:root {
  --bg: #0b0f14;
  --panel: #111821;
  --panel-2: #151f2b;
  --ink: #eef4fb;
  --muted: #93a4b8;
  --line: #263446;
  --blue: #2d6cff;
  --cyan: #45d7ff;
  --green: #42d392;
  --white: #ffffff;
  --danger: #ff5c77;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 20% 0%, rgba(45, 108, 255, 0.22), transparent 32rem),
    radial-gradient(circle at 90% 12%, rgba(69, 215, 255, 0.12), transparent 28rem),
    var(--bg);
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.5;
}

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

button,
input,
select {
  font: inherit;
}

.site-header {
  position: sticky;
  z-index: 10;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
  min-height: 74px;
  padding: 14px clamp(18px, 4vw, 56px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  background: rgba(11, 15, 20, 0.82);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
}

.brand img {
  width: 190px;
  height: 48px;
  object-fit: contain;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border: 1px solid rgba(69, 215, 255, 0.5);
  border-radius: 8px;
  color: var(--cyan);
  background: rgba(69, 215, 255, 0.08);
  font-weight: 900;
}

.brand strong,
.brand small {
  display: block;
}

.brand small {
  color: var(--muted);
  font-size: 12px;
}

.nav {
  display: flex;
  gap: 24px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 800;
}

.nav a:hover {
  color: var(--ink);
}

.header-link,
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid transparent;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 900;
  cursor: pointer;
}

.header-link,
.button.secondary {
  border-color: rgba(255, 255, 255, 0.16);
  color: var(--ink);
  background: rgba(255, 255, 255, 0.05);
}

.button.primary {
  color: var(--white);
  background: linear-gradient(135deg, var(--blue), #1b4bc8);
  box-shadow: 0 18px 38px rgba(45, 108, 255, 0.25);
}

.button.has-badge {
  position: relative;
  padding-right: 26px;
}

.button.has-badge::after {
  content: "aktivní";
  position: absolute;
  top: -9px;
  right: -9px;
  padding: 3px 7px;
  border: 1px solid rgba(250, 204, 21, 0.58);
  border-radius: 999px;
  color: #2b1d00;
  background: #facc15;
  font-size: 9px;
  font-weight: 900;
  line-height: 1;
  text-transform: none;
}

.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(320px, 0.65fr);
  gap: clamp(28px, 5vw, 76px);
  min-height: 760px;
  padding: 110px clamp(18px, 5vw, 72px) 86px;
  align-items: center;
  overflow: hidden;
}

.hero-grid {
  position: absolute;
  inset: 0;
  opacity: 0.2;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.12) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.12) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: linear-gradient(to bottom, #000, transparent 82%);
}

.hero-content,
.hero-panel {
  position: relative;
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--cyan);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0;
  text-transform: uppercase;
}

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

h1 {
  max-width: 900px;
  margin-bottom: 24px;
  font-size: clamp(44px, 7vw, 94px);
  line-height: 0.92;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 0;
  font-size: clamp(32px, 4vw, 56px);
  line-height: 1.03;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 10px;
  font-size: 22px;
}

.hero-content p:not(.eyebrow) {
  max-width: 720px;
  color: var(--muted);
  font-size: 20px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.hero-panel {
  padding: 28px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 8px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.03));
  box-shadow: 0 24px 80px rgba(0, 0, 0, 0.36);
}

.hero-panel img {
  width: 100%;
  max-height: 124px;
  margin-bottom: 24px;
  object-fit: contain;
  filter: invert(1);
}

.steng-panel h2 {
  margin-bottom: 14px;
  font-size: clamp(26px, 3vw, 40px);
}

.steng-panel p {
  color: var(--muted);
}

.steng-panel .button {
  width: 100%;
  margin-top: 10px;
}

.panel-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 18px 0;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.panel-row span,
.panel-note,
.section-heading p,
.tool-item small,
.calculator-head p,
.formula,
.roadmap span,
.calc-status span {
  color: var(--muted);
}

