:root {
  --ink: #17211d;
  --muted: #5d6a65;
  --line: #d8ded9;
  --paper: #f8faf6;
  --white: #ffffff;
  --green: #1f7a52;
  --green-dark: #12513a;
  --lime: #c7ef6f;
  --amber: #f1b64b;
  --blue: #246b8f;
  --shadow: 0 24px 70px rgba(23, 33, 29, 0.13);
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
}

@keyframes fade-rise {
  from {
    opacity: 0;
    transform: translateY(18px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes soft-pulse {
  0% {
    box-shadow: 0 18px 50px rgba(23, 33, 29, 0.08);
  }

  45% {
    box-shadow: 0 24px 70px rgba(31, 122, 82, 0.18);
  }

  100% {
    box-shadow: 0 18px 50px rgba(23, 33, 29, 0.08);
  }
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

a {
  color: inherit;
  text-decoration: none;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 18px clamp(20px, 5vw, 64px);
  border-bottom: 1px solid rgba(216, 222, 217, 0.8);
  background: rgba(248, 250, 246, 0.92);
  backdrop-filter: blur(16px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  letter-spacing: 0;
}

.brand,
.site-nav a,
.button,
.topic-card,
.article-list a,
.featured-article,
.article-card,
.principle-card,
.faq-list details,
.calculator-form,
.calculator-result,
.battery-quiz-card {
  transition:
    transform 180ms var(--ease),
    box-shadow 180ms var(--ease),
    border-color 180ms var(--ease),
    background-color 180ms var(--ease),
    color 180ms var(--ease);
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 8px;
  background: var(--green);
  color: var(--white);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 22px;
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 600;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  color: var(--green-dark);
}

.nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.nav-toggle span:not(.sr-only) {
  display: block;
  width: 18px;
  height: 2px;
  margin: 4px auto;
  background: var(--ink);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.12fr) minmax(320px, 0.88fr);
  gap: clamp(32px, 6vw, 88px);
  align-items: center;
  min-height: calc(100vh - 76px);
  padding: clamp(56px, 8vw, 110px) clamp(20px, 5vw, 64px) clamp(44px, 7vw, 86px);
  background:
    linear-gradient(120deg, rgba(31, 122, 82, 0.12), rgba(36, 107, 143, 0.08) 48%, rgba(241, 182, 75, 0.14)),
    var(--paper);
}

.hero-content {
  max-width: 760px;
  animation: fade-rise 650ms var(--ease) both;
}

.battery-quiz-card {
  animation: fade-rise 760ms var(--ease) 120ms both;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--green-dark);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 780px;
  margin-bottom: 24px;
  font-size: clamp(2.35rem, 5.35vw, 4.65rem);
  line-height: 1;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(2rem, 4vw, 3.6rem);
  line-height: 1.05;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 10px;
  font-size: 1.18rem;
}

.hero-copy {
  max-width: 640px;
  color: var(--muted);
  font-size: clamp(1.06rem, 1.5vw, 1.28rem);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 34px;
}

.hero-visual {
  display: block;
  width: min(100%, 560px);
  aspect-ratio: 38 / 11;
  margin-top: clamp(28px, 5vw, 48px);
  border-radius: 8px;
  box-shadow: 0 18px 46px rgba(23, 33, 29, 0.07);
  object-fit: cover;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 20px;
  border-radius: 8px;
  font-weight: 800;
}

.button.primary {
  background: var(--green);
  color: var(--white);
}

.button:hover,
.button:focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 12px 28px rgba(23, 33, 29, 0.13);
}

.button.secondary {
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.72);
  color: var(--green-dark);
}

.battery-quiz-card {
  width: min(100%, 420px);
  justify-self: end;
  padding: 24px;
  border: 1px solid rgba(18, 81, 58, 0.12);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.9);
  box-shadow: var(--shadow);
}

.quiz-heading,
.site-footer,
.intro-band div,
.about-band {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
}

.quiz-heading {
  align-items: flex-start;
  margin-bottom: 18px;
}

.quiz-heading span {
  color: var(--muted);
  font-size: 0.92rem;
  font-weight: 800;
}

.battery-quiz-card > p {
  margin-bottom: 18px;
  color: var(--muted);
}

.quiz-toggle {
  width: 100%;
}

.battery-quiz {
  margin-top: 18px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.battery-quiz[hidden] {
  display: none;
}

