:root {
  --bg: #07111c;
  --bg-soft: #0d1b2a;
  --panel: rgba(12, 21, 32, 0.92);
  --panel-strong: #101d2b;
  --panel-alt: #0b1725;
  --border: rgba(148, 163, 184, 0.18);
  --text: #edf6ff;
  --muted: #9bb0c4;
  --primary: #3dd9c6;
  --primary-strong: #27c6af;
  --primary-soft: rgba(61, 217, 198, 0.12);
  --accent: #5ea3ff;
  --accent-soft: rgba(94, 163, 255, 0.14);
  --highlight: #f5fbff;
  --shadow: 0 24px 70px rgba(2, 6, 17, 0.5);
  --success: #7ef7c7;
  --warning: #ffd166;
}

body.light-theme {
  --bg: #f3f7fb;
  --bg-soft: #eef5ff;
  --panel: rgba(255, 255, 255, 0.9);
  --panel-strong: #ffffff;
  --panel-alt: #eef4ff;
  --border: rgba(15, 23, 42, 0.08);
  --text: #0f1e2d;
  --muted: #53657b;
  --primary: #117d6e;
  --primary-strong: #0d685e;
  --primary-soft: rgba(17, 125, 110, 0.12);
  --accent: #2a65d8;
  --accent-soft: rgba(42, 101, 216, 0.1);
  --highlight: #0d1830;
  --shadow: 0 24px 60px rgba(15, 30, 45, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background:
    radial-gradient(circle at top left, rgba(61, 217, 198, 0.12), transparent 22%),
    radial-gradient(circle at bottom right, rgba(94, 163, 255, 0.1), transparent 24%),
    linear-gradient(180deg, var(--bg) 0%, var(--bg-soft) 100%);
  color: var(--text);
  transition: background 0.25s ease, color 0.25s ease;
}

.topbar {
  width: 100%;
  padding: 20px 20px 0;
}

.topbar-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: rgba(10, 18, 29, 0.4);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 12px 16px;
  backdrop-filter: blur(10px);
}

body.light-theme .topbar-inner {
  background: rgba(255, 255, 255, 0.7);
}

.brand-wrap {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-mark {
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: #04141e;
  font-weight: 800;
  font-size: 1.05rem;
}

.brand-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.brand-name {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text);
}

.brand-subtitle {
  font-size: 0.73rem;
  color: var(--muted);
}

.theme-toggle {
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.04);
  color: var(--text);
  border-radius: 999px;
  width: 46px;
  height: 46px;
  display: grid;
  place-items: center;
  cursor: pointer;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.theme-toggle:hover {
  transform: translateY(-1px);
  border-color: rgba(94, 163, 255, 0.4);
}

.toggle-icon {
  font-size: 1.1rem;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px 20px 60px;
}

.hero {
  display: grid;
  grid-template-columns: 1.6fr 0.9fr;
  gap: 22px;
  align-items: stretch;
  margin: 28px 0 24px;
  padding: 6px 0;
}

.hero-copy,
.hero-metrics {
  background: rgba(15, 25, 36, 0.7);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 28px 26px;
  box-shadow: var(--shadow);
}

body.light-theme .hero-copy,
body.light-theme .hero-metrics {
  background: rgba(255, 255, 255, 0.8);
}

.eyebrow,
.section-kicker {
  display: inline-block;
  background: var(--primary-soft);
  color: var(--primary);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 8px 12px;
  border-radius: 999px;
  margin-bottom: 16px;
}

.hero-copy h1 {
  margin: 0;
  font-size: clamp(2.2rem, 4vw, 4rem);
  line-height: 1.06;
  letter-spacing: -0.05em;
  color: var(--highlight);
}

.hero-copy p {
  margin: 18px 0 0;
  max-width: 620px;
  color: var(--muted);
  font-size: 1.04rem;
  line-height: 1.7;
}

.hero-metrics {
  display: grid;
  gap: 14px;
  align-content: center;
}

.metric-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 16px 18px;
}

.metric-label {
  color: var(--muted);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.metric-item strong {
  color: var(--highlight);
  font-size: 1.2rem;
}

.card,
.comparison-section {
  width: 100%;
  background: linear-gradient(180deg, rgba(15, 24, 36, 0.92) 0%, rgba(8, 17, 27, 0.96) 100%);
  border: 1px solid var(--border);
  border-radius: 28px;
  box-shadow: var(--shadow);
}

body.light-theme .card,
body.light-theme .comparison-section {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.9) 0%, rgba(250, 253, 255, 0.96) 100%);
}

.card {
  padding: 32px;
}

.section-heading {
  margin-bottom: 20px;
}

.section-heading h2 {
  margin: 0;
  font-size: clamp(1.5rem, 2vw, 2.2rem);
  letter-spacing: -0.03em;
  color: var(--highlight);
}

.calculator-form {
  display: grid;
  gap: 18px;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 20px;
}

