:root {
  --bg: #0a0a0f;
  --bg-card: #111120;
  --cyan: #00f0ff;
  --magenta: #ff00aa;
  --purple: #7000ff;
  --text: #e0e0f0;
  --text-dim: #707090;
  --border: #1a1a3a;
  --font-mono: "JetBrains Mono", "Fira Code", "Cascadia Code", monospace;
  --font-sans: "Inter", "SF Pro", system-ui, sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  background: var(--bg); color: #e2e8f0; line-height: 1.6;
  min-height: 100vh;
  position: relative;
  background-image: radial-gradient(ellipse at 20% 0%, rgba(15, 118, 110, 0.08) 0%, transparent 50%),
                    radial-gradient(ellipse at 80% 100%, rgba(99, 102, 241, 0.06) 0%, transparent 50%);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background:
    repeating-linear-gradient(
      0deg,
      transparent,
      transparent 2px,
      rgba(0, 240, 255, 0.015) 2px,
      rgba(0, 240, 255, 0.015) 4px
    );
  pointer-events: none;
  z-index: 9999;
}

a {
  color: var(--cyan);
  text-decoration: none;
  transition: color 0.2s, text-shadow 0.2s;
}

a:hover {
  color: var(--magenta);
  text-shadow: 0 0 8px var(--magenta);
}

::selection {
  background: var(--magenta);
  color: var(--bg);
}

/* ─── Nav ─── */

nav {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 10, 15, 0.85);
}

nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--cyan);
  text-shadow: 0 0 12px var(--cyan);
  letter-spacing: 2px;
}

.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}

.nav-links a {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-dim);
  position: relative;
}

.nav-links a::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--cyan);
  box-shadow: 0 0 8px var(--cyan);
  transition: width 0.3s;
}

.nav-links a:hover::after {
  width: 100%;
}

.nav-links a:hover {
  color: var(--cyan);
  text-shadow: none;
}

/* ─── Main ─── */

main .container {
  padding: 48px 1.5rem 80px;
}

/* ─── Footer ─── */

footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  text-align: center;
  color: var(--text-dim);
  font-family: var(--font-mono);
  font-size: 0.8rem;
}

footer a {
  color: var(--cyan);
}

footer a:hover {
  color: var(--cyan);
  text-shadow: 0 0 8px var(--cyan);
}

.social-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-bottom: 1rem;
}

.social-links a {
  font-size: 1.25rem;
  color: var(--text-dim);
  transition: color 0.2s, text-shadow 0.2s;
  display: inline-flex;
  align-items: center;
}

.social-links a:hover {
  color: var(--cyan);
  text-shadow: 0 0 8px var(--cyan);
}

.social-links .icon {
  display: block;
}

.container {
  max-width: 960px; margin: 0 auto; padding: 0 1.5rem;
}

.page-header {
  margin-bottom: 40px;
  padding-top: 48px;
}

.page-header h1 {
  font-size: 32px; font-weight: 600; color: #f1f5f9;
  margin-bottom: 12px; line-height: 1.2;
}

.page-header p {
  color: var(--text-dim); font-size: 15px;
}
.source-note {
  margin-top: 16px; font-size: 11px; color: #475569;
  padding: 8px 12px; background: rgba(255,255,255,0.03);
  border: 1px solid #1e2030; border-radius: 6px;
  display: inline-block;
}

.card {
  background: linear-gradient(135deg, #13151a 0%, #16181f 100%);
  border: 1px solid #1e2030;
  border-radius: 16px; padding: 36px;
  margin-bottom: 24px;
  box-shadow: 0 4px 24px rgba(0,0,0,0.3);
}

.card-label {
  font-size: 11px; font-weight: 600; color: #64748b; letter-spacing: 1px;
  text-transform: uppercase; margin-bottom: 24px;
}

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

.form-group { margin-bottom: 4px; }

.form-group.full { grid-column: 1 / -1; }

.form-group label {
  display: block; font-size: 12px; font-weight: 500; color: #94a3b8;
  margin-bottom: 6px; letter-spacing: 0.2px;
}

.form-group select, .form-group input {
  width: 100%; padding: 11px 14px;
  background: #0a0b0e; border: 1px solid #1e2030; border-radius: 10px;
  color: #f1f5f9; font-size: 15px; font-family: inherit;
  transition: all 0.2s;
  -webkit-appearance: none; appearance: none;
  cursor: pointer;
}

.form-group select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 12px center; padding-right: 36px;
}

.form-group select:focus, .form-group input:focus {
  outline: none; border-color: #0d9488; box-shadow: 0 0 0 3px rgba(13, 148, 136, 0.15);
}

