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

:root {
  --black: #0a0a0a;
  --white: #f8f7f4;
  --mid: #6b6b6b;
  --light: #d4d2cd;
  --accent: #1a1a1a;
  --border: rgba(10, 10, 10, 0.12);
  --radius: 2px;
}

html {
  font-size: 16px;
}

body {
  background: var(--white);
  color: var(--black);
  font-family: "DM Sans", sans-serif;
  font-weight: 300;
  min-height: 100vh;
  overflow-x: hidden;
}

/* HEADER */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 2rem 3rem;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: var(--white);
  z-index: 100;
}

.logo {
  font-family: "Playfair Display", serif;
  font-size: 1.3rem;
  letter-spacing: -0.02em;
}

.logo span {
  font-style: italic;
  color: var(--mid);
}

nav {
  display: flex;
  gap: 2.5rem;
}

nav a {
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--mid);
  transition: color 0.2s;
}

nav a:hover {
  color: var(--black);
}

.desktop-nav {
  display: flex;
  gap: 2.5rem;
}

/* Mobile Menu Button */
.menu-btn {
  display: none;
  flex-direction: column;
  gap: 0.4rem;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  z-index: 101;
}

.menu-btn span {
  width: 1.2rem;
  height: 2px;
  background: var(--black);
  transition: all 0.3s ease;
}

/* Mobile Menu */
#mobile-menu {
  display: none;
  position: fixed;
  top: 60px;
  left: 0;
  right: 0;
  background: var(--white);
  flex-direction: column;
  gap: 0;
  padding: 1rem 0;
  border-bottom: 1px solid var(--border);
  z-index: 100;
  max-height: calc(100vh - 60px);
  overflow-y: auto;
}

#mobile-menu.active {
  display: flex;
}

#mobile-menu a {
  padding: 1rem 1.5rem;
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--mid);
  transition:
    color 0.2s,
    background 0.2s;
  border-bottom: 1px solid var(--border);
}

#mobile-menu a:hover,
#mobile-menu a:active {
  background: var(--accent);
  color: var(--black);
}

/* HERO */
.hero {
  padding: 5rem 3rem 3rem;
  max-width: 1200px;
  margin: 0 auto;
}

.hero-label {
  font-family: "DM Mono", monospace;
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--mid);
  margin-bottom: 1rem;
}

.hero h1 {
  font-family: "Playfair Display", serif;
  font-size: clamp(2.8rem, 6vw, 5.5rem);
  line-height: 1.05;
  letter-spacing: -0.03em;
  font-weight: 700;
  max-width: 700px;
}

.hero h1 em {
  font-style: italic;
  color: var(--mid);
}

/* MAIN LAYOUT */
.calculator-wrap {
  max-width: 1200px;
  margin: 0 auto;
  padding: 3rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: start;
}

/* INPUTS PANEL */
.inputs-panel {
  animation: fadeUp 0.6s ease both;
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.section-label {
  font-family: "DM Mono", monospace;
  font-size: 0.65rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--mid);
  margin-bottom: 2rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.section-label::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--border);
}

.field {
  margin-bottom: 2rem;
}

.field label {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 0.8rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--mid);
  margin-bottom: 0.75rem;
}

.field label .value-display {
  font-family: "DM Mono", monospace;
  font-size: 1rem;
  color: var(--black);
  letter-spacing: -0.02em;
  text-transform: none;
}

/* Custom range slider */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 1px;
  background: var(--light);
  outline: none;
  cursor: pointer;
  position: relative;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--black);
  cursor: pointer;
  transition:
    transform 0.15s,
    box-shadow 0.15s;
  box-shadow: 0 0 0 0 rgba(10, 10, 10, 0.15);
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.2);
  box-shadow: 0 0 0 8px rgba(10, 10, 10, 0.08);
}

input[type="range"]::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--black);
  cursor: pointer;
  border: none;
}

.range-track {
  position: relative;
  margin-bottom: 0.5rem;
}

.range-fill {
  position: absolute;
  top: 50%;
  left: 0;
  height: 1px;
  background: var(--black);
  transform: translateY(-50%);
  pointer-events: none;
}

/* Number Input */
.number-input-wrap {
  position: relative;
  display: flex;
  align-items: center;
  border-bottom: 1px solid var(--black);
  transition: border-color 0.2s;
}

.number-input-wrap:focus-within {
  border-color: var(--black);
}

.currency-prefix {
  font-family: "DM Mono", monospace;
  font-size: 1.1rem;
  color: var(--mid);
  padding-right: 0.25rem;
}

input[type="number"],
input[type="text"].styled {
  -webkit-appearance: none;
  appearance: none;
  border: none;
  background: transparent;
  font-family: "DM Mono", monospace;
  font-size: 1.4rem;
  color: var(--black);
  width: 100%;
  padding: 0.5rem 0;
  outline: none;
  letter-spacing: -0.02em;
}

input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
}

/* TOGGLE TABS */
.tab-group {
  display: flex;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 2.5rem;
}