.field-group {
  display: grid;
  gap: 10px;
}

label {
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--text);
}

.field-help {
  margin-top: -4px;
  font-size: 0.75rem;
  line-height: 1.4;
  color: var(--muted);
}

input,
select {
  width: 100%;
  padding: 14px 16px;
  border: 1px solid rgba(148, 163, 184, 0.18);
  border-radius: 14px;
  background: rgba(17, 26, 38, 0.9);
  font-size: 1rem;
  color: var(--text);
  transition: border-color 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
}

body.light-theme input,
body.light-theme select {
  background: rgba(245, 249, 255, 0.9);
  border-color: rgba(15, 23, 42, 0.08);
}

input::placeholder,
select {
  color: var(--muted);
}

input:focus,
select:focus {
  outline: none;
  border-color: rgba(94, 163, 255, 0.8);
  box-shadow: 0 0 0 4px rgba(94, 163, 255, 0.12);
  transform: translateY(-1px);
}

button {
  border: none;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-strong) 100%);
  color: #03171a;
  font-size: 1rem;
  font-weight: 800;
  padding: 16px 22px;
  cursor: pointer;
  box-shadow: 0 14px 28px rgba(39, 198, 175, 0.2);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

button:hover {
  transform: translateY(-1px);
  box-shadow: 0 18px 32px rgba(39, 198, 175, 0.28);
}

button:active {
  transform: translateY(0);
}

.mode-toggle {
  display: inline-flex;
  gap: 8px;
  padding: 6px;
  margin: 12px 0 20px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.02);
}

.mode-tab {
  background: transparent;
  color: var(--muted);
  border: none;
  border-radius: 10px;
  padding: 10px 18px;
  font-size: 0.92rem;
  font-weight: 700;
  cursor: pointer;
  box-shadow: none;
}

.mode-tab.active {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-strong) 100%);
  color: #041a1e;
  box-shadow: 0 10px 20px rgba(39, 198, 175, 0.2);
}

.mode-panel.hidden {
  display: none;
}

.results {
  margin-top: 30px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.result-box {
  background: linear-gradient(180deg, rgba(18, 29, 41, 0.95) 0%, rgba(12, 21, 32, 0.98) 100%);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 18px 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 12px;
  min-height: 110px;
}

body.light-theme .result-box {
  background: linear-gradient(180deg, rgba(250, 252, 255, 0.95) 0%, rgba(243, 247, 251, 0.98) 100%);
}

.result-box.highlight {
  background: linear-gradient(135deg, rgba(61, 217, 198, 0.12) 0%, rgba(94, 163, 255, 0.12) 100%);
  border-color: rgba(61, 217, 198, 0.25);
}

.label {
  font-size: 0.9rem;
  color: var(--muted);
  line-height: 1.4;
}

.result-value {
  font-size: clamp(1.25rem, 2vw, 2rem);
  line-height: 1.2;
  color: var(--highlight);
  letter-spacing: -0.03em;
}

.chart-panel,
.scenario-chart-panel {
  margin-top: 28px;
  background: linear-gradient(180deg, rgba(12, 22, 32, 0.95) 0%, rgba(7, 17, 28, 0.98) 100%);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 18px 18px 10px;
}

body.light-theme .chart-panel,
body.light-theme .scenario-chart-panel {
  background: linear-gradient(180deg, rgba(249, 252, 255, 0.95) 0%, rgba(240, 246, 251, 0.98) 100%);
}

.chart-header {
  margin-bottom: 12px;
}

.chart-header h3 {
  margin: 0;
  font-size: 1.05rem;
  color: var(--text);
  letter-spacing: -0.02em;
}

.chart-wrap {
  height: 330px;
  position: relative;
}

.small-chart-wrap {
  height: 260px;
}

.note {
  margin: 22px 0 0;
  font-size: 0.9rem;
  color: var(--muted);
  line-height: 1.6;
}

.note em {
  font-style: italic;
}

.comparison-section {
  margin-top: 30px;
  padding: 28px 24px 24px;
}

.scenario-grid {
  margin-top: 10px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.scenario-card {
  padding: 18px 18px 16px;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.02);
}

.scenario-card h3 {
  margin: 0 0 10px;
  font-size: 1.2rem;
  color: var(--text);
}

.scenario-card .scenario-value {
  margin: 0;
  font-size: 1.7rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--highlight);
}

.scenario-card .scenario-meta {
  margin-top: 10px;
  color: var(--muted);
  font-size: 0.8rem;
}

@media (max-width: 720px) {
  .hero {
    grid-template-columns: 1fr;
  }

  .card,
  .comparison-section {
    padding: 24px 18px;
    border-radius: 20px;
  }

  .form-grid,
  .results,
  .scenario-grid {
    grid-template-columns: 1fr;
  }

  .result-box {
    min-height: auto;
  }

  .chart-wrap,
  .small-chart-wrap {
    height: 260px;
  }
}

@media (max-width: 480px) {
  .topbar {
    padding: 16px 14px 0;
  }

  .container {
    padding: 18px 14px 48px;
  }

  .field-group {
    gap: 8px;
  }

  input {
    padding: 12px 14px;
  }

  button {
    width: 100%;
  }

  .hero-copy,
  .hero-metrics {
    padding: 20px 16px;
  }
}