.quiz-result {
  padding: 18px;
  border-radius: 8px;
  background: rgba(199, 239, 111, 0.28);
}

.quiz-loading {
  display: grid;
  min-height: 230px;
  align-content: center;
  justify-items: start;
  padding: 18px;
  border-radius: 8px;
  background: rgba(199, 239, 111, 0.18);
}

.quiz-loading .loading-spinner {
  margin-bottom: 18px;
}

.wizard-progress {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 6px;
  margin-bottom: 12px;
}

.wizard-progress span {
  height: 5px;
  border-radius: 99px;
  background: rgba(31, 122, 82, 0.16);
}

.wizard-progress span.is-active {
  background: var(--green);
}

.wizard-count,
.wizard-hint {
  color: var(--muted);
  font-size: 0.84rem;
  font-weight: 700;
}

.wizard-step h3 {
  margin-bottom: 14px;
  font-size: 1.25rem;
  line-height: 1.2;
}

.wizard-step.is-active {
  animation: fade-rise 260ms var(--ease) both;
}

.choice-grid {
  display: grid;
  gap: 9px;
}

.choice-grid label {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  padding: 11px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
  color: var(--ink);
  font-weight: 800;
  cursor: pointer;
}

.choice-grid label:hover {
  transform: translateY(-1px);
  border-color: rgba(31, 122, 82, 0.42);
}

.choice-grid label:has(input:checked) {
  border-color: var(--green);
  background: rgba(199, 239, 111, 0.28);
}

.choice-grid input {
  accent-color: var(--green);
}

.wizard-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 16px;
}

.wizard-actions .button {
  width: 100%;
  border: 0;
  cursor: pointer;
}

.wizard-actions .button:disabled {
  cursor: not-allowed;
  opacity: 0.48;
}

.wizard-actions .button.is-loading {
  cursor: wait;
}

.quiz-result span,
.article-list span {
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 700;
}

.quiz-result strong {
  display: block;
  margin: 4px 0 8px;
  font-size: 1.34rem;
  line-height: 1.15;
}

.quiz-result p {
  margin-bottom: 8px;
  color: var(--muted);
}

.quiz-result small {
  color: var(--green-dark);
  font-weight: 800;
}

.quiz-explainer {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid rgba(18, 81, 58, 0.16);
}

.quiz-explainer strong {
  margin-bottom: 8px;
  font-size: 1rem;
}

.quiz-explainer ul {
  display: grid;
  gap: 7px;
  padding-left: 1.1rem;
  margin: 0 0 14px;
}

.quiz-explainer li {
  color: var(--muted);
  font-size: 0.9rem;
}

.quiz-explainer a {
  color: var(--green-dark);
  font-weight: 800;
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 5px;
}

.quiz-source {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1.45;
}

.quiz-source a {
  color: var(--green-dark);
  font-weight: 800;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.trust-box {
  margin: 18px 0;
  padding: 16px;
  border: 1px solid rgba(18, 81, 58, 0.15);
  border-radius: 8px;
  background: rgba(248, 250, 246, 0.92);
}

.trust-box.compact {
  margin: 14px 0 0;
}

.trust-box strong {
  display: block;
  margin-bottom: 6px;
  color: var(--ink);
  font-size: 0.95rem;
}

.trust-box p {
  margin-bottom: 8px;
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.5;
}

.trust-box a {
  color: var(--green-dark);
  font-size: 0.86rem;
  font-weight: 800;
  text-decoration: underline;
  text-underline-offset: 4px;
}

.trust-section {
  background:
    linear-gradient(120deg, rgba(199, 239, 111, 0.18), rgba(36, 107, 143, 0.06)),
    var(--paper);
}

.principles-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 34px;
}

.principle-card {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.principle-card span {
  display: inline-grid;
  width: 38px;
  height: 38px;
  place-items: center;
  margin-bottom: 22px;
  border-radius: 8px;
  background: rgba(199, 239, 111, 0.38);
  color: var(--green-dark);
  font-weight: 800;
}

.principle-card p {
  color: var(--muted);
}

.calculator-section {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(320px, 0.8fr);
  gap: clamp(28px, 5vw, 64px);
  align-items: start;
  padding: clamp(54px, 8vw, 94px) clamp(20px, 5vw, 64px);
}

.calculator-form,
.calculator-result {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
  box-shadow: 0 18px 50px rgba(23, 33, 29, 0.08);
}