.tab-btn {
  flex: 1;
  padding: 0.65rem;
  background: transparent;
  border: none;
  font-family: "DM Mono", monospace;
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  cursor: pointer;
  color: var(--mid);
  transition: all 0.2s;
}

.tab-btn.active {
  background: var(--black);
  color: var(--white);
}

/* RESULTS PANEL */
.results-panel {
  animation: fadeUp 0.6s 0.15s ease both;
}

.result-hero {
  margin-bottom: 3rem;
}

.result-hero .result-label {
  font-family: "DM Mono", monospace;
  font-size: 0.65rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--mid);
  margin-bottom: 0.75rem;
}

.result-hero .monthly-payment {
  font-family: "Playfair Display", serif;
  font-size: clamp(3rem, 5vw, 4.5rem);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1;
  display: flex;
  align-items: baseline;
  gap: 0.2rem;
}

.monthly-payment .currency {
  font-size: 0.45em;
  color: var(--mid);
  font-style: italic;
}

.monthly-payment .per-month {
  font-size: 0.22em;
  color: var(--mid);
  font-family: "DM Mono", monospace;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  font-style: normal;
  align-self: flex-end;
  padding-bottom: 0.3em;
}

/* BREAKDOWN */
.breakdown {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  margin-bottom: 2.5rem;
}

.breakdown-item {
  background: var(--white);
  padding: 1.25rem;
}

.breakdown-item .b-label {
  font-family: "DM Mono", monospace;
  font-size: 0.6rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--mid);
  margin-bottom: 0.4rem;
}

.breakdown-item .b-value {
  font-family: "DM Mono", monospace;
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--black);
  letter-spacing: -0.02em;
}

/* PIE / BAR CHART */
.chart-section {
  margin-bottom: 2.5rem;
}

.chart-bars {
  display: flex;
  height: 8px;
  border-radius: 1px;
  overflow: hidden;
  gap: 1px;
  margin-bottom: 1rem;
}

.bar-principal {
  background: var(--black);
  transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.bar-interest {
  background: var(--light);
  transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  flex: 1;
}

.chart-legend {
  display: flex;
  gap: 2rem;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.72rem;
  font-family: "DM Mono", monospace;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--mid);
}

.legend-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
}

/* AMORTIZATION */
.amort-title {
  font-family: "DM Mono", monospace;
  font-size: 0.65rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--mid);
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.amort-title::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--border);
}

.amort-table {
  width: 100%;
  border-collapse: collapse;
  font-family: "DM Mono", monospace;
  font-size: 0.72rem;
}

.amort-table th {
  text-align: left;
  padding: 0.5rem 0.75rem;
  font-weight: 400;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--mid);
  border-bottom: 1px solid var(--border);
  font-size: 0.6rem;
}

.amort-table td {
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--border);
  color: var(--black);
  font-size: 0.7rem;
}

.amort-table tr:last-child td {
  border-bottom: none;
}

.amort-table tr:hover td {
  background: rgba(10, 10, 10, 0.03);
}

.show-more-btn {
  width: 100%;
  padding: 0.9rem;
  background: transparent;
  border: 1px solid var(--border);
  font-family: "DM Mono", monospace;
  font-size: 0.7rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  cursor: pointer;
  color: var(--mid);
  margin-top: 0.5rem;
  transition: all 0.2s;
}

.show-more-btn:hover {
  background: var(--black);
  color: var(--white);
  border-color: var(--black);
}

/* FOOTER */
footer {
  border-top: 1px solid var(--border);
  padding: 2rem 3rem;
  max-width: 1200px;
  margin: 3rem auto 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

footer p {
  font-size: 0.7rem;
  color: var(--mid);
  font-family: "DM Mono", monospace;
  letter-spacing: 0.05em;
}

/* AD PLACEHOLDER */
.ad-strip {
  background: #f0efe9;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 1rem 3rem;
  text-align: center;
  font-family: "DM Mono", monospace;
  font-size: 0.6rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--light);
}

@media (max-width: 768px) {
  .calculator-wrap {
    grid-template-columns: 1fr;
    gap: 3rem;
  }

  header {
    padding: 1.5rem;
  }

  .menu-btn {
    display: flex;
  }

  .desktop-nav {
    display: none;
  }

  .hero {
    padding: 3rem 1.5rem 2rem;
  }

  .calculator-wrap {
    padding: 1.5rem;
  }

  footer {
    flex-direction: column;
    gap: 1rem;
    padding: 1.5rem;
  }
}