/* ============================================================
   Matematika SMA — main.css  (gaya NEO-BRUTALISM)
   Palet dominan: hitam, putih, biru tua (navy), biru muda (sky)
   + aksen kuning / pink / hijau / merah agar tidak membosankan.
   Ciri: border tebal hitam, bayangan offset keras, tipografi
   berbobot, kartu dengan hover "angkat & miring".
   ============================================================ */

:root {
  /* inti */
  --ink: #10121a;
  --paper: #ffffff;
  --bg: #eef2f9;
  --navy: #1e3a8a;
  --blue: #2563eb;
  --blue-dark: #1d4ed8;
  --sky: #bae6fd;
  --sky-soft: #e4f2fe;
  --sky-deep: #7cc4fa;
  /* aksen */
  --yellow: #ffd43b;
  --yellow-soft: #fff3bf;
  --pink: #ff8fc7;
  --pink-soft: #ffdeef;
  --green: #37c978;
  --green-soft: #d6f7e4;
  --red: #ff5d5d;
  --red-soft: #ffe0e0;
  --orange: #ffab5e;
  --purple: #a78bfa;
  --gray: #66707f;
  --muted: #66707f;
  --border: #10121a;
  --grid-line: #dbe4f2;
  /* efek */
  --radius: 14px;
  --radius-sm: 10px;
  --bw: 3px;                    /* ketebalan border standar */
  --shadow: 5px 5px 0 var(--ink);
  --shadow-sm: 3px 3px 0 var(--ink);
  --shadow-lg: 8px 8px 0 var(--ink);
  --font: "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
  --font-display: "Arial Black", "Segoe UI", system-ui, sans-serif;
  --mono: "Cascadia Code", "Fira Code", Consolas, monospace;
  /* warna kelas */
  --k10: #2563eb;   --k10-soft: #dbeafe;
  --k11: #0ea5e9;   --k11-soft: #bae6fd;
  --k12: #ec4899;   --k12-soft: #fce7f3;
  /* alias kompatibilitas skrip lama */
  --primary: #2563eb;
  --primary-dark: #1e3a8a;
  --primary-deep: #17255c;
  --primary-soft: #dbeafe;
  --primary-border: #10121a;
  --accent: #ffd43b;
  --accent-dark: #8a6d00;
  --accent-soft: #fff3bf;
  --success: #22a558;
  --success-soft: #d6f7e4;
  --danger: #ff5d5d;
  --danger-soft: #ffe0e0;
  --surface: #ffffff;
  --text: #10121a;
  --teal: #0ea5e9;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  font-size: 16.5px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
  background-image:
    linear-gradient(var(--grid-line) 1.4px, transparent 1.4px),
    linear-gradient(90deg, var(--grid-line) 1.4px, transparent 1.4px);
  background-size: 30px 30px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

#app { display: flex; flex-direction: column; min-height: 100vh; }
main { flex: 1; }

img, canvas, svg { max-width: 100%; display: block; }

a { color: var(--blue-dark); text-decoration: none; }
a:hover { text-decoration: underline; }

h1, h2, h3, h4 { line-height: 1.2; color: var(--ink); font-weight: 900; letter-spacing: -0.3px; }

.ico { flex: none; display: inline-block; vertical-align: -4px; }

.container { width: min(1080px, 92%); margin: 0 auto; }

/* ---------- Header / Navigasi atas ---------- */
.site-header {
  background: var(--paper);
  border-bottom: var(--bw) solid var(--ink);
  position: sticky;
  top: 0;
  z-index: 50;
}
.header-inner {
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 12px 0;
  flex-wrap: wrap;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-display);
  font-size: 1.06rem;
  color: var(--ink);
  text-decoration: none !important;
  letter-spacing: 0.2px;
}
.brand:hover { text-decoration: none; }
.brand-logo {
  width: 44px; height: 44px;
  border-radius: 12px;
  background: var(--yellow);
  color: var(--ink);
  display: grid;
  place-items: center;
  font-size: 1.5rem;
  font-weight: 900;
  font-family: var(--font-display);
  border: var(--bw) solid var(--ink);
  box-shadow: var(--shadow-sm);
  transform: rotate(-4deg);
  transition: transform 0.2s;
}
.brand:hover .brand-logo { transform: rotate(4deg) scale(1.05); }
.brand small {
  display: block;
  font-family: var(--font);
  font-size: 0.64rem;
  font-weight: 800;
  color: var(--gray);
  letter-spacing: 0.8px;
  text-transform: uppercase;
}