.panel-row strong {
  font-size: 30px;
}

.panel-note {
  padding-top: 18px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font-size: 13px;
}

.section {
  padding: 88px clamp(18px, 5vw, 72px);
}

.section-heading,
.calculator-head,
.roadmap {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 0.62fr);
  gap: clamp(28px, 5vw, 72px);
  align-items: end;
}

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

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

.tool-column {
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(17, 24, 33, 0.82);
}

.tool-column-head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 18px;
}

.tool-column h3 {
  margin-bottom: 0;
  color: var(--ink);
  font-size: 24px;
}

.category-icon {
  position: relative;
  display: grid;
  place-items: center;
  width: 54px;
  height: 54px;
  flex: 0 0 auto;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 8px;
  color: var(--white);
  font-size: 20px;
  font-weight: 900;
  overflow: hidden;
}

.category-icon::before,
.category-icon::after {
  content: "";
  position: absolute;
  inset: 10px;
  opacity: 0.34;
  pointer-events: none;
}

.category-icon.concrete {
  background: linear-gradient(135deg, #52616f, #1f2933);
}

.category-icon.concrete::before {
  inset: 13px 8px auto;
  height: 12px;
  border-radius: 2px;
  background: rgba(255, 255, 255, 0.92);
  clip-path: none;
}

.category-icon.concrete::after {
  inset: 22px 21px 10px;
  height: auto;
  border: 0;
  border-radius: 1px;
  background: rgba(255, 255, 255, 0.88);
  clip-path: none;
}

.category-icon.steel {
  background: linear-gradient(135deg, #1d4ed8, #0f172a);
}

.category-icon.steel::before {
  inset: 11px 23px;
  border-radius: 1px;
  background: rgba(255, 255, 255, 0.9);
}

.category-icon.steel::after {
  inset: 10px 9px;
  border-top: 8px solid rgba(255, 255, 255, 0.9);
  border-bottom: 8px solid rgba(255, 255, 255, 0.9);
  border-radius: 1px;
}

.category-icon.wood {
  background: linear-gradient(135deg, #9a6a35, #312313);
}

.category-icon.wood::before {
  border: 2px solid rgba(255, 255, 255, 0.65);
  border-radius: 50%;
}

.category-icon.wood::after {
  inset: 18px;
  border: 2px solid rgba(255, 255, 255, 0.55);
  border-radius: 50%;
}

.category-icon.foundation {
  background: linear-gradient(135deg, #1f8a70, #11251f);
}

.category-icon.foundation::before {
  inset: auto 10px 11px;
  height: 12px;
  background: rgba(255, 255, 255, 0.8);
  clip-path: polygon(12% 0, 88% 0, 100% 100%, 0 100%);
}

.category-icon.foundation::after {
  inset: 12px 18px auto;
  height: 24px;
  border-left: 4px solid rgba(255, 255, 255, 0.72);
  border-right: 4px solid rgba(255, 255, 255, 0.72);
}

.tool-item {
  display: grid;
  gap: 6px;
  min-height: 104px;
  padding: 16px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.035);
}

.tool-item + .tool-item {
  margin-top: 12px;
}

.tool-item.active {
  border-color: rgba(69, 215, 255, 0.42);
  background: linear-gradient(180deg, rgba(45, 108, 255, 0.18), rgba(17, 24, 33, 0.86));
}

.tool-item span {
  color: var(--cyan);
  font-size: 12px;
  font-weight: 900;
}

.tool-item strong,
.tool-item small {
  display: block;
}

.tool-item.muted {
  opacity: 0.68;
}

.tool-item.muted strong {
  color: #cbd6e4;
}

.tool-item.active:hover {
  border-color: var(--cyan);
}

.tool-item small {
  font-size: 13px;
}

.tool-item.active::after {
  content: "Použít";
  color: var(--cyan);
  font-weight: 900;
}

.calculator {
  background: rgba(255, 255, 255, 0.03);
}

.cover-tool {
  background:
    linear-gradient(180deg, rgba(17, 24, 33, 0.64), rgba(11, 15, 20, 0.88)),
    rgba(255, 255, 255, 0.02);
}

