/* ===== Aoyao Energy - Clean Energy Solutions ===== */
:root {
  --color-bg: #f3f4f6;
  --color-surface: #ffffff;
  --color-surface-alt: #f9fafb;
  --color-primary: #f59e0b;
  --color-primary-dim: #d97706;
  --color-accent: #0ea5e9;
  --color-text: #0f172a;
  --color-text-muted: #6b7280;
  --color-border: rgba(148, 163, 184, 0.4);
  --font-sans: 'Outfit', 'Noto Sans SC', system-ui, sans-serif;
  --font-sc: 'Noto Sans SC', 'Outfit', sans-serif;
  --radius: 12px;
  --radius-lg: 20px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.08);
  --transition: 0.25s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  overflow-x: hidden;
}

.container {
  width: 100%;
  max-width: 1140px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

/* ----- Lang bar ----- */
.lang-bar {
  background: #ffffff;
  border-bottom: 1px solid var(--color-border);
  padding: 6px 0;
  font-size: 0.875rem;
}

.lang-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.lang-email {
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition);
}

.lang-email:hover {
  color: var(--color-primary);
}

.lang-switch {
  display: flex;
  align-items: center;
  gap: 6px;
}

.lang-btn {
  background: none;
  border: none;
  color: var(--color-text-muted);
  cursor: pointer;
  font-size: 0.875rem;
  padding: 4px 8px;
  border-radius: 6px;
  transition: color var(--transition), background var(--transition);
}

.lang-btn:hover {
  color: var(--color-text);
}

.lang-btn.active {
  color: var(--color-primary);
  font-weight: 600;
}

.lang-divider {
  color: var(--color-border);
  font-weight: 300;
}

/* ----- Header ----- */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: #ffffff;
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 20px;
}

.logo {
  text-decoration: none;
  color: var(--color-text);
  display: flex;
  flex-direction: column;
  line-height: 1.2;
  background: #ffffff;
}

.logo-text {
  font-size: 1.35rem;
  font-weight: 700;
}

.logo-img {
  display: block;
  height: 44px;
  width: auto;
  object-fit: contain;
  background: #ffffff;
  filter: brightness(1.12) contrast(1.02);
}

.logo-sub {
  font-size: 0.7rem;
  color: var(--color-primary);
  font-weight: 500;
  letter-spacing: 0.03em;
  margin-top: -2px;
}

.nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-link {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: color var(--transition);
}

.nav-link:hover {
  color: var(--color-primary);
}

.nav-cta {
  color: var(--color-primary);
  padding: 8px 18px;
  border: 1px solid var(--color-primary);
  border-radius: var(--radius);
}

.nav-cta:hover {
  background: var(--color-primary);
  color: var(--color-bg);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 6px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav-toggle span {
  width: 24px;
  height: 2px;
  background: var(--color-text);
  border-radius: 1px;
  transition: var(--transition);
}

/* ----- Hero ----- */
.hero {
  position: relative;
  min-height: 85vh;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  padding: 64px 0 0;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 50% 0%, rgba(245, 158, 11, 0.1) 0%, transparent 50%),
    linear-gradient(180deg, var(--color-bg) 0%, var(--color-surface) 100%);
  pointer-events: none;
}

.hero-layout {
  position: relative;
  z-index: 1;
  flex: 1 1 auto;
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  gap: 48px;
  align-items: center;
  padding-bottom: 24px;
}

.hero-content {
  position: relative;
  z-index: 1;
}

.hero-tag {
  font-size: 0.875rem;
  color: var(--color-primary);
  font-weight: 500;
  letter-spacing: 0.08em;
  margin-bottom: 12px;
}

.hero-title {
  font-size: clamp(2rem, 4.5vw, 3.25rem);
  font-weight: 700;
  line-height: 1.22;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.hero-desc {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  line-height: 1.65;
  max-width: 520px;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: 24px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-bottom: 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 28px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius);
  text-decoration: none;
  transition: background var(--transition), color var(--transition), border-color var(--transition);
  cursor: pointer;
  border: 2px solid transparent;
  font-family: inherit;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

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

.btn-outline {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border);
}

.btn-outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn-block {
  width: 100%;
}

.hero-visual img {
  width: 100%;
  max-width: 480px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow);
  display: block;
}

.hero-scroll {
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 20px 0 28px;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.hero-scroll-arrow {
  animation: bounce 2s infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(6px); }
}

/* ----- Sections ----- */
.section {
  padding: 64px 0;
}

.section-head {
  text-align: center;
  max-width: 560px;
  margin: 0 auto 36px;
}

.section-label {
  display: inline-block;
  font-size: 0.8rem;
  color: var(--color-primary);
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 8px;
}

.section-title {
  font-size: clamp(1.65rem, 3.2vw, 2.15rem);
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 10px;
  letter-spacing: -0.02em;
}

.section-desc {
  color: var(--color-text-muted);
  font-size: 1rem;
  line-height: 1.65;
}

/* ----- Services cards ----- */
.section-services {
  background: var(--color-surface);
}

.section-services .section-head {
  margin-bottom: 32px;
}

.cards {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 20px;
}

.card {
  flex: 0 1 calc((100% - 40px) / 3);
  min-width: 260px;
}

.card {
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-primary);
  border-radius: var(--radius);
  padding: 20px 22px;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.card:hover {
  border-left-color: var(--color-primary-dim);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
}