.calculator-form {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  padding: 22px;
}

.calc-field,
.calc-check {
  display: grid;
  gap: 7px;
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 800;
}

.calc-field input,
.calc-field select {
  width: 100%;
  min-height: 46px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
  color: var(--ink);
  font: inherit;
  font-weight: 700;
}

.input-suffix {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.input-suffix span {
  padding: 0 12px;
  color: var(--muted);
  font-weight: 800;
}

.calculator-form .input-suffix input {
  border: 0;
}

.calc-check {
  grid-column: 1 / -1;
  grid-template-columns: 20px 1fr;
}

.calc-check input {
  width: 18px;
  height: 18px;
  margin-top: 3px;
  accent-color: var(--green);
}

.calc-actions {
  display: grid;
  grid-column: 1 / -1;
  gap: 10px;
  padding-top: 6px;
}

.calc-actions .button {
  width: fit-content;
  border: 0;
  cursor: pointer;
}

.calc-actions .button:disabled {
  cursor: wait;
  opacity: 0.72;
}

.calc-actions p {
  margin: 0;
  color: var(--muted);
  font-size: 0.86rem;
}

.calculator-result {
  position: sticky;
  top: 104px;
  padding: 24px;
}

.calculator-result.is-empty {
  background:
    linear-gradient(120deg, rgba(199, 239, 111, 0.2), rgba(36, 107, 143, 0.06)),
    var(--white);
}

.calculator-result.is-stale {
  border-color: rgba(241, 182, 75, 0.64);
}

.calculator-result.is-updating {
  animation: soft-pulse 520ms var(--ease);
}

.calc-output[hidden],
.calc-placeholder[hidden],
.calc-loading[hidden] {
  display: none;
}

.calc-placeholder span,
.calc-loading span:not(.loading-spinner),
.calc-output > span,
.calc-metrics span {
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 800;
}

.calc-placeholder strong,
.calc-loading strong,
.calc-output > strong {
  display: block;
  margin: 4px 0 8px;
  font-size: clamp(2rem, 4vw, 3.3rem);
  line-height: 1;
}

.calc-placeholder p,
.calc-loading p,
.calc-output > p {
  color: var(--muted);
}

.calc-loading {
  display: grid;
  min-height: 250px;
  align-content: center;
  justify-items: start;
}

.loading-spinner {
  width: 42px;
  height: 42px;
  margin-bottom: 18px;
  border: 4px solid rgba(31, 122, 82, 0.16);
  border-top-color: var(--green);
  border-radius: 999px;
  animation: spin 760ms linear infinite;
}

.calc-metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin: 20px 0;
}

.calc-metrics div {
  padding: 14px;
  border-radius: 8px;
  background: rgba(199, 239, 111, 0.22);
}

.calc-metrics strong {
  display: block;
  margin-top: 4px;
  font-size: 1rem;
  line-height: 1.15;
}

.intro-band {
  padding: 0 clamp(20px, 5vw, 64px);
}

.intro-band div {
  max-width: 1180px;
  margin: 0 auto;
  padding: 22px 0;
  border-block: 1px solid var(--line);
}

.intro-band span {
  max-width: 760px;
  color: var(--muted);
}

.section,
.split-section,
.about-band {
  padding: clamp(64px, 9vw, 118px) clamp(20px, 5vw, 64px);
}

.section-heading {
  max-width: 760px;
  margin-bottom: 34px;
}

.section-heading-with-visual {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(220px, 330px);
  gap: clamp(24px, 5vw, 52px);
  align-items: end;
  max-width: 1040px;
}

.section-visual,
.split-visual {
  display: block;
  width: 100%;
  border-radius: 8px;
  box-shadow: 0 18px 46px rgba(23, 33, 29, 0.07);
  object-fit: cover;
}

.section-visual {
  aspect-ratio: 7 / 4;
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.topic-card {
  display: flex;
  flex-direction: column;
  min-height: 240px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.topic-card:hover,
.article-card:hover,
.principle-card:hover,
.roadmap-card:hover,
.faq-list details:hover {
  transform: translateY(-3px);
  box-shadow: 0 18px 42px rgba(23, 33, 29, 0.09);
}

.topic-icon {
  display: inline-grid;
  place-items: center;
  width: 42px;
  height: 42px;
  margin-bottom: 34px;
  border-radius: 8px;
  background: rgba(199, 239, 111, 0.38);
  color: var(--green-dark);
  font-weight: 800;
}