.calculator-head {
  margin-bottom: 26px;
}

.calc-status {
  justify-self: end;
  display: grid;
  gap: 4px;
  min-width: 260px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
}

.calc-status strong {
  color: var(--cyan);
}

.tool-controls {
  display: grid;
  grid-template-columns: minmax(320px, 1fr) 130px minmax(160px, 220px) minmax(170px, 210px) 150px 150px;
  gap: 14px;
  align-items: end;
  margin-bottom: 16px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(17, 24, 33, 0.82);
}

.segmented {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  min-height: 44px;
  padding: 3px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #0d141d;
}

.segmented button {
  border: 0;
  border-radius: 6px;
  color: var(--muted);
  background: transparent;
  font-weight: 900;
  cursor: pointer;
}

.segmented button.is-active {
  color: var(--white);
  background: var(--blue);
}

.tool-controls label {
  display: grid;
  gap: 7px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 900;
  text-transform: uppercase;
}

.cover-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(320px, 0.85fr);
  gap: 22px;
  align-items: start;
}

.cover-form {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(17, 24, 33, 0.82);
}

.cover-form label {
  display: grid;
  gap: 7px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 900;
  text-transform: uppercase;
}

.cover-results {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.cover-results article {
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel-2);
}

.cover-results .main-result {
  grid-column: 1 / -1;
  border-color: rgba(69, 215, 255, 0.42);
  background: linear-gradient(180deg, rgba(45, 108, 255, 0.18), rgba(17, 24, 33, 0.86));
}

.cover-results span {
  display: block;
  margin-bottom: 8px;
  color: var(--muted);
  font-size: 13px;
}

.cover-results strong {
  font-size: 30px;
}

.cover-results .main-result strong {
  color: var(--cyan);
  font-size: 54px;
  line-height: 1;
}

.tool-controls .toggle {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #0d141d;
  text-transform: none;
}

.toggle input {
  width: 18px;
  min-height: 18px;
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
}

.rebar-matrix {
  width: 100%;
  min-width: 820px;
  border-collapse: collapse;
}

.rebar-matrix th,
.rebar-matrix td {
  padding: 14px;
  border-bottom: 1px solid var(--line);
  text-align: left;
}

.rebar-matrix thead th {
  color: var(--muted);
  background: #162231;
  font-size: 12px;
  text-transform: uppercase;
}

.rebar-matrix tbody th {
  color: #061016;
  background: #80ff80;
  font-weight: 900;
}

.rebar-matrix td {
  color: var(--ink);
  background: #ffffff;
  color: #061016;
  text-align: right;
  cursor: pointer;
}

.rebar-matrix td:nth-child(2) {
  background: #f3f6fa;
  cursor: default;
}

.rebar-matrix td.is-under {
  background: #ffffc0;
}

.rebar-matrix td.is-over {
  background: #c0ffff;
}

.rebar-matrix td.is-exact {
  background: #ffff00;
  font-weight: 900;
}

select,
input {
  width: 100%;
  min-height: 42px;
  padding: 8px 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--ink);
  background: #0d141d;
}

.remove-row {
  min-width: 40px;
  min-height: 40px;
  border: 1px solid rgba(255, 92, 119, 0.4);
  border-radius: 6px;
  color: var(--danger);
  background: rgba(255, 92, 119, 0.08);
  cursor: pointer;
}

.legend {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 18px;
}

.legend article {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 4px 12px;
  align-items: center;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel-2);
}

.legend span:last-child {
  grid-column: 2;
  color: var(--muted);
  font-size: 13px;
}

.swatch {
  width: 24px;
  height: 24px;
  border-radius: 4px;
}

.swatch.under {
  background: #ffffc0;
}

.swatch.over {
  background: #c0ffff;
}

.swatch.exact {
  background: #ffff00;
}

.formula {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 24px;
  margin-top: 18px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(17, 24, 33, 0.6);
}