.main-nav { display: flex; gap: 8px; flex-wrap: wrap; margin-left: auto; }
.main-nav a {
  padding: 8px 16px;
  border-radius: 10px;
  border: 2.5px solid transparent;
  font-weight: 800;
  font-size: 0.93rem;
  color: var(--ink);
  text-decoration: none !important;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  transition: transform 0.12s, box-shadow 0.12s, background 0.12s;
}
.main-nav a:hover { background: var(--sky-soft); border-color: var(--ink); text-decoration: none; }
.main-nav a.active {
  background: var(--navy);
  color: #fff;
  border-color: var(--ink);
  box-shadow: var(--shadow-sm);
  transform: translateY(-2px);
}

/* ---------- Bottom nav (mobile) ---------- */
.bottom-nav { display: none; }

@media (max-width: 820px) {
  .main-nav { display: none; }
  .bottom-nav {
    display: flex;
    position: fixed;
    bottom: 0; left: 0; right: 0;
    z-index: 80;
    background: var(--paper);
    border-top: var(--bw) solid var(--ink);
    padding: 7px 6px calc(7px + env(safe-area-inset-bottom, 0px));
    gap: 4px;
    justify-content: space-around;
  }
  .bn-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    padding: 6px 2px 5px;
    border-radius: 12px;
    border: 2.5px solid transparent;
    color: var(--ink);
    text-decoration: none !important;
    transition: transform 0.12s, background 0.12s;
    max-width: 96px;
  }
  .bn-item:active { transform: scale(0.94); }
  .bn-item .bn-ico {
    display: grid;
    place-items: center;
    width: 30px; height: 30px;
    border-radius: 9px;
  }
  .bn-item .bn-num {
    display: grid;
    place-items: center;
    width: 30px; height: 30px;
    border-radius: 9px;
    font-weight: 900;
    font-size: 0.9rem;
    font-family: var(--font-display);
    border: 2px solid var(--ink);
    background: var(--sky-soft);
  }
  .bn-item .bn-label {
    font-size: 0.6rem;
    font-weight: 800;
    letter-spacing: 0.2px;
    white-space: nowrap;
  }
  .bn-item.active {
    background: var(--navy);
    color: #fff;
    border-color: var(--ink);
    box-shadow: 2.5px 2.5px 0 var(--ink);
    transform: translateY(-3px);
  }
  .bn-item.active .bn-num { background: var(--yellow); color: var(--ink); border-color: var(--ink); }
  body { padding-bottom: calc(84px + env(safe-area-inset-bottom, 0px)); }
  .calc-fab { bottom: calc(96px + env(safe-area-inset-bottom, 0px)) !important; }
  .calc-panel { bottom: calc(162px + env(safe-area-inset-bottom, 0px)) !important; }
}

/* ---------- Hero beranda ---------- */
.hero {
  background: var(--sky);
  border-bottom: 4px solid var(--ink);
  padding: 54px 0 58px;
  position: relative;
  overflow: hidden;
}
.hero::after {
  content: "";
  position: absolute;
  right: -70px; top: -70px;
  width: 230px; height: 230px;
  border-radius: 50%;
  background: var(--yellow);
  border: var(--bw) solid var(--ink);
  opacity: 0.9;
}
.hero::before {
  content: "";
  position: absolute;
  right: 150px; bottom: -110px;
  width: 170px; height: 170px;
  border-radius: 50%;
  background: var(--pink);
  border: var(--bw) solid var(--ink);
}
.hero-inner { position: relative; z-index: 2; max-width: 740px; }
.hero .eyebrow {
  display: inline-block;
  background: var(--paper);
  border: var(--bw) solid var(--ink);
  box-shadow: var(--shadow-sm);
  padding: 6px 16px;
  border-radius: 999px;
  font-size: 0.76rem;
  font-weight: 900;
  letter-spacing: 1px;
  margin-bottom: 18px;
  transform: rotate(-1.2deg);
}
.hero h1 {
  font-family: var(--font-display);
  color: var(--ink);
  font-size: clamp(1.65rem, 4.4vw, 2.7rem);
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.2px;
}
.hero h1 .hl {
  background: var(--yellow);
  border: 2.5px solid var(--ink);
  padding: 0 10px;
  border-radius: 10px;
  display: inline-block;
  transform: rotate(-1deg);
  box-shadow: var(--shadow-sm);
}
.hero p { color: #17255c; font-size: 1.05rem; max-width: 640px; margin-bottom: 24px; font-weight: 600; }
.hero .hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }

