/* Kelas Cerdas IPA — Panduan IPA Kelas 9 Kurikulum Merdeka
   Static, dependency-free stylesheet. Mobile-first. */

:root {
  --color-bg: #f6f7fa;
  --color-surface: #ffffff;
  --color-text: #1c2430;
  --color-text-muted: #5b6472;
  --color-primary: #14497a;
  --color-primary-dark: #0d3357;
  --color-accent: #d99a2b;
  --color-accent-dark: #b17f1f;
  --color-border: #e2e6ec;
  --color-tint: #eef3f9;
  --radius: 14px;
  --max-width: 820px;
  --wide-width: 1120px;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-heading: Georgia, "Times New Roman", "Noto Serif", serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.65;
  font-size: 17px;
  overflow-x: hidden;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-primary);
  text-decoration-thickness: 1px;
}

a:hover {
  color: var(--color-primary-dark);
}

h1, h2, h3 {
  font-family: var(--font-heading);
  font-weight: 700;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--color-primary);
  color: #fff;
  padding: 10px 16px;
  border-radius: 0 0 8px 0;
  z-index: 100;
}

.skip-link:focus {
  left: 0;
}

/* Top announcement bar */
.top-bar {
  background: var(--color-primary-dark);
  color: #d8e3f0;
  font-size: 0.78rem;
}

.top-bar .wrap {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 7px 20px;
  display: flex;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.top-bar strong {
  color: #fff;
}

/* Header */
.site-header {
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
  position: sticky;
  top: 0;
  z-index: 10;
}

.site-header .wrap {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.08rem;
  color: var(--color-text);
  text-decoration: none;
  font-family: var(--font-heading);
}

.brand svg {
  flex-shrink: 0;
}

.brand small {
  display: block;
  font-weight: 400;
  font-size: 0.68rem;
  color: var(--color-text-muted);
  font-family: var(--font-body);
  letter-spacing: 0.01em;
}

.main-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 20px;
  font-size: 0.92rem;
  min-width: 0;
}

.main-nav a {
  color: var(--color-text-muted);
  text-decoration: none;
  padding: 4px 0;
  font-weight: 600;
}

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

/* Breadcrumbs */
.breadcrumbs {
  max-width: var(--max-width);
  margin: 18px auto 0;
  padding: 0 20px;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.breadcrumbs.wide {
  max-width: var(--wide-width);
}

.breadcrumbs a {
  color: var(--color-text-muted);
  text-decoration: none;
}

.breadcrumbs a:hover {
  color: var(--color-primary);
}

.breadcrumbs ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0;
  padding: 0;
}

.breadcrumbs li:not(:last-child)::after {
  content: "/";
  margin-left: 6px;
  color: var(--color-border);
}

/* Hero (pillar homepage) */
.hero-pillar {
  background: linear-gradient(160deg, var(--color-primary-dark), var(--color-primary) 70%);
  color: #fff;
}

.hero-pillar .wrap {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 56px 20px 64px;
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
  gap: 32px;
  align-items: center;
}

.hero-pillar .wrap > div {
  min-width: 0;
}

.hero-pillar .eyebrow {
  color: var(--color-accent);
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.hero-pillar h1 {
  font-size: 2.3rem;
  line-height: 1.2;
  margin: 10px 0 14px;
}

.hero-pillar p {
  color: #dbe6f2;
  font-size: 1.06rem;
  margin: 0 0 22px;
}

.hero-pillar img {
  border-radius: var(--radius);
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.btn {
  display: inline-block;
  padding: 12px 22px;
  border-radius: 999px;
  font-weight: 700;
  text-decoration: none;
  font-size: 0.94rem;
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--color-accent);
  color: var(--color-primary-dark);
}

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

.btn-outline {
  border-color: rgba(255, 255, 255, 0.5);
  color: #fff;
}

.btn-outline:hover {
  border-color: #fff;
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

/* Stats bar */
.stats-bar {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.stats-bar .wrap {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 28px 20px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 20px;
  text-align: center;
}

.stat-num {
  font-family: var(--font-heading);
  font-size: 1.9rem;
  color: var(--color-primary);
  font-weight: 700;
  display: block;
}

.stat-label {
  font-size: 0.84rem;
  color: var(--color-text-muted);
}

/* Section wrap (wide) */
.section {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 52px 20px;
}

.section-head {
  max-width: 640px;
  margin: 0 auto 34px;
  text-align: center;
}

.section-head .eyebrow {
  color: var(--color-accent-dark);
  font-weight: 700;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.section-head h2 {
  font-size: 1.7rem;
  margin: 8px 0 10px;
}

