/* ==========================================================================
   TankFlexi — Design Tokens
   ========================================================================== */
:root {
  --color-charcoal: #3d454b;
  --color-charcoal-dark: #2a3034;
  --color-charcoal-darker: #1c2124;
  --color-lime: #abd233;
  --color-lime-dark: #8fb524;
  --color-off-white: #f5f6f3;
  --color-white: #ffffff;
  --color-ink: #21262a;
  --color-muted: #6b7378;
  --color-border: #e2e4df;

  --font-heading: "Space Grotesk", "Helvetica Neue", Arial, sans-serif;
  --font-body: "Inter", "Helvetica Neue", Arial, sans-serif;

  --container-w: 1240px;
  --nav-h: 88px;
  --nav-h-mobile: 72px;

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 24px;

  --shadow-sm: 0 2px 10px rgba(28, 33, 36, 0.06);
  --shadow-md: 0 12px 32px rgba(28, 33, 36, 0.12);

  --ease: cubic-bezier(0.4, 0, 0.2, 1);
}

/* ==========================================================================
   Reset & Base
   ========================================================================== */
* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-h);
}

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--color-ink);
  background: var(--color-off-white);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

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

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

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

h1,
h2,
h3,
h4 {
  font-family: var(--font-heading);
  font-weight: 600;
  line-height: 1.1;
  margin: 0 0 0.5em;
  letter-spacing: -0.01em;
}

h1 {
  font-size: clamp(2.6rem, 5vw, 4.6rem);
}

h2 {
  font-size: clamp(1.9rem, 3.2vw, 2.8rem);
}

h3 {
  font-size: clamp(1.25rem, 2vw, 1.5rem);
}

p {
  margin: 0 0 1em;
  line-height: 1.65;
  color: var(--color-muted);
}

.container {
  width: 100%;
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 0 32px;
}

.section {
  padding: 110px 0;
}

.section--tight {
  padding: 72px 0;
}

.section--dark {
  background: var(--color-charcoal);
  color: var(--color-white);
}

.section--dark p {
  color: rgba(245, 246, 243, 0.72);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-heading);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-lime-dark);
  margin-bottom: 18px;
}

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

.eyebrow::before {
  content: "";
  width: 26px;
  height: 2px;
  background: currentColor;
}

.section-head {
  max-width: 680px;
  margin-bottom: 56px;
}

.section-head--center {
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}

/* ==========================================================================
   Buttons
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 15px 30px;
  border-radius: 999px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.01em;
  border: 1.5px solid transparent;
  cursor: pointer;
  transition: transform 0.25s var(--ease), background 0.25s var(--ease), color 0.25s var(--ease), border-color 0.25s var(--ease);
}

.btn:hover {
  transform: translateY(-2px);
}

.btn-primary {
  background: var(--color-lime);
  color: var(--color-charcoal-darker);
}

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

.btn-outline {
  background: transparent;
  color: var(--color-white);
  border-color: rgba(245, 246, 243, 0.4);
}

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

.btn-dark {
  background: var(--color-charcoal-darker);
  color: var(--color-white);
}

.btn-dark:hover {
  background: var(--color-charcoal);
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

/* ==========================================================================
   Navigation
   ========================================================================== */
.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-h);
  z-index: 100;
  background: var(--color-charcoal-darker);
  display: flex;
  align-items: center;
  transition: box-shadow 0.3s var(--ease), height 0.3s var(--ease);
}

.site-nav.is-scrolled {
  box-shadow: var(--shadow-md);
}

.site-nav__inner {
  width: 100%;
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 0 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-nav__logo img {
  height: 34px;
  width: auto;
}

.site-nav__menu {
  display: flex;
  align-items: center;
  gap: 40px;
}

.site-nav__menu a {
  font-family: var(--font-heading);
  font-size: 0.92rem;
  font-weight: 500;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  color: rgba(245, 246, 243, 0.82);
  position: relative;
  padding: 6px 0;
  transition: color 0.2s var(--ease);
}

.site-nav__menu a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  background: var(--color-lime);
  transition: width 0.25s var(--ease);
}

.site-nav__menu a:hover,
.site-nav__menu a.is-active {
  color: var(--color-white);
}

.site-nav__menu a:hover::after,
.site-nav__menu a.is-active::after {
  width: 100%;
}

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

.site-nav__toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: transparent;
  border: none;
  cursor: pointer;
  z-index: 101;
}

.site-nav__toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--color-white);
  transition: transform 0.3s var(--ease), opacity 0.3s var(--ease);
}

body.nav-open .site-nav__toggle span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

body.nav-open .site-nav__toggle span:nth-child(2) {
  opacity: 0;
}

body.nav-open .site-nav__toggle span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ==========================================================================
   Hero
   ========================================================================== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: radial-gradient(ellipse at 70% 30%, #454e55 0%, var(--color-charcoal-darker) 62%);
  color: var(--color-white);
  overflow: hidden;
}

.hero__media {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.hero__media video,
.hero__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.55;
}

.hero__media::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(28, 33, 36, 0.35) 0%, rgba(28, 33, 36, 0.85) 100%);
}