.topic-card p,
.split-section p,
.about-band p {
  color: var(--muted);
}

.text-link,
.start-advice a {
  display: inline-flex;
  width: fit-content;
  margin-top: auto;
  color: var(--green-dark);
  font-weight: 800;
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 5px;
}

.start-advice a {
  color: var(--lime);
}

.split-section {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(320px, 1.1fr);
  gap: clamp(36px, 6vw, 88px);
  align-items: start;
  background: var(--ink);
  color: var(--white);
}

.split-section .eyebrow {
  color: var(--lime);
}

.split-section p {
  max-width: 620px;
  color: rgba(255, 255, 255, 0.72);
}

.split-visual {
  width: min(100%, 420px);
  aspect-ratio: 26 / 15;
  margin-top: 28px;
  box-shadow: 0 24px 62px rgba(0, 0, 0, 0.18);
}

.start-flow {
  display: grid;
  gap: 16px;
}

.start-options {
  display: grid;
  gap: 10px;
}

.start-option {
  min-height: 48px;
  padding: 0 16px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.06);
  color: rgba(255, 255, 255, 0.78);
  font: inherit;
  font-weight: 800;
  text-align: left;
  cursor: pointer;
  transition:
    transform 180ms var(--ease),
    border-color 180ms var(--ease),
    background-color 180ms var(--ease),
    color 180ms var(--ease);
}

.start-option:hover,
.start-option:focus-visible {
  transform: translateX(3px);
  border-color: rgba(199, 239, 111, 0.5);
  color: var(--white);
}

.start-option.is-active {
  border-color: rgba(199, 239, 111, 0.68);
  background: rgba(199, 239, 111, 0.14);
  color: var(--white);
}

.start-advice {
  padding: 24px;
  border: 1px solid rgba(199, 239, 111, 0.28);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.08);
  box-shadow: 0 24px 62px rgba(0, 0, 0, 0.16);
}

.start-advice > span {
  color: var(--lime);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.start-advice h3 {
  margin: 10px 0 12px;
  font-size: clamp(1.45rem, 2.8vw, 2.15rem);
  line-height: 1.08;
}

.start-advice-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 22px 0;
}

.start-advice-grid div {
  padding: 16px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.06);
}

.start-advice-grid strong {
  display: block;
  margin-bottom: 6px;
  color: var(--white);
}

.start-advice-grid p,
.start-advice > p {
  margin-bottom: 0;
}

.articles-section {
  background: var(--white);
}

.featured-articles {
  display: grid;
  grid-template-columns: minmax(280px, 0.82fr) minmax(0, 1fr);
  gap: 16px;
  align-items: stretch;
  max-width: 1120px;
}

.featured-article {
  display: flex;
  min-height: 100%;
  flex-direction: column;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
}

.featured-article img {
  width: 100%;
  aspect-ratio: 16 / 9;
  margin-bottom: 18px;
  border: 1px solid rgba(31, 122, 82, 0.16);
  border-radius: 8px;
  background: var(--white);
  object-fit: cover;
}

.article-list {
  display: grid;
  gap: 12px;
}

.featured-article span,
.article-list span {
  color: var(--green-dark);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.featured-article strong {
  font-size: clamp(1.55rem, 2.5vw, 2.2rem);
  line-height: 1.08;
}

.featured-article p {
  margin: 14px 0 0;
  color: var(--muted);
}

.featured-article:hover,
.featured-article:focus-visible {
  transform: translateY(-3px);
  box-shadow: 0 18px 42px rgba(23, 33, 29, 0.09);
}

.article-list a {
  display: grid;
  grid-template-columns: 112px minmax(82px, 110px) 1fr;
  gap: 16px;
  align-items: center;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.article-list img {
  width: 100%;
  aspect-ratio: 16 / 9;
  border: 1px solid rgba(31, 122, 82, 0.13);
  border-radius: 8px;
  background: var(--paper);
  object-fit: cover;
}

.article-list strong {
  font-size: clamp(1.05rem, 1.5vw, 1.35rem);
  line-height: 1.2;
}

.article-list a:hover strong,
.article-list a:focus-visible strong {
  color: var(--green);
}

.article-list a:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 34px rgba(23, 33, 29, 0.08);
}

