/* ============================================================
   Cartbeat — pre-launch landing page
   Mobile-first, žádné externí závislosti, systémový font stack
   ============================================================ */

:root {
  --accent: #e5484d;          /* pulzní červená */
  --accent-dark: #cf3a3f;
  --accent-soft: #fdecec;     /* jemné pozadí pro odznaky */
  --ink: #16181d;             /* hlavní text */
  --ink-soft: #4b5260;        /* sekundární text */
  --bg: #ffffff;
  --bg-alt: #f8f9fb;          /* střídání sekcí */
  --line: #e6e8ee;
  --radius: 10px;
  --max-width: 1080px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.25rem;
}

.container.narrow {
  max-width: 720px;
}

h1, h2, h3 {
  line-height: 1.2;
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  margin-bottom: 1rem;
}

h3 {
  font-size: 1.1rem;
  margin-bottom: 0.35rem;
}

a {
  color: var(--accent);
}

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

/* ===== Hlavička ===== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 0.75rem;
  padding-bottom: 0.75rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  text-decoration: none;
  color: var(--ink);
}

.brand-mark {
  width: 30px;
  height: 30px;
  flex-shrink: 0;
}

.brand-name {
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: -0.01em;
}

.header-cta {
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  color: var(--accent);
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--accent);
  border-radius: 999px;
  transition: background 0.15s, color 0.15s;
}

.header-cta:hover {
  background: var(--accent);
  color: #fff;
}

/* ===== Hero ===== */

.hero {
  text-align: center;
  padding: 4.5rem 0 0;
  overflow: hidden;
  background: var(--ink);
  color: #fff;
}

.hero-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  margin-bottom: 1.75rem;
}

.hero-brand-mark {
  width: clamp(52px, 9vw, 76px);
  height: clamp(52px, 9vw, 76px);
  flex-shrink: 0;
}

.hero-brand-name {
  font-size: clamp(2.8rem, 9vw, 4.6rem);
  font-weight: 800;
  letter-spacing: -0.035em;
  color: #fff;
  line-height: 1;
}

.hero h1 {
  font-size: clamp(1.5rem, 4.2vw, 2.3rem);
  font-weight: 600;
  margin-bottom: 1.1rem;
  color: #fff;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: #fff;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 999px;
  padding: 0.35rem 0.9rem;
  margin-top: 1.75rem;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  animation: pulse 1.4s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 1; }
  50%      { transform: scale(1.45); opacity: 0.55; }
}

.hero-sub {
  max-width: 620px;
  margin: 0 auto 2.25rem;
  font-size: 1.1rem;
  color: rgba(255, 255, 255, 0.75);
}

.hero-sub strong {
  color: #fff;
}

/* Formulář a poznámka v tmavém hero — stejný styl jako spodní CTA */
.hero .waitlist-form input[type="email"] {
  border-color: transparent;
}

.hero .form-note {
  color: rgba(255, 255, 255, 0.55);
}

.hero .form-feedback.error {
  color: #ffb3b5;
}

.hero .form-success {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

/* ===== Formulář ===== */

.waitlist-form {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  max-width: 460px;
  margin: 0 auto;
}

.waitlist-form input[type="email"] {
  font: inherit;
  padding: 0.85rem 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  color: var(--ink);
  width: 100%;
}

.waitlist-form input[type="email"]:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
  border-color: var(--accent);
}

.waitlist-form button {
  font: inherit;
  font-weight: 700;
  color: #fff;
  background: var(--accent);
  border: none;
  border-radius: var(--radius);
  padding: 0.85rem 1.4rem;
  cursor: pointer;
  transition: background 0.15s, transform 0.1s;
  white-space: nowrap;
}

.waitlist-form button:hover {
  background: var(--accent-dark);
}

.waitlist-form button:active {
  transform: scale(0.98);
}

.waitlist-form button:disabled {
  opacity: 0.65;
  cursor: default;
}

.form-note {
  max-width: 460px;
  margin: 0.7rem auto 0;
  font-size: 0.78rem;
  color: var(--ink-soft);
}