.form-group input::placeholder { color: #475569; }

.btn-primary {
  width: 100%; padding: 14px; border: none; border-radius: 10px;
  background: linear-gradient(135deg, #0d9488, #0891b2);
  color: #fff; font-size: 15px; font-weight: 600; font-family: inherit;
  cursor: pointer; transition: all 0.2s; letter-spacing: 0.2px;
  margin-top: 8px;
}

.btn-primary:hover { transform: translateY(-1px); box-shadow: 0 4px 20px rgba(13, 148, 136, 0.3); }
.btn-primary:active { transform: translateY(0); }
.btn-primary:disabled { opacity: 0.35; cursor: not-allowed; transform: none; box-shadow: none; }

.loading {
  margin-top: 16px; text-align: center; color: #64748b; font-size: 13px; display: none;
}
.loading.show { display: block; }
.loading::after {
  content: ''; display: inline-block; width: 14px; height: 14px;
  border: 2px solid #1e2030; border-top-color: #0d9488; border-radius: 50%;
  animation: spin 0.6s linear infinite; margin-left: 8px; vertical-align: middle;
}
@keyframes spin { to { transform: rotate(360deg); } }

.error {
  display: none; margin-top: 16px; padding: 14px 16px;
  background: rgba(239, 68, 68, 0.1); border: 1px solid rgba(239, 68, 68, 0.25);
  border-radius: 10px; color: #fca5a5; font-size: 14px;
}
.error.show { display: block; }

.result { display: none; }
.result.show { display: block; }

.result-card {
  background: linear-gradient(135deg, #0f172a, #0d1117);
  border: 1px solid rgba(13, 148, 136, 0.2);
  border-radius: 16px; padding: 32px;
  position: relative; overflow: hidden;
}

.result-card::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: linear-gradient(90deg, #0d9488, #0891b2, #6366f1);
}

.result-amount {
  font-size: 40px; font-weight: 700; color: #2dd4bf;
  line-height: 1.1; margin-bottom: 8px;
}

.result-desc {
  font-size: 14px; color: #94a3b8; margin-bottom: 6px;
}

.result-detail {
  font-size: 13px; color: #64748b;
}

.result-detail span { color: #cbd5e1; font-weight: 500; }

.result-badge {
  display: inline-block; margin-top: 16px;
  padding: 6px 14px; background: rgba(13, 148, 136, 0.1);
  border: 1px solid rgba(13, 148, 136, 0.2); border-radius: 20px;
  color: #2dd4bf; font-size: 13px; font-weight: 500;
}

.chart-card { display: none; }
.chart-card.show { display: block; }

.chart-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 24px; flex-wrap: wrap; gap: 12px;
}

.chart-header h2 {
  font-size: 16px; font-weight: 600; color: #f1f5f9;
}

.chart-tabs { display: flex; gap: 4px; }

.chart-tab {
  padding: 7px 16px; border: 1px solid #1e2030; border-radius: 8px;
  background: transparent; color: #64748b; font-size: 13px; font-weight: 500;
  font-family: inherit; cursor: pointer; transition: all 0.2s;
}
.chart-tab:hover { border-color: #0d9488; color: #cbd5e1; }
.chart-tab.active { background: rgba(13, 148, 136, 0.15); border-color: #0d9488; color: #2dd4bf; }

.chart-sub {
  color: #64748b; font-size: 13px; margin-bottom: 20px;
}

.chart-wrap {
  position: relative; width: 100%;
  background: rgba(0,0,0,0.2); border-radius: 12px; padding: 8px;
}

@media (max-width: 768px) {
  main .container { padding: 28px 1rem 60px; }

  .page-header h1 { font-size: 24px; }
  .page-header { margin-bottom: 28px; padding-top: 28px; }

  .card { padding: 24px; border-radius: 12px; }

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

  .result-card { padding: 24px; }
  .result-amount { font-size: 28px; }

  .chart-header { flex-direction: column; align-items: flex-start; }
  .chart-tabs { overflow-x: auto; -webkit-overflow-scrolling: touch; padding-bottom: 4px; }
  .chart-tab { white-space: nowrap; }

  .nav-links { gap: 1rem; }
  .nav-links a { font-size: 0.75rem; }
  footer .social-links { gap: 1rem; flex-wrap: wrap; }
}

@media (max-width: 480px) {
  main .container { padding: 20px 0.75rem 48px; }

  .page-header h1 { font-size: 20px; }
  .page-header p { font-size: 14px; }

  .card { padding: 20px; border-radius: 10px; }

  .form-group select, .form-group input { font-size: 16px; padding: 12px 14px; }

  .result-card { padding: 20px; }
  .result-amount { font-size: 24px; }

  .chart-header h2 { font-size: 14px; }
  .chart-tab { font-size: 12px; padding: 6px 12px; }

  nav .container { flex-direction: column; gap: 0.75rem; }
  .nav-links { gap: 1.5rem; }
  .nav-links a { font-size: 0.7rem; }
}