/* ---------- Kartu Kelas (beranda) ---------- */
.section { padding: 46px 0; }
.section-head { text-align: center; margin-bottom: 32px; }
.section-head h2 {
  font-size: 1.6rem;
  display: inline-block;
  background: var(--paper);
  border: var(--bw) solid var(--ink);
  box-shadow: var(--shadow);
  border-radius: 12px;
  padding: 6px 22px;
  transform: rotate(-0.6deg);
  margin-bottom: 12px;
}
.section-head p { color: var(--gray); font-weight: 600; }

.class-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.class-card {
  background: var(--paper);
  border-radius: var(--radius);
  border: var(--bw) solid var(--ink);
  padding: 24px 22px 20px;
  text-decoration: none !important;
  display: flex;
  flex-direction: column;
  gap: 10px;
  box-shadow: var(--shadow);
  transition: transform 0.16s, box-shadow 0.16s;
  position: relative;
  overflow: hidden;
}
.class-card:hover {
  transform: translate(-3px, -3px) rotate(-0.7deg);
  box-shadow: var(--shadow-lg);
  text-decoration: none;
}
.class-card::before { content: ""; position: absolute; top: 0; left: 0; right: 0; height: 9px; border-bottom: var(--bw) solid var(--ink); }
.class-card.k10::before { background: var(--k10); }
.class-card.k11::before { background: var(--k11); }
.class-card.k12::before { background: var(--k12); }
.class-card .cc-badge {
  align-self: flex-start;
  font-family: var(--font-display);
  font-size: 0.74rem;
  padding: 4px 14px;
  border-radius: 8px;
  letter-spacing: 1px;
  border: 2.5px solid var(--ink);
  box-shadow: 2px 2px 0 var(--ink);
}
.class-card.k10 .cc-badge { background: var(--k10-soft); color: var(--navy); }
.class-card.k11 .cc-badge { background: var(--k11-soft); color: #075985; }
.class-card.k12 .cc-badge { background: var(--k12-soft); color: #9d174d; }
.class-card h3 { font-size: 1.22rem; font-family: var(--font-display); }
.class-card p { color: var(--gray); font-size: 0.93rem; flex: 1; font-weight: 600; }
.class-card .cc-topics { display: flex; flex-wrap: wrap; gap: 6px; margin: 4px 0 8px; }
.class-card .cc-topics span {
  font-size: 0.72rem;
  background: var(--bg);
  border: 2px solid var(--ink);
  padding: 2px 9px;
  border-radius: 7px;
  color: var(--ink);
  font-weight: 700;
}
.class-card .cc-cta {
  font-weight: 900;
  color: var(--blue-dark);
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.95rem;
}

/* ---------- Fitur / prinsip ---------- */
.feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.feature-card {
  background: var(--paper);
  border: var(--bw) solid var(--ink);
  border-radius: var(--radius);
  padding: 20px 16px;
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: transform 0.15s, box-shadow 0.15s;
}
.feature-card:hover { transform: translate(-2px, -2px) rotate(0.6deg); box-shadow: var(--shadow); }
.feature-card .fi {
  width: 52px; height: 52px;
  margin: 0 auto 12px;
  border-radius: 13px;
  border: var(--bw) solid var(--ink);
  box-shadow: 2.5px 2.5px 0 var(--ink);
  display: grid;
  place-items: center;
  color: var(--ink);
  transform: rotate(-3deg);
  transition: transform 0.2s;
}
.feature-card:hover .fi { transform: rotate(3deg) scale(1.06); }
.feature-card:nth-child(4n+1) .fi { background: var(--sky); }
.feature-card:nth-child(4n+2) .fi { background: var(--yellow); }
.feature-card:nth-child(4n+3) .fi { background: var(--pink-soft); }
.feature-card:nth-child(4n+4) .fi { background: var(--green-soft); }
.feature-card h4 { font-size: 0.99rem; margin-bottom: 4px; }
.feature-card p { font-size: 0.84rem; color: var(--gray); font-weight: 600; }

