/* =========================================================
   KNOWLEDGE VAULT — SHARED ARTICLE CSS
   Clean, responsive, non-sticky article system.
   All selectors are scoped to .kva-*.
========================================================= */

.kva-page {
  width: 100%;
  box-sizing: border-box;
  padding: 18px 16px 72px;
}

.kva-article {
  width: 100%;
  max-width: 1040px;
  margin: 0 auto;
}

/* ---------------------------------------------------------
   Article hero
--------------------------------------------------------- */

.kva-hero {
  position: static !important;
  top: auto !important;
  bottom: auto !important;
  width: 100%;
  margin: 8px 0 54px;
  padding: 0;
  background: transparent;
}

.kva-hero-inner {
  position: static !important;
  max-width: 900px;
  margin: 0 auto;
  padding: 46px 28px 42px;
  border-top: 1px solid #e5e7eb;
  border-bottom: 1px solid #e5e7eb;
  text-align: center;
}

.kva-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 20px;
  padding: 7px 14px;
  border: 1px solid #dbe4ee;
  border-radius: 999px;
  background: #f8fafc;
  color: #2563eb;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .16em;
  text-transform: uppercase;
}

.kva-eyebrow::before,
.kva-eyebrow::after {
  content: "";
  width: 22px;
  height: 1px;
  background: #cbd5e1;
}

.kva-hero h1 {
  max-width: 820px;
  margin: 0 auto 18px;
  color: #14213d;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(2.5rem, 6vw, 4.4rem);
  font-weight: 500;
  line-height: 1.06;
  letter-spacing: -.025em;
}

.kva-hero-description {
  max-width: 760px;
  margin: 0 auto;
  color: #64748b;
  font-size: 17px;
  line-height: 1.85;
}

/* ---------------------------------------------------------
   Article content
--------------------------------------------------------- */

.kva-section {
  margin: 0 0 48px;
}

.kva-section h2 {
  margin: 0 0 16px;
  color: #17365d;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(1.75rem, 3vw, 2.3rem);
  line-height: 1.25;
}

.kva-section h3 {
  margin: 30px 0 12px;
  color: #17365d;
  font-size: 1.3rem;
  line-height: 1.4;
}

.kva-section p,
.kva-section li {
  color: #374151;
  font-size: 16px;
  line-height: 1.8;
}

.kva-section ul,
.kva-section ol {
  margin: 0 0 18px;
  padding-left: 25px;
}

.kva-section li {
  margin: 7px 0;
}

.kva-section strong {
  color: #1f2937;
}

/* ---------------------------------------------------------
   Information boxes
--------------------------------------------------------- */

.kva-lead,
.kva-example,
.kva-important {
  margin: 0 0 26px;
  padding: 19px 21px;
  border: 1px solid #e2e8f0;
  border-left: 4px solid #2563eb;
  border-radius: 12px;
  background: #f8fafc;
  color: #334155;
  line-height: 1.75;
}

.kva-example {
  border-left-color: #0f766e;
  background: #f0fdfa;
}

.kva-important {
  border-left-color: #d97706;
  background: #fffbeb;
}

/* ---------------------------------------------------------
   KaTeX mathematics
--------------------------------------------------------- */

.kva-math-display {
  width: 100%;
  box-sizing: border-box;
  margin: 24px 0;
  padding: 20px 18px;
  border: 1px solid #dbe4ee;
  border-radius: 14px;
  background: #f8fafc;
  color: #17365d;
  text-align: center;
  overflow-x: auto;
  overflow-y: hidden;
}

.kva-math-display .katex-display {
  margin: 0;
}

.kva-math-display .katex {
  font-size: clamp(1.15rem, 3vw, 1.55rem);
}

.kva-math-display.kva-math-left {
  text-align: left;
}

.kva-working {
  margin: 18px 0;
  padding: 18px 20px;
  border: 1px solid #e5e7eb;
  border-radius: 12px;
  background: #f8fafc;
  overflow-x: auto;
}

.kva-working .kva-math-display {
  margin: 0;
  padding: 6px 0;
  border: 0;
  background: transparent;
}

.kva-working .katex-display {
  text-align: left;
}

.kva-inline-math {
  white-space: nowrap;
}

/* ---------------------------------------------------------
   Tables
--------------------------------------------------------- */

.kva-table-wrap {
  width: 100%;
  margin: 22px 0;
  overflow-x: auto;
  border: 1px solid #e5e7eb;
  border-radius: 14px;
  background: #ffffff;
  -webkit-overflow-scrolling: touch;
}

.kva-table-wrap table {
  width: 100%;
  min-width: 620px;
  border-collapse: collapse;
}

.kva-table-wrap th,
.kva-table-wrap td {
  padding: 14px 15px;
  border-bottom: 1px solid #e5e7eb;
  text-align: left;
  vertical-align: top;
  color: #374151;
  font-size: 15px;
  line-height: 1.65;
}

