
  font-family: var(--sans);
}
.month-field input:focus { border-color: var(--accent); }

.warn-box {
  margin-top: 1.1rem; background: var(--warn-bg); color: var(--warn);
  padding: .8rem 1rem; border-radius: 10px; font-size: .9rem;
}

.result-box {
  margin-top: 1.2rem; padding-top: 1.1rem; border-top: 1px dashed var(--border);
}
.result-line { font-size: 1rem; }
.result-line strong { color: var(--accent); }
.tramos-list { list-style: none; margin: .7rem 0; display: grid; gap: .4rem; }
.tramos-list li { font-size: .92rem; color: var(--ink-soft); }
.tramos-list strong { color: var(--ink); }
.result-total {
  font-family: var(--display); font-weight: 800; font-size: 1.3rem;
  margin-top: .6rem;
}
.result-total strong { color: var(--accent); }

.privacy-badge, .limits-note {
  text-align: center; color: var(--ink-soft); font-size: .85rem;
  max-width: 560px; margin: .9rem auto 0;
}

/* =============================================================
   6. Ad slots
   ============================================================= */
.ad-slot {
  max-width: 820px; margin: 2rem auto; min-height: 90px;
  border: 1px dashed var(--border); border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  color: var(--ink-soft); font-size: .8rem; letter-spacing: .04em; text-transform: uppercase;
}

/* =============================================================
   7. Content sections
   ============================================================= */
.how-section, .seo-section, .faq-section { padding: 2.2rem var(--gutter); }
.how-section h2, .seo-section h2, .faq-section h2 { font-size: 1.4rem; margin-bottom: 1rem; }
.how-steps { list-style: none; display: grid; gap: .7rem; }
.how-steps li { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: .9rem 1.1rem; }

.seo-section p { color: var(--ink-soft); margin-bottom: .9rem; max-width: 68ch; }

.faq-section details { border-bottom: 1px solid var(--border); padding: .9rem 0; }
.faq-section summary { font-weight: 600; cursor: pointer; }
.faq-section p { color: var(--ink-soft); margin-top: .6rem; }

/* =============================================================
   8. Responsive
   ============================================================= */
@media (max-width: 539px) {
  .field-row { grid-template-columns: 1fr; }
  .months-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 720px) {
  .hero { padding-top: 2.5rem; }
}

/* =============================================================
   9. Reduced motion
   ============================================================= */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}