.roadmap-section {
  background: var(--ink);
  color: var(--white);
}

.roadmap-section .eyebrow {
  color: var(--lime);
}

.roadmap-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.roadmap-card {
  min-height: 250px;
  padding: 22px;
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.06);
  transition:
    transform 180ms var(--ease),
    box-shadow 180ms var(--ease),
    border-color 180ms var(--ease),
    background-color 180ms var(--ease);
}

.roadmap-card span {
  display: inline-block;
  margin-bottom: 38px;
  color: var(--lime);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.roadmap-card p {
  color: rgba(255, 255, 255, 0.72);
}

.roadmap-section .button.secondary {
  border-color: rgba(255, 255, 255, 0.28);
  background: rgba(255, 255, 255, 0.08);
  color: var(--white);
}

.faq-section {
  background: var(--paper);
}

.faq-list {
  display: grid;
  gap: 12px;
  max-width: 900px;
}

.faq-list details {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.faq-list summary {
  cursor: pointer;
  padding: 20px 22px;
  color: var(--ink);
  font-size: clamp(1.05rem, 1.6vw, 1.25rem);
  font-weight: 800;
}

.faq-list p {
  margin: 0;
  padding: 0 22px 22px;
  color: var(--muted);
}

.section-button {
  margin-top: 28px;
}

.articles-index {
  padding: clamp(54px, 8vw, 94px) clamp(20px, 5vw, 64px);
}

.articles-index-inner {
  width: min(1120px, 100%);
  margin: 0 auto;
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 34px;
}

.article-card {
  display: flex;
  min-height: 250px;
  flex-direction: column;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.article-card-image {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  margin-bottom: 18px;
  border: 1px solid rgba(31, 122, 82, 0.16);
  border-radius: 8px;
  background: var(--paper);
  object-fit: cover;
}

.article-card span {
  margin-bottom: 22px;
  color: var(--green-dark);
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.article-card h2 {
  margin-bottom: 14px;
  font-size: 1.45rem;
  line-height: 1.18;
}

.article-card p {
  color: var(--muted);
}

.article-card strong {
  margin-top: auto;
  color: var(--green-dark);
}

.about-band {
  align-items: flex-start;
  background: linear-gradient(90deg, rgba(199, 239, 111, 0.32), rgba(241, 182, 75, 0.2));
}

.about-band > div,
.about-band > p {
  flex: 1;
}

.site-footer {
  padding: 30px clamp(20px, 5vw, 64px);
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-weight: 700;
}

.site-footer strong {
  display: block;
  color: var(--ink);
  font-size: 1rem;
}

.site-footer p {
  margin: 6px 0 0;
  color: var(--muted);
}

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

.site-footer a {
  color: var(--green-dark);
}

.article-hero {
  padding: clamp(54px, 8vw, 94px) clamp(20px, 5vw, 64px) clamp(32px, 5vw, 58px);
  background:
    linear-gradient(120deg, rgba(31, 122, 82, 0.11), rgba(241, 182, 75, 0.16)),
    var(--paper);
}

.article-hero-inner {
  animation: fade-rise 580ms var(--ease) both;
}

.article-hero-inner,
.article-layout,
.article-next {
  width: min(1120px, 100%);
  margin: 0 auto;
}

.breadcrumb {
  display: inline-flex;
  margin-bottom: 28px;
  color: var(--green-dark);
  font-weight: 800;
}

.article-hero h1 {
  max-width: 920px;
  font-size: clamp(2.45rem, 5vw, 4.8rem);
}

.article-intro {
  max-width: 760px;
  color: var(--muted);
  font-size: clamp(1.08rem, 1.5vw, 1.24rem);
}

.article-cover {
  display: block;
  width: min(900px, 100%);
  aspect-ratio: 16 / 9;
  margin-top: 30px;
  border: 1px solid rgba(31, 122, 82, 0.16);
  border-radius: 8px;
  background: var(--white);
  box-shadow: 0 18px 50px rgba(23, 33, 29, 0.08);
  object-fit: cover;
}

.article-layout {
  display: grid;
  grid-template-columns: minmax(180px, 260px) minmax(0, 760px);
  gap: clamp(34px, 6vw, 84px);
  padding: clamp(52px, 8vw, 92px) clamp(20px, 5vw, 64px);
}

.article-toc {
  position: sticky;
  top: 104px;
  align-self: start;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.article-toc strong {
  display: block;
  margin-bottom: 12px;
}

