: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, #10b981, #3b82f6);
}

* {
  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: 600px;
  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;
}

/* Tabs */
.tool-selector {
  display: flex;
  background: var(--panel-bg);
  padding: 6px;
  border-radius: 16px;
  position: relative;
  gap: 4px;
}

.tab-btn {
  flex: 1;
  padding: 12px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-weight: 600;
  cursor: pointer;
  z-index: 2;
  transition: color 0.3s;
  font-size: 15px;
}

.tab-btn.active {
  color: #fff;
}

.active-indicator {
  position: absolute;
  top: 6px;
  left: 6px;
  width: calc(50% - 8px);
  height: calc(100% - 12px);
  background: var(--gradient-main);
  border-radius: 12px;
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 1;
}

/* Calculator Sections */
.calculator-section {
  display: none;
  flex-direction: column;
  gap: 20px;
  animation: fadeIn 0.4s ease-out;
}

.calculator-section.active {
  display: flex;
}

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

/* 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;
}

.input-row {
  display: flex;
  gap: 12px;
}

.input-group {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.input-group.small {
  flex: 0 0 100px;
}

.input-group label {
  font-size: 13px;
  color: var(--text-secondary);
}

.input-wrapper input {
  width: 100%;
  background: #0b0f19;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 12px;
  color: #fff;
  font-size: 18px;
  font-weight: 600;
  outline: none;
  transition: border-color 0.3s;
}

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

/* Information displayed in sub */
.sub-result, .sub-info {
  margin-top: 12px;
  font-size: 14px;
  color: var(--text-secondary);
  display: flex;
  justify-content: space-between;
}

.sub-result span, .sub-info span {
  font-weight: 600;
  color: var(--accent-color);
}

/* Result Card */
.result-card {
  padding: 32px;
  border-radius: 24px;
  text-align: center;
  background: var(--gradient-success);
  box-shadow: 0 10px 25px -5px rgba(16, 185, 129, 0.4);
  animation: pulse 2s infinite;
}

.result-card span {
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 1px;
  opacity: 0.9;
}

.abv-value {
  font-size: 48px;
  font-weight: 800;
  font-family: 'Outfit', sans-serif;
  margin-top: 4px;
}

@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.02); }
  100% { transform: scale(1); }
}

/* Links Section */
.links-section {
  margin-top: 20px;
  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(auto-fit, minmax(120px, 1fr));
  gap: 12px;
}

.link-card {
  background: var(--panel-bg);
  padding: 16px;
  border-radius: 16px;
  text-decoration: none;
  color: #fff;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: transform 0.3s;
}

.link-card:hover {
  transform: translateX(4px);
  background: rgba(55, 65, 81, 0.7);
}

/* 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;
}