.hero__content {
  position: relative;
  z-index: 1;
  padding-top: var(--nav-h);
  max-width: 760px;
}

.hero__content h1 {
  margin-bottom: 0.3em;
}

.hero__content h1 .accent {
  color: var(--color-lime);
}

.hero__lede {
  font-size: 1.15rem;
  color: rgba(245, 246, 243, 0.78);
  max-width: 560px;
  margin-bottom: 2.2em;
}

.hero__stats {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  margin-top: 90px;
  padding-top: 36px;
  border-top: 1px solid rgba(245, 246, 243, 0.16);
}

.hero__stat-label {
  font-family: var(--font-heading);
  font-size: 0.82rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-lime);
  margin-bottom: 6px;
}

.hero__stat-value {
  font-size: 0.95rem;
  color: rgba(245, 246, 243, 0.7);
}

/* ==========================================================================
   Page header (non-hero sub-pages)
   ========================================================================== */
.page-header {
  position: relative;
  background: var(--color-charcoal-darker);
  color: var(--color-white);
  padding: calc(var(--nav-h) + 64px) 0 72px;
  overflow: hidden;
}

.page-header p {
  max-width: 620px;
  font-size: 1.05rem;
}

.page-header__media {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.page-header__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.5;
}

.page-header__media::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(28, 33, 36, 0.55) 0%, rgba(28, 33, 36, 0.94) 100%);
}

.page-header .container {
  position: relative;
  z-index: 1;
}

/* ==========================================================================
   Cards & Grids
   ========================================================================== */
.grid {
  display: grid;
  gap: 32px;
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

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

.card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 36px 32px;
  transition: transform 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.card__icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-sm);
  background: rgba(171, 210, 51, 0.15);
  color: var(--color-lime-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 22px;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.1rem;
}

.card--dark {
  background: var(--color-charcoal);
  border-color: var(--color-charcoal);
  color: var(--color-white);
}

.card--dark p {
  color: rgba(245, 246, 243, 0.72);
}

.card--dark .card__icon {
  background: rgba(171, 210, 51, 0.2);
}

/* ==========================================================================
   Split section (image + text)
   ========================================================================== */
.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 72px;
  align-items: center;
}

.split--reverse .split__media {
  order: 2;
}

.split__media img {
  border-radius: var(--radius-lg);
  width: 100%;
}

.split__media--framed {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-charcoal-darker);
}

.split__media--framed img {
  border-radius: 0;
  opacity: 0.94;
}

/* ==========================================================================
   Feature list (checkmark style)
   ========================================================================== */
.feature-list li {
  display: flex;
  gap: 14px;
  padding: 14px 0;
  border-bottom: 1px solid var(--color-border);
}

.section--dark .feature-list li {
  border-color: rgba(245, 246, 243, 0.14);
}

.feature-list li:last-child {
  border-bottom: none;
}

.feature-list__mark {
  flex: none;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--color-lime);
  color: var(--color-charcoal-darker);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  margin-top: 2px;
}

.feature-list strong {
  display: block;
  font-family: var(--font-heading);
  font-weight: 600;
  margin-bottom: 2px;
  color: var(--color-ink);
}

.section--dark .feature-list strong {
  color: var(--color-white);
}

.feature-list span {
  color: var(--color-muted);
  font-size: 0.96rem;
}

.section--dark .feature-list span {
  color: rgba(245, 246, 243, 0.68);
}

/* ==========================================================================
   Product tabs (A / B / C type)
   Progressive enhancement: panels stack and are all visible with no JS;
   main.js adds .is-tabbed to switch to a tabbed, deep-linkable view.
   ========================================================================== */
.product-tabs__nav {
  display: none;
  gap: 14px;
  margin-bottom: 48px;
  flex-wrap: wrap;
}

.product-tabs.is-tabbed .product-tabs__nav {
  display: flex;
}

.product-tabs__nav button {
  padding: 14px 28px;
  border-radius: 999px;
  border: 1.5px solid var(--color-border);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.25s var(--ease);
  background: var(--color-white);
  color: var(--color-ink);
}

.product-tabs__nav button.is-active {
  background: var(--color-charcoal-darker);
  border-color: var(--color-charcoal-darker);
  color: var(--color-lime);
}

.product-tabs__panel {
  scroll-margin-top: calc(var(--nav-h) + 24px);
  margin-bottom: 96px;
}

.product-tabs__panel:last-child {
  margin-bottom: 0;
}

.product-tabs.is-tabbed .product-tabs__panel {
  display: none;
  margin-bottom: 0;
  animation: fade-up 0.5s var(--ease);
}

.product-tabs.is-tabbed .product-tabs__panel.is-active {
  display: block;
}

.product-tabs__panel-head {
  margin-bottom: 32px;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--color-border);
}

.product-tabs.is-tabbed .product-tabs__panel-head {
  display: none;
}

@keyframes fade-up {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.spec-grid {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 48px;
  align-items: start;
}

.spec-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--color-white);
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--color-border);
}