.card-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 10px;
}

.card-icon {
  font-size: 1.5rem;
  line-height: 1;
  flex-shrink: 0;
}

.card-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 0;
  line-height: 1.3;
}

.card-text {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  line-height: 1.6;
  margin: 0;
}

/* ----- Locations ----- */
.section-locations {
  background: var(--color-bg);
}

.location-cities {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
}

.location-pill {
  padding: 10px 20px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-weight: 500;
  font-size: 0.95rem;
  color: var(--color-text);
}

.location-pill:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* ----- About ----- */
.section-about {
  background: var(--color-surface);
}

.about-inner {
  max-width: 720px;
  margin: 0 auto;
}

.about-content .section-label {
  margin-bottom: 12px;
}

.about-content .section-title {
  text-align: left;
  margin-bottom: 24px;
}

.about-text {
  color: var(--color-text-muted);
  margin-bottom: 16px;
  font-size: 1.05rem;
}

/* ----- Why us ----- */
.section-why {
  background: var(--color-surface);
}

.section-why .section-head {
  margin-bottom: 28px;
}

.section-why .section-label {
  display: block;
  text-align: center;
}

.section-why .section-title {
  text-align: center;
}

.why-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  max-width: 1000px;
  margin: 0 auto;
}

.why-item {
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-primary);
  border-radius: var(--radius);
  padding: 22px 20px;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.why-item:hover {
  border-left-color: var(--color-primary-dim);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
}

.why-num {
  display: block;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 8px;
  letter-spacing: 0.02em;
}

.why-title {
  font-size: 1.08rem;
  font-weight: 600;
  color: var(--color-text);
  margin: 0 0 8px 0;
  line-height: 1.35;
}

.why-text {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.6;
  margin: 0;
}

/* ----- Contact ----- */
.section-contact {
  background: var(--color-bg);
}

.contact-wrap {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 48px;
  align-items: start;
  max-width: 900px;
  margin: 0 auto;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.form-group label {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-muted);
}

.form-group input,
.form-group select,
.form-group textarea {
  padding: 12px 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  color: var(--color-text);
  font-family: inherit;
  font-size: 1rem;
  transition: border-color var(--transition);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: var(--color-text-muted);
  opacity: 0.8;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
}

.form-group textarea {
  resize: vertical;
  min-height: 100px;
}

.contact-info {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.contact-icon {
  font-size: 1.25rem;
}

.contact-item a {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: 500;
}

.contact-item a:hover {
  text-decoration: underline;
}

.contact-note {
  margin-top: 20px;
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

/* ----- Footer ----- */
.footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: 40px 0;
}

.footer-inner {
  text-align: center;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-bottom: 8px;
}

.footer-logo-img {
  display: block;
  height: 48px;
  width: auto;
  object-fit: contain;
  margin-bottom: 4px;
  background: transparent;
  filter: brightness(1.12) contrast(1.02);
}

.footer-brand .logo-sub {
  font-size: 0.85rem;
  color: var(--color-primary);
}

.footer-copy {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .card {
    flex: 0 1 calc((100% - 20px) / 2);
  }

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

@media (max-width: 768px) {
  .lang-bar .lang-email {
    font-size: 0.75rem;
  }

  .nav {
    position: fixed;
    top: 0;
    right: 0;
    width: 280px;
    height: 100vh;
    background: var(--color-surface);
    border-left: 1px solid var(--color-border);
    flex-direction: column;
    align-items: stretch;
    padding: 80px 24px 24px;
    gap: 0;
    transform: translateX(100%);
    transition: transform var(--transition);
    z-index: 99;
  }

  .nav.is-open {
    transform: translateX(0);
  }

  .nav-link {
    padding: 14px 0;
    border-bottom: 1px solid var(--color-border);
    font-size: 1rem;
  }

  .nav-cta {
    margin-top: 16px;
    text-align: center;
    border: 2px solid var(--color-primary);
  }

  .nav-toggle {
    display: flex;
    z-index: 101;
  }

  .nav-toggle.is-open span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
  }

  .nav-toggle.is-open span:nth-child(2) {
    opacity: 0;
  }

  .nav-toggle.is-open span:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
  }

  .hero {
    min-height: auto;
    padding: 40px 0 0;
  }

  .hero-layout {
    grid-template-columns: 1fr;
    gap: 28px;
    padding-bottom: 16px;
  }

  .hero-content {
    text-align: center;
  }

  .hero-tag,
  .hero-title,
  .hero-desc {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-actions {
    justify-content: center;
  }

  .hero-visual {
    order: -1;
    display: flex;
    justify-content: center;
  }

  .hero-visual img {
    max-width: 100%;
    margin: 0 auto;
  }

  .hero-scroll {
    padding: 16px 0 40px;
  }

  .section {
    padding: 56px 0;
  }

  .section-head {
    margin-bottom: 32px;
  }

  .card {
    flex: 0 1 100%;
  }

  .why-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .why-item {
    padding: 20px 18px;
  }

  .contact-wrap {
    grid-template-columns: 1fr;
  }

  .form-row {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .container {
    padding-left: 20px;
    padding-right: 20px;
  }

  .header-inner {
    padding: 12px 16px;
  }

  .logo-text {
    font-size: 1.2rem;
  }

  .hero-title {
    font-size: 1.75rem;
  }

  .hero-desc {
    font-size: 1rem;
  }

  .card {
    padding: 24px;
  }

  .contact-info {
    padding: 24px;
  }
}