/* ---------- Dashboard Kelas ---------- */
.page-head { padding: 36px 0 8px; }
.page-head h1 {
  font-size: 1.8rem;
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  font-family: var(--font-display);
  text-transform: uppercase;
}
.page-head .sub { color: var(--gray); margin-top: 8px; font-weight: 600; }
.page-head .kelas-chip {
  font-family: var(--font-display);
  font-size: 0.82rem;
  padding: 6px 16px;
  border-radius: 10px;
  border: var(--bw) solid var(--ink);
  box-shadow: var(--shadow-sm);
  vertical-align: middle;
  transform: rotate(-2deg);
  display: inline-block;
}
.kelas-chip.k10, .dash.k10 .kelas-chip { background: var(--k10-soft); color: var(--navy); }
.kelas-chip.k11, .dash.k11 .kelas-chip { background: var(--k11-soft); color: #075985; }
.kelas-chip.k12, .dash.k12 .kelas-chip { background: var(--k12-soft); color: #9d174d; }

.overview-row {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 20px;
  margin: 22px 0 32px;
}
.stat-card {
  background: var(--paper);
  border: var(--bw) solid var(--ink);
  border-radius: var(--radius);
  padding: 18px 22px;
  box-shadow: var(--shadow);
}
.stat-card .sc-label { font-size: 0.78rem; font-weight: 900; color: var(--ink); text-transform: uppercase; letter-spacing: 0.6px; }
.stat-card .sc-value { font-size: 1.7rem; font-weight: 900; font-family: var(--font-display); color: var(--navy); margin-top: 2px; }
.stat-card .sc-hint { font-size: 0.8rem; color: var(--gray); font-weight: 600; }

/* ---------- Progress bar ---------- */
.progress {
  background: var(--paper);
  border: 2.5px solid var(--ink);
  border-radius: 999px;
  height: 15px;
  overflow: hidden;
}
.progress > span {
  display: block;
  height: 100%;
  border-radius: 999px;
  background: repeating-linear-gradient(45deg, var(--blue) 0 10px, var(--blue-dark) 10px 20px);
  transition: width 0.5s cubic-bezier(0.22, 1, 0.36, 1);
  background-size: 28px 28px;
  animation: barStripe 1.2s linear infinite;
}
@keyframes barStripe { from { background-position: 0 0; } to { background-position: 28px 0; } }
.progress.thin { height: 10px; }
.progress.done > span {
  background: repeating-linear-gradient(45deg, var(--green) 0 10px, #2aa963 10px 20px);
  background-size: 28px 28px;
}

/* ---------- Grid kartu topik ---------- */
.topic-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; margin-bottom: 48px; }
.topic-card {
  background: var(--paper);
  border: var(--bw) solid var(--ink);
  border-radius: var(--radius);
  padding: 20px;
  display: flex;
  gap: 16px;
  align-items: flex-start;
  text-decoration: none !important;
  box-shadow: var(--shadow);
  transition: transform 0.16s, box-shadow 0.16s;
  position: relative;
}
.topic-card:hover { transform: translate(-3px, -3px) rotate(-0.5deg); box-shadow: var(--shadow-lg); }
.topic-card .tc-icon {
  width: 58px; height: 58px;
  min-width: 58px;
  border-radius: 14px;
  border: var(--bw) solid var(--ink);
  box-shadow: var(--shadow-sm);
  display: grid;
  place-items: center;
  font-size: 1.55rem;
  font-weight: 900;
  transform: rotate(-3deg);
  transition: transform 0.2s;
}
.topic-card:hover .tc-icon { transform: rotate(4deg) scale(1.07); }
.dash.k10 .tc-icon { background: var(--k10-soft); }
.dash.k11 .tc-icon { background: var(--k11-soft); }
.dash.k12 .tc-icon { background: var(--k12-soft); }
.topic-card .tc-body { flex: 1; }
.topic-card h3 { font-size: 1.07rem; margin-bottom: 2px; }
.topic-card .tc-sub { color: var(--gray); font-size: 0.88rem; margin-bottom: 10px; font-weight: 600; }
.topic-card .tc-meta { display: flex; align-items: center; gap: 10px; font-size: 0.82rem; color: var(--gray); font-weight: 700; flex-wrap: wrap; }
.topic-card .tc-score {
  font-weight: 900;
  font-size: 0.76rem;
  padding: 3px 11px;
  border-radius: 8px;
  border: 2.5px solid var(--ink);
  box-shadow: 2px 2px 0 var(--ink);
}
.tc-score.good { background: var(--green-soft); color: #0b7a44; }
.tc-score.mid { background: var(--yellow-soft); color: #8a6d00; }
.tc-score.none { background: var(--bg); color: var(--gray); }
.topic-card.completed::after {
  content: "✓ SELESAI";
  position: absolute;
  top: -12px; right: 14px;
  font-family: var(--font-display);
  font-size: 0.64rem;
  font-weight: 900;
  color: var(--ink);
  background: var(--green);
  padding: 3px 12px;
  border-radius: 8px;
  border: 2.5px solid var(--ink);
  box-shadow: 2px 2px 0 var(--ink);
  transform: rotate(2deg);
}

