:root {
  --accent: #0f766e;
  --accent-light: #ccfbf1;
  --accent-dark: #0d5f58;
  --bg: #ffffff;
  --bg-alt: #f9fafb;
  --border: #e5e7eb;
  --text: #1f2937;
  --text-muted: #6b7280;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.1);
  --shadow-lg: 0 4px 12px rgba(0,0,0,0.1);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Nav */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--accent);
  box-shadow: var(--shadow-lg);
}

.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 16px;
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: 56px;
  flex-wrap: wrap;
}

.logo {
  color: #fff;
  font-weight: 700;
  font-size: 1.15rem;
  text-decoration: none;
  margin-right: auto;
  white-space: nowrap;
}

.nav-links {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}

.nav-links a {
  color: rgba(255,255,255,0.85);
  text-decoration: none;
  font-size: 0.85rem;
  padding: 6px 10px;
  border-radius: var(--radius);
  transition: background 0.15s, color 0.15s;
  white-space: nowrap;
}

.nav-links a:hover,
.nav-links a.active {
  background: rgba(255,255,255,0.18);
  color: #fff;
}

/* Layout */
.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 24px 16px 48px;
  flex: 1;
  width: 100%;
}

h1 {
  font-size: 1.75rem;
  color: var(--accent);
  margin-bottom: 8px;
}

.intro {
  color: var(--text-muted);
  margin-bottom: 24px;
  max-width: 720px;
  line-height: 1.7;
}

/* AdSense placeholder */
.adslot {
  min-height: 90px;
  background: #f3f4f6;
  text-align: center;
  padding: 10px;
  margin: 16px 0;
  border-radius: 6px;
  color: #999;
  font-size: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Forms */
.calc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 24px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

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

label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text);
}

input[type="number"],
input[type="text"],
input[type="date"],
select {
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.95rem;
  color: var(--text);
  background: var(--bg);
  transition: border-color 0.15s, box-shadow 0.15s;
  width: 100%;
}

input:focus, select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(15,118,110,0.12);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 32px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
  margin-bottom: 24px;
}

.btn:hover { background: var(--accent-dark); }

/* Results */
.results {
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}

.results h2 {
  font-size: 1.15rem;
  color: var(--accent);
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--accent-light);
}

.result-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
}

.result-row:last-child { border-bottom: none; }

.result-label {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.result-value {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text);
}

.result-value.highlight {
  color: var(--accent);
  font-size: 1.2rem;
}

.result-value.negative { color: #dc2626; }
.result-value.positive { color: var(--accent); }

/* Footer */
footer {
  text-align: center;
  padding: 24px 16px;
  font-size: 0.8rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
  background: var(--bg-alt);
}

/* Responsive */
@media (max-width: 640px) {
  .calc-grid { grid-template-columns: 1fr; }
  h1 { font-size: 1.4rem; }
  .nav-inner { padding: 8px 12px; }
  .nav-links a { font-size: 0.78rem; padding: 5px 7px; }
  .logo { font-size: 1rem; }
  .results { padding: 16px; }
}