.formula strong {
  color: var(--ink);
}

.cover-formula {
  display: grid;
}

.cover-formula code {
  display: block;
  width: 100%;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: #dfeaff;
  background: #0d141d;
  font-family: Consolas, "Courier New", monospace;
  font-size: 13px;
  line-height: 1.55;
  white-space: pre-wrap;
}

.roadmap {
  align-items: start;
}

.roadmap ol {
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.roadmap li {
  display: grid;
  gap: 4px;
  padding: 20px;
  border-left: 4px solid var(--blue);
  background: var(--panel);
}

.mastermind {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(320px, 0.72fr);
  gap: clamp(28px, 5vw, 72px);
  align-items: center;
  background:
    radial-gradient(circle at 78% 22%, rgba(69, 215, 255, 0.16), transparent 24rem),
    rgba(255, 255, 255, 0.025);
}

.mastermind-copy p:not(.eyebrow) {
  max-width: 660px;
  margin-top: 22px;
  color: var(--muted);
  font-size: 20px;
}

.mastermind-photo {
  width: 100%;
  margin-top: 24px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 8px;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  box-shadow: 0 24px 80px rgba(0, 0, 0, 0.28);
}

.membership-card {
  padding: 28px;
  border: 1px solid rgba(69, 215, 255, 0.28);
  border-radius: 8px;
  background: linear-gradient(180deg, rgba(45, 108, 255, 0.16), rgba(17, 24, 33, 0.92));
  box-shadow: 0 24px 80px rgba(0, 0, 0, 0.34);
}

.price {
  display: grid;
  gap: 2px;
  margin-bottom: 18px;
}

.price span,
.price small,
.membership-card p,
.membership-card li {
  color: var(--muted);
}

.price strong {
  color: var(--cyan);
  font-size: clamp(48px, 6vw, 76px);
  line-height: 0.95;
}

.membership-card ul {
  display: grid;
  gap: 10px;
  margin: 22px 0;
  padding: 0;
  list-style: none;
}

.membership-includes {
  margin-top: 22px;
  padding: 18px;
  border: 1px solid rgba(69, 215, 255, 0.24);
  border-radius: 8px;
  background: rgba(69, 215, 255, 0.07);
}

.membership-includes strong,
.membership-subtitle {
  display: block;
  color: var(--ink);
}

.membership-includes ul {
  margin-bottom: 0;
}

.membership-subtitle {
  margin-top: 22px;
}

.membership-card li {
  position: relative;
  padding-left: 24px;
}

.membership-card li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.7em;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--cyan);
}

.membership-card .button {
  width: 100%;
}

.membership-contact {
  margin-top: 18px;
}

.membership-contact a {
  color: var(--cyan);
  font-weight: 900;
}

.footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 28px clamp(18px, 5vw, 72px);
  color: var(--muted);
  border-top: 1px solid var(--line);
}

.footer-info {
  display: grid;
  gap: 4px;
}

.footer-info strong {
  color: var(--ink);
}

.footer-info a {
  color: var(--cyan);
  font-weight: 800;
}

.footer img {
  width: 220px;
  max-height: 52px;
  object-fit: contain;
  filter: invert(1);
}

@media (max-width: 1040px) {
  .nav {
    display: none;
  }

  .hero,
  .section-heading,
  .calculator-head,
  .cover-grid,
  .mastermind,
  .roadmap {
    grid-template-columns: 1fr;
  }

  .calculator-head .button {
    justify-self: start;
  }

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

  .segmented {
    grid-column: 1 / -1;
  }
}

@media (max-width: 680px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .header-link {
    width: 100%;
  }

  .hero {
    min-height: auto;
    padding: 64px 18px 58px;
  }

  h1 {
    font-size: 46px;
  }

  .section {
    padding: 64px 18px;
  }

  .tool-columns,
  .legend,
  .cover-form,
  .cover-results,
  .tool-controls,
  .segmented {
    grid-template-columns: 1fr;
  }

  .footer {
    align-items: flex-start;
    flex-direction: column;
  }
}