.article-toc a {
  display: block;
  padding: 8px 0;
  color: var(--muted);
  font-weight: 700;
}

.article-content {
  font-size: 1.04rem;
}

.article-content h2 {
  margin-top: 46px;
  font-size: clamp(1.7rem, 3vw, 2.5rem);
}

.article-content h2:first-child {
  margin-top: 0;
}

.article-content p,
.article-content li {
  color: var(--muted);
}

.article-content ul {
  padding-left: 1.2rem;
}

.note-box {
  margin: 32px 0;
  padding: 22px;
  border-left: 5px solid var(--green);
  border-radius: 8px;
  background: var(--white);
}

.note-box strong {
  display: block;
  margin-bottom: 6px;
}

.article-next {
  padding: 0 clamp(20px, 5vw, 64px) clamp(68px, 8vw, 104px);
}

.article-next a {
  display: block;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.article-next a:hover {
  transform: translateY(-2px);
  box-shadow: 0 16px 40px rgba(23, 33, 29, 0.09);
}

.article-next span {
  display: block;
  margin-bottom: 8px;
  color: var(--muted);
  font-weight: 800;
}

.glossary-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 34px;
}

.glossary-nav a {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  padding: 0 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
  color: var(--green-dark);
  font-weight: 800;
}

.glossary-list {
  display: grid;
  gap: 22px;
}

.glossary-group {
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.glossary-group h2 {
  margin-bottom: 20px;
  font-size: clamp(1.65rem, 3vw, 2.4rem);
}

.glossary-group article {
  display: grid;
  grid-template-columns: minmax(150px, 220px) minmax(0, 1fr);
  gap: 16px;
  padding: 18px 0;
  border-top: 1px solid var(--line);
}

.glossary-group h3 {
  margin-bottom: 0;
  color: var(--green-dark);
}

.glossary-group p {
  margin-bottom: 6px;
  color: var(--ink);
}

.glossary-group small {
  grid-column: 2;
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.45;
}

.glossary-group a {
  color: var(--green-dark);
  font-weight: 800;
  text-decoration: underline;
  text-underline-offset: 4px;
}

@media (max-width: 960px) {
  .hero,
  .split-section,
  .about-band {
    grid-template-columns: 1fr;
  }

  .battery-quiz-card {
    justify-self: start;
  }

  .hero-visual {
    width: min(100%, 520px);
  }

  .topic-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .roadmap-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .about-band {
    display: block;
  }

  .featured-articles {
    grid-template-columns: 1fr;
  }

  .article-layout {
    grid-template-columns: 1fr;
  }

  .article-toc {
    position: static;
  }

  .section-heading-with-visual {
    grid-template-columns: 1fr;
  }

  .section-visual {
    max-width: 420px;
  }

  .articles-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .principles-grid {
    grid-template-columns: 1fr;
  }

  .calculator-section {
    grid-template-columns: 1fr;
  }

  .calculator-result {
    position: static;
  }

  .glossary-group article {
    grid-template-columns: 1fr;
  }

  .glossary-group small {
    grid-column: auto;
  }
}

@media (max-width: 720px) {
  .site-header {
    align-items: flex-start;
  }

  .nav-toggle {
    display: block;
  }

  .site-nav {
    position: absolute;
    top: 70px;
    right: 20px;
    left: 20px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 10px;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: var(--white);
    box-shadow: var(--shadow);
  }

  .site-nav.is-open {
    display: flex;
  }

  .site-nav a {
    padding: 12px;
  }

  .hero {
    min-height: auto;
    padding-top: 48px;
  }

  h1 {
    font-size: 2.55rem;
  }

  .intro-band div,
  .site-footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .topic-grid {
    grid-template-columns: 1fr;
  }

  .roadmap-grid {
    grid-template-columns: 1fr;
  }

  .start-advice-grid {
    grid-template-columns: 1fr;
  }

  .article-list a {
    grid-template-columns: 90px 1fr;
    gap: 12px;
  }

  .article-list img {
    grid-row: span 2;
  }

  .article-list span {
    align-self: end;
  }

  .article-list strong {
    grid-column: 2;
  }

  .articles-grid {
    grid-template-columns: 1fr;
  }

  .calculator-form,
  .calc-metrics {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 420px) {
  .brand span:last-child {
    max-width: 190px;
    overflow-wrap: anywhere;
  }

  h1 {
    font-size: 2.15rem;
  }

  .hero-actions,
  .button {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}