/* ---------- Halaman Topik ---------- */
.topic-hero {
  background: var(--paper);
  border: var(--bw) solid var(--ink);
  border-radius: var(--radius);
  padding: 26px 28px;
  margin: 26px 0 20px;
  box-shadow: var(--shadow);
}
.topic-hero .th-top { display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }
.topic-hero .th-icon {
  width: 66px; height: 66px;
  border-radius: 16px;
  border: var(--bw) solid var(--ink);
  box-shadow: var(--shadow-sm);
  display: grid;
  place-items: center;
  font-size: 1.8rem;
  font-weight: 900;
  background: var(--sky);
  transform: rotate(-3deg);
}
.topic-hero h1 { font-size: 1.5rem; font-family: var(--font-display); }
.topic-hero .th-sub { color: var(--gray); font-size: 0.95rem; font-weight: 600; }

.tujuan-box {
  margin-top: 18px;
  background: var(--yellow-soft);
  border: var(--bw) solid var(--ink);
  border-left: 8px solid var(--yellow);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  font-size: 0.96rem;
  font-weight: 600;
  box-shadow: var(--shadow-sm);
}
.tujuan-box strong { color: #8a6d00; }

/* ---------- Stepper 5 tahap ---------- */
.stepper {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
  margin: 24px 0;
}
.step {
  background: var(--paper);
  border: var(--bw) solid var(--ink);
  border-radius: var(--radius-sm);
  padding: 10px 6px 8px;
  text-align: center;
  cursor: default;
  transition: transform 0.14s, box-shadow 0.14s, background 0.14s;
  font: inherit;
  color: var(--gray);
}
.step .st-num {
  display: inline-grid;
  place-items: center;
  width: 30px; height: 30px;
  border-radius: 9px;
  background: var(--bg);
  border: 2.5px solid var(--ink);
  color: var(--ink);
  font-weight: 900;
  font-size: 0.88rem;
  margin-bottom: 5px;
  font-family: var(--font-display);
}
.step .st-label { font-size: 0.72rem; font-weight: 900; letter-spacing: 0.3px; display: block; }
.step.active {
  background: var(--yellow);
  color: var(--ink);
  box-shadow: var(--shadow);
  transform: translateY(-4px);
}
.step.active .st-num { background: var(--navy); color: #fff; }
.step.done { background: var(--green-soft); }
.step.done .st-num { background: var(--green); color: var(--ink); }
.step.done .st-label { color: #0b7a44; }
.step.clickable { cursor: pointer; }
.step.clickable:hover { transform: translateY(-3px); box-shadow: var(--shadow-sm); }

.stage-card {
  background: var(--paper);
  border: var(--bw) solid var(--ink);
  border-radius: var(--radius);
  padding: 30px;
  box-shadow: var(--shadow);
  animation: fadeUp 0.28s ease;
}
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: none; }
}
.stage-card h2 {
  font-size: 1.32rem;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}
.stage-card h2 .stage-tag {
  font-family: var(--font-display);
  font-size: 0.68rem;
  background: var(--sky);
  color: var(--ink);
  border: 2.5px solid var(--ink);
  border-radius: 8px;
  padding: 4px 12px;
  letter-spacing: 1px;
  box-shadow: 2px 2px 0 var(--ink);
}
.stage-card p.lead { font-size: 1.03rem; margin-bottom: 12px; }
.stage-card .stage-body p { margin-bottom: 10px; }
.stage-card .stage-body ul { margin: 8px 0 14px 22px; }
.stage-card .stage-body li { margin-bottom: 6px; }

.stage-nav {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin: 24px 0 46px;
  flex-wrap: wrap;
}
.stage-nav .spacer { flex: 1; }

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  font-size: 0.85rem;
  color: var(--gray);
  margin-top: 22px;
  font-weight: 700;
}
.breadcrumb a {
  color: var(--ink);
  background: var(--sky-soft);
  border: 2px solid var(--ink);
  border-radius: 7px;
  padding: 1px 10px;
}
.breadcrumb a:hover { background: var(--sky); }
.breadcrumb .sep { color: var(--gray); }