.section-head p {
  color: var(--color-text-muted);
  margin: 0;
}

/* About split */
.about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 40px;
  align-items: center;
}

.about-split > div {
  min-width: 0;
}

.about-split img {
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
}

.about-split h2 {
  font-size: 1.6rem;
  margin-top: 0;
}

/* Bab grid (materi chapters) */
.bab-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 16px;
}

.bab-card {
  display: block;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
  text-decoration: none;
  color: var(--color-text);
  transition: transform 0.15s ease, border-color 0.15s ease, box-shadow 0.15s ease;
  position: relative;
}

.bab-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-3px);
  box-shadow: 0 10px 24px rgba(20, 73, 122, 0.1);
}

.bab-card .bab-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: var(--color-tint);
  color: var(--color-primary);
  font-weight: 700;
  font-family: var(--font-heading);
  margin-bottom: 10px;
}

.bab-card h3 {
  margin: 0 0 6px;
  font-size: 1.02rem;
}

.bab-card p {
  margin: 0;
  font-size: 0.87rem;
  color: var(--color-text-muted);
}

.bab-card .tag {
  position: absolute;
  top: 16px;
  right: 16px;
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--color-accent-dark);
  background: #fbf1dd;
  padding: 3px 9px;
  border-radius: 999px;
}

/* Article cards (news-style) */
.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 22px;
}

.article-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  text-decoration: none;
  color: var(--color-text);
  display: flex;
  flex-direction: column;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.article-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 24px rgba(20, 73, 122, 0.1);
}

.article-card img {
  width: 100%;
  aspect-ratio: 16/10;
  object-fit: cover;
}

.article-card .body {
  padding: 16px 18px 20px;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.article-card .kicker {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--color-accent-dark);
  letter-spacing: 0.03em;
  margin-bottom: 8px;
}

.article-card h3 {
  font-size: 1.08rem;
  margin: 0 0 8px;
  line-height: 1.35;
}

.article-card p {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  margin: 0 0 14px;
  flex: 1;
}

.article-card .read-more {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--color-primary);
}

/* Contributor / author cards */
.contributor-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 18px;
}

.contributor-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
  text-align: center;
  text-decoration: none;
  color: var(--color-text);
  transition: border-color 0.15s ease;
}

.contributor-card:hover {
  border-color: var(--color-primary);
}

.contributor-card .avatar-lg {
  width: 62px;
  height: 62px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-family: var(--font-heading);
  font-size: 1.2rem;
  margin: 0 auto 12px;
}

.contributor-card strong {
  display: block;
  font-size: 0.98rem;
}

.contributor-card .role {
  font-size: 0.78rem;
  color: var(--color-accent-dark);
  font-weight: 700;
  margin: 3px 0 8px;
}

.contributor-card p {
  font-size: 0.83rem;
  color: var(--color-text-muted);
  margin: 0;
}

/* Main article content */
.content-wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 20px 20px 60px;
}

.article-hero {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 30px 20px 6px;
}

.article-hero .eyebrow {
  color: var(--color-primary);
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.article-hero h1 {
  font-size: 2rem;
  line-height: 1.25;
  margin: 8px 0 12px;
}

.article-hero .lede {
  font-size: 1.06rem;
  color: var(--color-text-muted);
  margin-bottom: 0;
}

.meta-line {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  margin-top: 14px;
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

article h2 {
  font-size: 1.4rem;
  margin-top: 2.2em;
  margin-bottom: 0.6em;
  scroll-margin-top: 90px;
}

article h3 {
  font-size: 1.14rem;
  margin-top: 1.6em;
  margin-bottom: 0.5em;
  font-family: var(--font-body);
  font-weight: 700;
}

article p {
  margin: 0 0 1.1em;
}

article ul,
article ol {
  margin: 0 0 1.1em;
  padding-left: 1.3em;
}

article li {
  margin-bottom: 0.4em;
}

article table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.4em 0;
  font-size: 0.92rem;
}

article th {
  text-align: left;
  padding: 9px 8px;
  border-bottom: 2px solid var(--color-border);
}

article td {
  padding: 9px 8px;
  border-bottom: 1px solid var(--color-border);
}

/* Table of contents */
.toc {
  background: var(--color-tint);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 18px 20px;
  margin: 1.6em 0;
}

.toc strong {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-heading);
}

.toc ol {
  margin: 0;
  padding-left: 1.2em;
  columns: 2;
  font-size: 0.92rem;
}

@media (max-width: 640px) {
  .toc ol {
    columns: 1;
  }
}

/* Featured/inline illustration */
.featured-image {
  margin: 1.6em 0 2em;
}

.featured-image img {
  width: 100%;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
}