.kva-table-wrap th {
  background: #f1f5f9;
  color: #17365d;
  font-weight: 800;
}

.kva-table-wrap tr:last-child td {
  border-bottom: 0;
}

/* ---------------------------------------------------------
   Numerical examples
--------------------------------------------------------- */

.kva-problem {
  margin: 28px 0;
  padding: 26px;
  border: 1px solid #e2e8f0;
  border-radius: 16px;
  background: #ffffff;
  box-shadow: 0 7px 22px rgba(15, 23, 42, .045);
}

.kva-problem h3 {
  margin-top: 0;
}

.kva-answer {
  margin-top: 20px;
  padding: 15px 17px;
  border-radius: 10px;
  background: #eff6ff;
  color: #17365d;
}

/* ---------------------------------------------------------
   Revision and checklist
--------------------------------------------------------- */

.kva-checklist {
  margin: 0;
  padding: 22px 28px;
  border-radius: 14px;
  background: #f8fafc;
}

.kva-revision {
  padding: 22px 24px;
  border: 1px solid #dbe4ee;
  border-radius: 14px;
  background: #f8fafc;
}

.kva-revision p {
  margin: 9px 0;
}

/* ---------------------------------------------------------
   FAQ
--------------------------------------------------------- */

.kva-faq details {
  margin: 12px 0;
  border: 1px solid #e2e8f0;
  border-radius: 12px;
  background: #ffffff;
  overflow: hidden;
}

.kva-faq summary {
  padding: 17px 18px;
  cursor: pointer;
  color: #17365d;
  font-weight: 800;
  line-height: 1.5;
}

.kva-faq details p {
  margin: 0;
  padding: 0 18px 18px;
}

/* ---------------------------------------------------------
   Ask a doubt
--------------------------------------------------------- */

.kva-doubt {
  margin: 58px 0 34px;
  padding: 40px 28px;
  border-radius: 20px;
  background: linear-gradient(135deg, #172554, #1e3a8a);
  color: #ffffff;
  text-align: center;
}

.kva-doubt-label {
  display: inline-block;
  color: #e8b254;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .16em;
}

.kva-doubt h2 {
  margin: 10px 0;
  color: #ffffff;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(1.9rem, 4vw, 2.7rem);
  line-height: 1.2;
}

.kva-doubt p {
  max-width: 700px;
  margin: 0 auto 22px;
  color: #dbeafe;
  font-size: 16px;
  line-height: 1.75;
}

.kva-doubt a {
  display: inline-block;
  padding: 12px 22px;
  border-radius: 10px;
  background: #ffffff;
  color: #17365d;
  font-weight: 800;
  text-decoration: none;
}

/* ---------------------------------------------------------
   Navigation and accessibility
--------------------------------------------------------- */

.kva-bottom-nav {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  padding-top: 10px;
}

.kva-bottom-nav a {
  color: #0d6efd;
  font-size: 15px;
  font-weight: 800;
  text-decoration: none;
}

.kva-bottom-nav a:hover,
.kva-doubt a:hover {
  text-decoration: underline;
}

.kva-section a {
  color: #0d6efd;
}

.kva-section a:focus-visible,
.kva-bottom-nav a:focus-visible,
.kva-doubt a:focus-visible,
.kva-faq summary:focus-visible {
  outline: 3px solid rgba(37, 99, 235, .3);
  outline-offset: 3px;
}

/* ---------------------------------------------------------
   Responsive
--------------------------------------------------------- */

@media (max-width: 700px) {
  .kva-page {
    padding: 12px 10px 52px;
  }

  .kva-hero {
    margin-bottom: 42px;
  }

  .kva-hero-inner {
    padding: 38px 15px 34px;
  }

  .kva-hero h1 {
    font-size: clamp(2.25rem, 11vw, 3.2rem);
    line-height: 1.08;
  }

  .kva-hero-description {
    font-size: 15.5px;
    line-height: 1.75;
  }

  .kva-section {
    margin-bottom: 38px;
  }

  .kva-section p,
  .kva-section li,
  .kva-doubt p {
    font-size: 15px;
  }

  .kva-problem {
    padding: 20px 17px;
  }

  .kva-table-wrap table {
    min-width: 560px;
  }

  .kva-table-wrap th,
  .kva-table-wrap td {
    padding: 12px;
    font-size: 14px;
  }

  .kva-checklist {
    padding: 18px 21px;
  }

  .kva-doubt {
    padding: 31px 20px;
  }

  .kva-bottom-nav {
    flex-direction: column;
  }
}

@media (max-width: 480px) {
  .kva-page {
    padding-left: 8px;
    padding-right: 8px;
  }

  .kva-eyebrow {
    font-size: 9.5px;
    letter-spacing: .12em;
  }

  .kva-math-display {
    padding: 16px 12px;
  }

  .kva-working {
    padding: 13px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .kva-doubt a {
    transition: none;
  }
}