.form-feedback {
  font-size: 0.9rem;
  text-align: left;
}

.form-feedback.error {
  color: var(--accent-dark);
}

.form-success {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--ink);
  background: var(--accent-soft);
  border-radius: var(--radius);
  padding: 0.85rem 1.4rem;
  width: 100%;
}

.form-success svg {
  width: 20px;
  height: 20px;
  color: var(--accent);
  flex-shrink: 0;
}

/* ===== EKG linka ===== */

.ekg-wrap {
  margin-top: 3.5rem;
}

.ekg {
  display: block;
  width: 100%;
  height: 90px;
}

.ekg-line {
  stroke-dasharray: 6 3;
  animation: ekg-flow 2.4s linear infinite;
}

@keyframes ekg-flow {
  to { stroke-dashoffset: -90; }
}

@media (prefers-reduced-motion: reduce) {
  .ekg-line, .pulse-dot {
    animation: none;
  }
  html {
    scroll-behavior: auto;
  }
}

/* ===== Problém ===== */

.problem {
  padding: 4.5rem 0;
}

.problem h2 {
  margin-bottom: 1.25rem;
}

.problem > .container > p {
  color: var(--ink-soft);
  font-size: 1.05rem;
  max-width: 620px;
}

.problem-points {
  margin-top: 2.5rem;
  display: grid;
  gap: 1.25rem;
}

.problem-point {
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 1.25rem 1.4rem;
  background: var(--bg);
}

.problem-point p {
  color: var(--ink-soft);
  font-size: 0.95rem;
}

/* ===== Jak to funguje ===== */

.how {
  padding: 4.5rem 0;
  background: var(--bg-alt);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.how h2 {
  text-align: center;
  margin-bottom: 2.5rem;
}

.steps {
  list-style: none;
  display: grid;
  gap: 1.5rem;
}

.step {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.75rem 1.5rem;
}

.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  font-size: 1rem;
  margin-bottom: 0.9rem;
}

.step p {
  color: var(--ink-soft);
  font-size: 0.95rem;
}

/* ===== Pro koho ===== */

.who {
  padding: 4.5rem 0;
}

.who-lead {
  color: var(--ink-soft);
  font-size: 1.05rem;
  margin-bottom: 1.75rem;
}

.who-list {
  list-style: none;
  display: grid;
  gap: 0.9rem;
}

.who-list li {
  display: flex;
  align-items: flex-start;
  gap: 0.7rem;
}

.who-list .check {
  width: 20px;
  height: 20px;
  color: var(--accent);
  flex-shrink: 0;
  margin-top: 0.2rem;
}

.who-list span {
  color: var(--ink-soft);
}

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

/* ===== Druhé CTA ===== */

.cta {
  padding: 4.5rem 0;
  text-align: center;
  background: var(--ink);
  color: #fff;
}

.cta h2 {
  color: #fff;
}

.cta-sub {
  color: rgba(255, 255, 255, 0.75);
  margin-bottom: 2rem;
}

.cta .waitlist-form input[type="email"] {
  border-color: transparent;
}

.cta .form-note {
  color: rgba(255, 255, 255, 0.55);
}

.cta .form-feedback.error {
  color: #ffb3b5;
}

.cta .form-success {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

/* ===== Patička ===== */

.site-footer {
  padding: 2rem 0;
  border-top: 1px solid var(--line);
}

.footer-inner {
  text-align: center;
  font-size: 0.85rem;
  color: var(--ink-soft);
}

.footer-disclaimer {
  margin-top: 0.4rem;
  font-size: 0.78rem;
  color: #9aa1ad;
}

/* ===== Větší obrazovky ===== */

@media (min-width: 640px) {
  .waitlist-form {
    flex-direction: row;
  }

  .waitlist-form input[type="email"] {
    flex: 1;
  }

  .form-success {
    width: auto;
    min-width: 320px;
  }
}

@media (min-width: 820px) {
  .problem-points {
    grid-template-columns: repeat(3, 1fr);
  }

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

  .hero {
    padding-top: 6rem;
  }
}