:root {
  --bg-color: #0b0f19;
  --app-bg: #111827;
  --text-primary: #f9fafb;
  --text-secondary: #9ca3af;
  --accent-color: #38bdf8;
  --panel-bg: rgba(31, 41, 55, 0.5);
  --border-color: rgba(75, 85, 99, 0.4);

  --gradient-main: linear-gradient(135deg, #3b82f6, #8b5cf6);
  --gradient-success: linear-gradient(135deg, #f59e0b, #ef4444);
  --gradient-beer: linear-gradient(135deg, #d97706, #b45309);
}

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

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--bg-color);
  color: var(--text-primary);
  display: flex;
  justify-content: center;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

.app {
  width: 100%;
  max-width: 680px;
  min-height: 100vh;
  background-color: var(--app-bg);
  padding: 32px 20px;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

@media (min-width: 768px) {
  .app {
    margin: 40px auto;
    min-height: auto;
    border-radius: 32px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  }
}

/* ── Header ── */
.app-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 8px;
}

.logo-icon {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  border: 2px solid var(--accent-color);
  padding: 2px;
}

.header-titles h2 {
  font-size: 14px;
  color: var(--accent-color);
  text-transform: uppercase;
  letter-spacing: 2px;
  font-family: 'Outfit', sans-serif;
}

.header-titles h1 {
  font-size: 24px;
  font-weight: 700;
}

/* ── Card glass ── */
.card-glass {
  background: var(--panel-bg);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  padding: 20px;
  backdrop-filter: blur(10px);
}

.card-glass h3 {
  font-size: 15px;
  margin-bottom: 16px;
  color: var(--text-secondary);
  font-weight: 500;
}

/* ── Inputs ── */
.input-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 16px;
}

.input-group:last-child {
  margin-bottom: 0;
}

.input-group label {
  font-size: 12px;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.input-wrapper input,
.input-wrapper select {
  width: 100%;
  background: #0b0f19;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 12px;
  color: #fff;
  font-size: 16px;
  font-weight: 500;
  outline: none;
  transition: border-color 0.3s;
  font-family: 'Inter', sans-serif;
  appearance: none;
  -webkit-appearance: none;
}

.input-wrapper input:focus,
.input-wrapper select:focus {
  border-color: var(--accent-color);
}

/* ── Button ── */
.btn-calc {
  width: 100%;
  padding: 16px;
  border: none;
  border-radius: 14px;
  background: var(--gradient-main);
  color: #fff;
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.2s;
  font-family: 'Outfit', sans-serif;
  letter-spacing: 0.5px;
}

.btn-calc:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}

.btn-calc:active {
  transform: translateY(0);
}

/* ── Estilos checkboxes ── */
.styles-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-bottom: 16px;
}

.style-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  border: 1px solid transparent;
  border-radius: 10px;
  cursor: pointer;
  transition: filter 0.2s, transform 0.15s;
}

.style-item:hover {
  filter: brightness(1.15);
  transform: scale(1.02);
}

.style-item.checked {
  filter: brightness(1.05);
}

.style-item input[type="checkbox"] {
  accent-color: #fff;
  width: 16px;
  height: 16px;
  cursor: pointer;
  flex-shrink: 0;
}

.style-item label {
  font-size: 13px;
  cursor: pointer;
  font-weight: 600;
  color: #fff;
  text-shadow: 0 1px 3px rgba(0,0,0,0.5);
}

.btn-auto {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  background: transparent;
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s;
  font-family: 'Inter', sans-serif;
}

.btn-auto:hover {
  border-color: var(--accent-color);
  color: var(--accent-color);
}

.warning-text {
  color: #f87171;
  font-size: 13px;
  margin-top: 0;
  margin-bottom: 12px;
  font-weight: 500;
}

/* ── Result card ── */
.result-summary {
  padding: 28px;
  border-radius: 24px;
  text-align: center;
  background: var(--gradient-success);
  box-shadow: 0 10px 25px -5px rgba(245, 158, 11, 0.3);
  animation: fadeIn 0.5s ease-out;
  display: none;
}

.result-summary.visible {
  display: block;
}

.result-summary .result-label {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 1px;
  opacity: 0.85;
  font-family: 'Outfit', sans-serif;
}

.result-row {
  display: flex;
  justify-content: center;
  gap: 40px;
  margin-top: 16px;
  flex-wrap: wrap;
}

.result-item .value {
  font-size: 44px;
  font-weight: 800;
  font-family: 'Outfit', sans-serif;
  line-height: 1;
}

.result-item .unit {
  font-size: 13px;
  opacity: 0.8;
  margin-top: 4px;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.result-note {
  margin-top: 12px;
  font-size: 12px;
  opacity: 0.75;
}

/* ── Distribution grid ── */
.dist-section {
  animation: fadeIn 0.5s ease-out;
  display: none;
}

.dist-section.visible {
  display: block;
}

.dist-title {
  font-size: 15px;
  color: var(--text-secondary);
  margin-bottom: 14px;
  font-weight: 500;
}

.dist-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 12px;
}

.dist-card {
  background: var(--panel-bg);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 16px;
  text-align: center;
  animation: fadeIn 0.4s ease-out;
}

.dist-card .style-name {
  font-size: 13px;
  color: var(--accent-color);
  font-weight: 600;
  margin-bottom: 8px;
  font-family: 'Outfit', sans-serif;
}

.dist-card .pct {
  font-size: 28px;
  font-weight: 800;
  font-family: 'Outfit', sans-serif;
}

.dist-card .liters {
  font-size: 13px;
  color: var(--text-secondary);
  margin-top: 4px;
}

.dist-card .barrels {
  margin-top: 8px;
  padding-top: 8px;
  border-top: 1px solid var(--border-color);
  font-size: 12px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ── Links Section ── */
.links-section {
  margin-top: 8px;
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
}

.section-title {
  font-size: 16px;
  margin-bottom: 16px;
  color: var(--text-secondary);
}

.links-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
}

.link-card {
  background: var(--panel-bg);
  padding: 10px 14px;
  border-radius: 14px;
  text-decoration: none;
  color: #fff;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: transform 0.3s, background 0.2s;
}

.link-card:hover {
  transform: translateY(-2px);
  background: rgba(55, 65, 81, 0.7);
}

.link-info {
  min-width: 0;
  overflow: hidden;
  flex: 1;
}

.link-title {
  font-size: 13px;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  display: block;
}

.icon-arrow {
  flex-shrink: 0;
  opacity: 0.6;
}

/* ── Animations ── */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── Hide spinners ── */
input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  appearance: none;
  margin: 0;
}
input[type=number] {
  -moz-appearance: textfield;
  appearance: textfield;
}