/* ===== Reset & Base ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg:           #ffffff;
  --bg-alt:       #f8fafc;
  --text:         #0f172a;
  --text-muted:   #64748b;
  --accent:       #6366f1;
  --accent-dark:  #4f46e5;
  --accent-light: #eef2ff;
  --border:       #e2e8f0;
  --shadow-sm:    0 1px 2px rgba(0,0,0,.05), 0 1px 8px rgba(0,0,0,.04);
  --shadow-md:    0 4px 16px rgba(0,0,0,.08), 0 1px 4px rgba(0,0,0,.04);
  --shadow-lg:    0 20px 60px rgba(0,0,0,.12), 0 4px 20px rgba(0,0,0,.07);
  --radius-sm:    8px;
  --radius-md:    12px;
  --radius-lg:    20px;
  --font-sans:    'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono:    'JetBrains Mono', 'Fira Code', Consolas, monospace;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* ===== Layout ===== */
.container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 96px 0;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 22px;
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: 2px solid transparent;
  transition: background 0.15s, border-color 0.15s, color 0.15s, transform 0.1s, box-shadow 0.15s;
  white-space: nowrap;
  line-height: 1;
}

.btn:active {
  transform: translateY(1px);
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.875rem;
}

.btn-full {
  width: 100%;
  padding: 13px 22px;
  font-size: 1rem;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
  box-shadow: 0 1px 4px rgba(99,102,241,.25);
}

.btn-primary:hover {
  background: var(--accent-dark);
  border-color: var(--accent-dark);
  box-shadow: 0 4px 14px rgba(99,102,241,.35);
}

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

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

/* ===== Nav ===== */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.nav-logo img {
  border-radius: 8px;
}

/* ===== Hero ===== */
.hero {
  padding: 80px 0 72px;
  background: linear-gradient(160deg, #f8faff 0%, #f0f4fe 100%);
  overflow: hidden;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1.55fr;
  gap: 64px;
  align-items: center;
}

.badge {
  display: inline-flex;
  align-items: center;
  background: var(--accent-light);
  color: var(--accent);
  padding: 5px 14px;
  border-radius: 999px;
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.025em;
  margin-bottom: 24px;
}

.hero-text h1 {
  font-size: clamp(2.75rem, 5vw, 3.75rem);
  font-weight: 800;
  line-height: 1.08;
  letter-spacing: -0.03em;
  color: var(--text);
  margin-bottom: 20px;
}

.lead {
  font-size: 1.1rem;
  color: var(--text-muted);
  line-height: 1.75;
  max-width: 460px;
  margin-bottom: 36px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 20px;
}

.version-tag {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  letter-spacing: 0.01em;
}

.version-tag.centered {
  text-align: center;
  margin-top: 24px;
}

.hero-visual {
  position: relative;
}

.hero-visual::before {
  content: '';
  position: absolute;
  inset: -32px;
  background: radial-gradient(ellipse at 55% 45%, rgba(99,102,241,.12) 0%, transparent 68%);
  z-index: 0;
  pointer-events: none;
}

.screenshot {
  position: relative;
  z-index: 1;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  border: 1px solid rgba(0,0,0,.07);
  width: 100%;
}

/* ===== Section headings ===== */
.section-heading {
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  text-align: center;
  margin-bottom: 12px;
}

.section-sub {
  font-size: 1.05rem;
  color: var(--text-muted);
  text-align: center;
  max-width: 500px;
  margin: 0 auto 56px;
  line-height: 1.65;
}

/* ===== Features ===== */
.features-section {
  background: var(--bg-alt);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}

.feature-card {
  background: var(--bg);
  border-radius: var(--radius-md);
  padding: 28px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}

.feature-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.feature-icon {
  width: 46px;
  height: 46px;
  background: var(--accent-light);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  margin-bottom: 16px;
  flex-shrink: 0;
}

.feature-card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.7;
}

/* ===== Download ===== */
.download-section {
  background: var(--bg);
}

.platform-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}

.platform-card {
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 36px 28px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  background: var(--bg);
  box-shadow: var(--shadow-sm);
  text-align: center;
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}

.platform-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.platform-icon {
  color: var(--text-muted);
  margin-bottom: 8px;
}

.platform-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.format-tag {
  font-family: var(--font-mono);
  font-size: 0.775rem;
  color: var(--text-muted);
  background: var(--bg-alt);
  border: 1px solid var(--border);
  padding: 3px 9px;
  border-radius: 5px;
  margin-bottom: 16px;
}

.platform-card .btn {
  width: 100%;
}

/* ===== Feedback ===== */
.feedback-section {
  background: var(--bg-alt);
}

.feedback-inner {
  max-width: 620px;
  margin: 0 auto;
}

.feedback-form {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 36px;
  box-shadow: var(--shadow-sm);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 20px;
}

.form-group label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  color: var(--text);
  background: var(--bg);
  transition: border-color 0.15s, box-shadow 0.15s;
  outline: none;
  -webkit-appearance: none;
  appearance: none;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: #94a3b8;
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(99,102,241,.12);
}

.form-group textarea {
  resize: vertical;
  min-height: 130px;
  line-height: 1.6;
}

.feedback-success {
  background: var(--bg);
  border: 1.5px solid #86efac;
  border-radius: var(--radius-md);
  padding: 48px 36px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  color: #16a34a;
}

.feedback-success p {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
}

/* ===== Footer ===== */
.footer {
  padding: 28px 0;
  border-top: 1px solid var(--border);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text);
  text-decoration: none;
}

.footer-logo img {
  border-radius: 6px;
}

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

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .hero-inner {
    grid-template-columns: 1fr;
    gap: 48px;
  }

  .hero-visual {
    order: -1;
  }

  .lead {
    max-width: 100%;
  }
}

@media (max-width: 640px) {
  .section {
    padding: 64px 0;
  }

  .hero {
    padding: 52px 0 48px;
  }

  .hero-actions {
    flex-direction: column;
  }

  .hero-actions .btn {
    width: 100%;
  }

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

  .feedback-form {
    padding: 24px 20px;
  }

  .platform-card {
    padding: 28px 20px;
  }

  .footer-inner {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }
}