* {
  box-sizing: border-box;
}

:root {
  --bg: #f3f6fb;
  --surface: #ffffff;
  --surface-soft: #f8faff;
  --text: #0f172a;
  --muted: #475569;
  --border: #dbe3f1;
  --brand: #4f46e5;
  --brand-2: #2563eb;
  --ok: #16a34a;
  --error: #dc2626;
  --shadow: 0 10px 35px rgba(15, 23, 42, 0.08);
  --shadow-soft: 0 3px 14px rgba(15, 23, 42, 0.05);
}

body {
  margin: 0;
  font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: linear-gradient(180deg, #eef3ff 0%, var(--bg) 240px, var(--bg) 100%);
  color: var(--text);
}

.container {
  max-width: 1040px;
  margin: 0 auto 48px;
  padding: 22px 20px 0;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand {
  font-weight: 800;
  font-size: 1.1rem;
  letter-spacing: 0.02em;
  color: #1e1b4b;
}

.language-select {
  border: 1px solid #cbd5e1;
  border-radius: 999px;
  background: #ffffff;
  color: #0f172a;
  padding: 6px 10px;
  font-size: 0.86rem;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.topbar-chip {
  font-size: 0.78rem;
  color: #312e81;
  background: #e0e7ff;
  border: 1px solid #c7d2fe;
  border-radius: 999px;
  padding: 6px 10px;
}

.hero {
  margin-bottom: 16px;
  background: linear-gradient(135deg, #ffffff, #f6f8ff);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 26px;
  box-shadow: var(--shadow);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.45fr 1fr;
  gap: 20px;
}

.hero-aside {
  border: 1px solid #dbe3f1;
  background: #fbfcff;
  border-radius: 14px;
  padding: 14px;
  box-shadow: var(--shadow-soft);
}

.hero-aside h3 {
  margin: 0 0 8px;
  font-size: 0.95rem;
}

.hero-aside ol {
  margin: 0;
  padding-left: 18px;
  color: #334155;
}

.hero-aside li {
  margin-bottom: 4px;
}

.hero-aside p {
  margin: 10px 0 0;
  color: #475569;
  font-size: 0.84rem;
  line-height: 1.45;
}

.badge {
  display: inline-block;
  font-size: 0.76rem;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  color: #312e81;
  background: #eef2ff;
  border: 1px solid #c7d2fe;
  border-radius: 999px;
  padding: 7px 11px;
  margin: 0 0 10px 0;
}

h1 {
  font-size: clamp(1.85rem, 3.4vw, 2.6rem);
  margin: 0 0 10px;
  line-height: 1.15;
  color: #0b132d;
}

.subtitle {
  color: var(--muted);
  margin: 0 0 14px;
  max-width: 72ch;
  line-height: 1.5;
}

.hero-highlights {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.hero-highlights span {
  font-size: 0.82rem;
  border: 1px solid #dbeafe;
  background: #f8fbff;
  color: #1e3a8a;
  padding: 6px 10px;
  border-radius: 999px;
}

.card,
.help,
.viz,
.workflow,
.features {
  border: 1px solid #dbe3f1;
  border-radius: 16px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.card,
.help,
.viz,
.workflow {
  padding: 18px;
}

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 10px;
}

.section-head h2 {
  margin: 0;
  font-size: 1.05rem;
}

.section-subtle {
  color: #64748b;
  font-size: 0.78rem;
  white-space: nowrap;
}

.dropzone {
  border: 2px dashed #93c5fd;
  border-radius: 12px;
  padding: 36px 20px;
  text-align: center;
  background: linear-gradient(180deg, #f9fbff, #f4f8ff);
  cursor: pointer;
  transition: border-color 0.18s ease, background 0.18s ease;
  margin-bottom: 14px;
  color: #1e293b;
}

.dropzone:hover,
.dropzone:focus {
  border-color: #4f46e5;
  background: #eef2ff;
}

.dropzone.drag-over {
  border-color: #16a34a;
  background: #ecfdf3;
}

.file-name {
  margin: 10px 0 0;
  color: #334155;
  font-size: 0.95rem;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 12px;
}

.field label {
  display: block;
  margin-bottom: 6px;
  color: #334155;
  font-size: 0.92rem;
  font-weight: 600;
}

.control {
  width: 100%;
  background: #ffffff;
  color: var(--text);
  border: 1px solid #cbd5e1;
  border-radius: 10px;
  padding: 10px 12px;
  transition: border-color 0.14s ease, box-shadow 0.14s ease;
}

.control:focus {
  outline: none;
  border-color: #818cf8;
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.checkbox-row {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  margin-top: 14px;
  color: #334155;
}

.primary-btn {
  margin-top: 14px;
  border: none;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  color: #ffffff;
  font-weight: 700;
  padding: 12px 18px;
  cursor: pointer;
  box-shadow: 0 8px 20px rgba(37, 99, 235, 0.28);
  transition: transform 0.12s ease, box-shadow 0.12s ease, filter 0.12s ease;
}

.primary-btn:hover {
  transform: translateY(-1px);
  filter: saturate(1.05);
}

.primary-btn:disabled {
  opacity: 0.75;
  cursor: not-allowed;
  transform: none;
}

.status {
  margin-top: 12px;
  min-height: 22px;
  color: #334155;
}

.status.error {
  color: var(--error);
}

.status.success {
  color: var(--ok);
}

.help {
  margin-top: 14px;
}

.help h2 {
  font-size: 1.05rem;
  margin: 0 0 8px;
}

.help p {
  margin: 0;
  color: #334155;
  line-height: 1.45;
}

.viz {
  margin-top: 14px;
}

.viz h2 {
  font-size: 1rem;
  margin: 0 0 6px;
}

.viz-subtitle {
  margin: 0 0 10px;
  color: #475569;
}

.viz-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-bottom: 10px;
}

.stat-card {
  border: 1px solid #dbe3f1;
  border-radius: 10px;
  padding: 10px;
  background: var(--surface-soft);
}