.spec-table th,
.spec-table td {
  text-align: left;
  padding: 16px 22px;
  font-size: 0.95rem;
  border-bottom: 1px solid var(--color-border);
}

.spec-table tr:last-child th,
.spec-table tr:last-child td {
  border-bottom: none;
}

.spec-table th {
  width: 42%;
  font-family: var(--font-heading);
  font-weight: 600;
  color: var(--color-ink);
  background: var(--color-off-white);
}

.spec-table td {
  color: var(--color-muted);
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 28px;
}

.tag {
  padding: 8px 16px;
  border-radius: 999px;
  background: rgba(171, 210, 51, 0.14);
  color: var(--color-lime-dark);
  font-size: 0.85rem;
  font-weight: 600;
  font-family: var(--font-heading);
}

/* ==========================================================================
   Purchasing / forms
   ========================================================================== */
.info-panel {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 32px;
}

.info-panel + .info-panel {
  margin-top: 24px;
}

.form-panel {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  padding: 44px;
  box-shadow: var(--shadow-md);
}

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

.form-field {
  margin-bottom: 20px;
}

.form-field label {
  display: block;
  font-family: var(--font-heading);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--color-ink);
}

.form-field input,
.form-field select,
.form-field textarea {
  width: 100%;
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  border: 1.5px solid var(--color-border);
  font-family: var(--font-body);
  font-size: 0.96rem;
  background: var(--color-off-white);
  transition: border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.form-field input:focus,
.form-field select:focus,
.form-field textarea:focus {
  outline: none;
  border-color: var(--color-lime-dark);
  background: var(--color-white);
}

.form-field textarea {
  resize: vertical;
  min-height: 130px;
}

.form-alert {
  padding: 16px 20px;
  border-radius: var(--radius-sm);
  margin-bottom: 28px;
  font-size: 0.95rem;
  font-weight: 500;
}

.form-alert--success {
  background: rgba(171, 210, 51, 0.16);
  color: #567113;
}

.form-alert--error {
  background: #fde3e0;
  color: #a13a2c;
}

/* ==========================================================================
   CTA band
   ========================================================================== */
.cta-band {
  background: var(--color-charcoal-darker);
  color: var(--color-white);
  border-radius: var(--radius-lg);
  padding: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
}

.cta-band h2 {
  margin: 0;
  max-width: 460px;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer {
  background: var(--color-charcoal-darker);
  color: rgba(245, 246, 243, 0.7);
  padding: 80px 0 32px;
}

.site-footer__top {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 56px;
  border-bottom: 1px solid rgba(245, 246, 243, 0.12);
}

.site-footer__logo img {
  height: 32px;
  margin-bottom: 18px;
}

.site-footer__desc {
  max-width: 320px;
  font-size: 0.92rem;
}

.site-footer h4 {
  color: var(--color-white);
  font-size: 0.85rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 20px;
}

.site-footer li {
  margin-bottom: 12px;
  font-size: 0.92rem;
}

.site-footer a:hover {
  color: var(--color-lime);
}

.site-footer__bottom {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  padding-top: 28px;
  font-size: 0.82rem;
}

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (max-width: 991px) {
  :root {
    --nav-h: var(--nav-h-mobile);
  }

  .site-nav__toggle {
    display: flex;
  }

  .site-nav__menu {
    position: fixed;
    top: var(--nav-h-mobile);
    left: 0;
    right: 0;
    bottom: 0;
    flex-direction: column;
    align-items: flex-start;
    justify-content: flex-start;
    gap: 6px;
    background: var(--color-charcoal-darker);
    padding: 28px 32px;
    transform: translateX(100%);
    transition: transform 0.35s var(--ease);
  }

  body.nav-open .site-nav__menu {
    transform: translateX(0);
  }

  .site-nav__menu a {
    width: 100%;
    padding: 16px 0;
    font-size: 1.05rem;
    border-bottom: 1px solid rgba(245, 246, 243, 0.1);
  }

  .site-nav__cta .btn-primary {
    display: none;
  }

  .site-nav__menu .btn-primary {
    display: inline-flex;
    margin-top: 20px;
  }

  .section {
    padding: 76px 0;
  }

  .hero__stats {
    grid-template-columns: 1fr;
    gap: 20px;
    margin-top: 56px;
  }

  .grid-3 {
    grid-template-columns: 1fr 1fr;
  }

  .split,
  .spec-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .split--reverse .split__media {
    order: 0;
  }

  .site-footer__top {
    grid-template-columns: 1fr 1fr;
  }

  .cta-band {
    flex-direction: column;
    align-items: flex-start;
    padding: 44px;
  }
}

@media (max-width: 640px) {
  .container {
    padding: 0 20px;
  }

  .grid-3,
  .grid-2 {
    grid-template-columns: 1fr;
  }

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

  .form-panel {
    padding: 28px;
  }

  .cta-band {
    padding: 32px 24px;
  }

  .site-footer__top {
    grid-template-columns: 1fr;
  }

  .product-tabs__nav {
    gap: 10px;
  }

  .product-tabs__nav label {
    padding: 12px 20px;
    font-size: 0.9rem;
  }
}