.featured-image figcaption {
  margin-top: 8px;
  font-size: 0.82rem;
  color: var(--color-text-muted);
  text-align: center;
}

/* Callout / note box */
.callout {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius);
  padding: 16px 18px;
  margin: 1.6em 0;
  font-size: 0.96rem;
}

.callout strong {
  color: var(--color-primary-dark);
}

.callout.accent {
  border-left-color: var(--color-accent);
}

/* Step cards for how-to content */
.steps {
  list-style: none;
  padding: 0;
  margin: 1.4em 0;
  counter-reset: step;
}

.steps li {
  counter-increment: step;
  position: relative;
  padding: 14px 16px 14px 52px;
  margin-bottom: 10px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

.steps li::before {
  content: counter(step);
  position: absolute;
  left: 14px;
  top: 14px;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  font-size: 0.85rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Quiz / soal cards */
.quiz-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 18px 20px;
  margin-bottom: 14px;
}

.quiz-card .quiz-num {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-accent-dark);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.quiz-card p.question {
  font-weight: 600;
  margin: 6px 0 10px;
}

.quiz-card ol.options {
  list-style: upper-alpha;
  padding-left: 1.3em;
  margin: 0 0 10px;
}

.quiz-card details {
  font-size: 0.9rem;
}

.quiz-card summary {
  cursor: pointer;
  color: var(--color-primary);
  font-weight: 700;
}

.quiz-card .answer-box {
  margin-top: 8px;
  padding: 10px 12px;
  background: var(--color-tint);
  border-radius: 8px;
  color: var(--color-text-muted);
}

/* FAQ */
.faq-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  margin-bottom: 10px;
  background: var(--color-surface);
  overflow: hidden;
}

.faq-item summary {
  cursor: pointer;
  padding: 14px 18px;
  font-weight: 600;
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: 10px;
  align-items: center;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  color: var(--color-primary);
  font-size: 1.3rem;
  flex-shrink: 0;
}

.faq-item[open] summary::after {
  content: "\2212";
}

.faq-item .faq-answer {
  padding: 0 18px 16px;
  color: var(--color-text-muted);
}

/* Related links / internal linking block */
.related {
  margin: 2.4em 0;
  padding: 20px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

.related h2 {
  margin-top: 0 !important;
}

.related ul {
  padding-left: 1.2em;
}

/* Author / E-E-A-T box */
.author-box {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  margin: 2em 0;
  padding: 20px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  font-size: 0.9rem;
}

.author-box .avatar {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-family: var(--font-heading);
  flex-shrink: 0;
}

.author-box strong {
  display: block;
  font-size: 1rem;
}

.author-box .role {
  display: block;
  font-size: 0.78rem;
  color: var(--color-accent-dark);
  font-weight: 700;
  margin: 2px 0 8px;
}

.author-box p {
  color: var(--color-text-muted);
  margin: 0 0 6px;
}

.author-box p:last-child {
  margin-bottom: 0;
}

/* CTA banner */
.cta-banner {
  background: var(--color-primary-dark);
  color: #fff;
  border-radius: var(--radius);
  padding: 34px 30px;
  text-align: center;
  margin: 0 auto;
  max-width: var(--wide-width);
}

.cta-banner h2 {
  margin: 0 0 8px;
  font-size: 1.5rem;
}

.cta-banner p {
  color: #dbe6f2;
  margin: 0 0 18px;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-border);
  background: var(--color-primary-dark);
  color: #c4d3e3;
  margin-top: 40px;
}

.footer-grid {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 44px 20px 20px;
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 28px;
}

.footer-grid h4 {
  color: #fff;
  font-size: 0.88rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin: 0 0 12px;
}

.footer-grid ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-grid li {
  margin-bottom: 8px;
}

.footer-grid a {
  color: #c4d3e3;
  text-decoration: none;
  font-size: 0.9rem;
}

.footer-grid a:hover {
  color: #fff;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  font-weight: 700;
  font-family: var(--font-heading);
  margin-bottom: 10px;
  font-size: 1.05rem;
}

.footer-grid .desc {
  font-size: 0.88rem;
  color: #a9bdd3;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
}

.footer-bottom .wrap {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 16px 20px;
  font-size: 0.8rem;
  color: #9db2c9;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px;
}

@media (max-width: 780px) {
  .hero-pillar .wrap,
  .about-split {
    grid-template-columns: 1fr;
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 640px) {
  .hero-pillar h1 {
    font-size: 1.7rem;
  }
  .article-hero h1 {
    font-size: 1.5rem;
  }
  body {
    font-size: 16px;
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
}