.stat-label {
  display: block;
  font-size: 0.82rem;
  color: #64748b;
}

.stat-value {
  display: block;
  font-size: 1.25rem;
  font-weight: 700;
}

.viz-pairs {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(170px, 1fr));
  gap: 10px;
}

.pair-card {
  border: 1px solid #dbe3f1;
  border-radius: 10px;
  padding: 10px;
  background: var(--surface-soft);
}

.pair-title {
  display: block;
  font-size: 0.82rem;
  color: #475569;
  margin-bottom: 6px;
}

.sheet-preview {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 1px 1fr;
  gap: 0;
  border: 1px solid #cbd5e1;
  border-radius: 10px;
  overflow: hidden;
  background: linear-gradient(180deg, #ffffff, #f8fbff);
  min-height: 94px;
}

.sheet-half {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 10px 8px;
}

.sheet-divider {
  width: 1px;
  background: repeating-linear-gradient(
    to bottom,
    rgba(99, 102, 241, 0.9),
    rgba(99, 102, 241, 0.9) 4px,
    rgba(99, 102, 241, 0.2) 4px,
    rgba(99, 102, 241, 0.2) 8px
  );
}

.sheet-half-label {
  display: block;
  font-size: 0.72rem;
  color: #64748b;
  letter-spacing: 0.02em;
}

.sheet-half-value {
  display: block;
  margin-top: 3px;
  font-size: 1.2rem;
  font-weight: 700;
}

.workflow {
  margin-top: 14px;
}

.workflow h2 {
  font-size: 1rem;
  margin: 0 0 6px;
}

.workflow-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.workflow-card {
  border: 1px solid #dbe3f1;
  border-radius: 14px;
  padding: 12px;
  background: var(--surface-soft);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.8);
}

.workflow-head {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
}

.workflow-card h3 {
  margin: 0;
  font-size: 0.92rem;
  color: #1e293b;
}

.workflow-pill {
  display: inline-flex;
  align-items: center;
  padding: 3px 8px;
  border-radius: 999px;
  font-size: 0.72rem;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  color: #3730a3;
  background: #eef2ff;
  border: 1px solid #c7d2fe;
  white-space: nowrap;
}

.workflow-svg {
  width: 100%;
  height: auto;
  border: 1px solid #dbe3f1;
  border-radius: 12px;
  background:
    radial-gradient(circle at 10% 12%, rgba(79, 70, 229, 0.12), transparent 40%),
    linear-gradient(180deg, #ffffff, #f4f7ff);
}

.workflow-note {
  margin: 8px 0 0;
  color: #475569;
  font-size: 0.88rem;
  line-height: 1.35;
}

.wf-block {
  fill: rgba(99, 102, 241, 0.18);
  stroke: rgba(79, 70, 229, 0.9);
  stroke-width: 1.2;
}

.wf-block-2 {
  fill: rgba(99, 102, 241, 0.12);
}

.wf-block-3 {
  fill: rgba(99, 102, 241, 0.08);
}

.wf-sheet {
  fill: rgba(148, 163, 184, 0.24);
  stroke: rgba(71, 85, 105, 0.82);
  stroke-width: 1.2;
}

.wf-sheet-folded {
  fill: rgba(34, 197, 94, 0.2);
  stroke: rgba(22, 163, 74, 0.88);
}

.wf-fold {
  stroke: rgba(71, 85, 105, 0.8);
  stroke-width: 1.2;
  stroke-dasharray: 3 3;
}

.wf-fold-curve {
  fill: none;
  stroke: rgba(71, 85, 105, 0.75);
  stroke-width: 1.6;
}

.wf-arrow {
  fill: none;
  stroke: rgba(79, 70, 229, 0.92);
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.wf-text {
  fill: #334155;
  font-size: 9px;
}

.wf-page {
  fill: #0f172a;
  font-size: 12px;
  font-weight: 700;
}

.wf-step-dot {
  fill: rgba(79, 70, 229, 0.9);
  stroke: rgba(255, 255, 255, 0.95);
  stroke-width: 1.2;
}

.wf-step-dot-green {
  fill: rgba(22, 163, 74, 0.9);
}

.wf-step-num {
  fill: #ffffff;
  font-size: 10px;
  font-weight: 800;
}

.features {
  margin-top: 14px;
  padding: 14px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}

.feature {
  border: 1px solid #dbe3f1;
  border-radius: 12px;
  padding: 12px;
  background: var(--surface-soft);
  box-shadow: var(--shadow-soft);
}

.feature h3 {
  margin: 0 0 6px;
  font-size: 0.95rem;
}

.feature p {
  margin: 0;
  color: #475569;
  font-size: 0.86rem;
  line-height: 1.45;
}

@media (max-width: 760px) {
  .grid-2 {
    grid-template-columns: 1fr;
  }
  .viz-stats {
    grid-template-columns: 1fr;
  }
  .workflow-grid {
    grid-template-columns: 1fr;
  }
  .features {
    grid-template-columns: 1fr;
  }
  .topbar {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }
  .topbar-actions {
    width: 100%;
    justify-content: space-between;
  }
  .hero-grid {
    grid-template-columns: 1fr;
  }
  .section-head {
    align-items: flex-start;
    flex-direction: column;
    gap: 4px;
  }
  .section-subtle {
    white-space: normal;
  }
}