/* Formula box */
.formula {
  background: var(--navy);
  color: #dbeafe;
  font-family: var(--mono);
  font-size: 1.06rem;
  text-align: center;
  border: var(--bw) solid var(--ink);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
  padding: 15px 18px;
  margin: 16px 0;
  overflow-x: auto;
}
.formula b, .formula strong { color: var(--yellow); }

.concept-section {
  border: 2.5px solid var(--ink);
  border-radius: var(--radius-sm);
  padding: 18px 20px;
  margin-bottom: 18px;
  background: #fff;
  transition: background 0.3s, box-shadow 0.3s;
  position: relative;
}
.concept-section h3 {
  font-size: 1.06rem;
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 9px;
}
.concept-section h3 .cs-ico {
  width: 30px; height: 30px;
  min-width: 30px;
  border-radius: 9px;
  border: 2.5px solid var(--ink);
  background: var(--sky);
  display: inline-grid;
  place-items: center;
  font-size: 0.9rem;
  font-family: var(--font-display);
  box-shadow: 2px 2px 0 var(--ink);
}
.concept-section p { margin-bottom: 8px; font-size: 0.97rem; }
.concept-section table { margin: 10px 0; }
/* bagian yang sedang dibacakan TTS */
.concept-section.tts-active, .tts-active {
  background: var(--yellow-soft);
  box-shadow: var(--shadow-sm);
  outline: 3px dashed var(--blue);
  outline-offset: 3px;
}

/* ---------- TTS bar ---------- */
.tts-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--sky-soft);
  border: var(--bw) solid var(--ink);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
  padding: 10px 14px;
  margin: 0 0 18px;
  flex-wrap: wrap;
}
.tts-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font: inherit;
  font-weight: 900;
  font-size: 0.9rem;
  background: var(--paper);
  color: var(--ink);
  border: 2.5px solid var(--ink);
  border-radius: 10px;
  box-shadow: 2.5px 2.5px 0 var(--ink);
  padding: 8px 16px;
  cursor: pointer;
  transition: transform 0.12s, box-shadow 0.12s, background 0.12s;
}
.tts-btn:hover { transform: translate(-1px, -1px); box-shadow: 4px 4px 0 var(--ink); }
.tts-btn:active { transform: translate(2px, 2px); box-shadow: 1px 1px 0 var(--ink); }
.tts-btn.tts-play.playing { background: var(--yellow); }
.tts-btn.tts-stop { padding: 8px 12px; background: var(--red-soft); }
.tts-info { display: flex; flex-direction: column; font-size: 0.88rem; }
.tts-info b { font-size: 0.95rem; }
.tts-info .tts-status { color: var(--gray); font-weight: 700; font-size: 0.78rem; }

/* ---------- Footer ---------- */
.site-footer {
  background: var(--navy);
  color: #dbeafe;
  border-top: 4px solid var(--ink);
  padding: 26px 0;
  margin-top: auto;
  font-size: 0.88rem;
  font-weight: 600;
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}
.footer-inner strong { color: #fff; }
.footer-inner a {
  color: var(--yellow);
  font-weight: 800;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.footer-inner a:hover { text-decoration: underline; }

/* ---------- Responsif ---------- */
@media (max-width: 900px) {
  .class-grid, .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .overview-row { grid-template-columns: 1fr 1fr; }
  .overview-row .stat-card:first-child { grid-column: 1 / -1; }
}
@media (max-width: 640px) {
  body { font-size: 15.5px; }
  .class-grid { grid-template-columns: 1fr; }
  .feature-grid { grid-template-columns: 1fr 1fr; }
  .topic-grid { grid-template-columns: 1fr; }
  .stepper { grid-template-columns: repeat(5, 1fr); gap: 4px; }
  .step { padding: 8px 2px 6px; border-width: 2.5px; }
  .step .st-label { font-size: 0.55rem; line-height: 1.25; overflow-wrap: anywhere; }
  .step .st-num { width: 22px; height: 22px; font-size: 0.72rem; margin-bottom: 3px; }
  .stage-card { padding: 20px 16px; }
  .topic-hero { padding: 20px 18px; }
  .hero { padding: 38px 0 44px; }
  .hero::after { width: 150px; height: 150px; right: -50px; top: -50px; }
  .hero::before { width: 110px; height: 110px; right: 90px; }
  .header-inner { gap: 8px; padding: 10px 0; }
  .section-head h2 { font-size: 1.25rem; }
}