/* ==========================================================================
   Neon Pulse Calculator - Layout Styles (v3.0)
   ========================================================================== */

/* ===== Main Layout ===== */
.app {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: var(--space-lg);
  position: relative;
}

/* Background Effects */
.app::before {
  content: '';
  position: fixed;
  inset: 0;
  background: 
    radial-gradient(circle at 15% 15%, rgba(0, 245, 255, 0.025) 0%, transparent 45%),
    radial-gradient(circle at 85% 85%, rgba(178, 75, 255, 0.025) 0%, transparent 45%);
  pointer-events: none;
  z-index: -1;
}

/* ===== Container ===== */
.container {
  width: 100%;
  max-width: 580px;
  margin: 0 auto;
  transition: max-width 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== PC Mode ===== */
body.pc-mode .container {
  max-width: var(--pc-mode-width);
}

body.pc-mode .app {
  min-height: auto;
  padding: var(--space-md);
}

body.pc-mode .card {
  border-radius: var(--radius-xl);
  padding: var(--space-lg);
}

body.pc-mode .section-header {
  margin-bottom: var(--space-md);
}

body.pc-mode .section-title {
  font-size: var(--font-size-lg);
}

body.pc-mode .section-subtitle {
  font-size: var(--font-size-xs);
}

body.pc-mode .nav-tabs {
  margin-bottom: var(--space-md);
}

body.pc-mode .nav-tab-icon {
  font-size: var(--font-size-lg);
}

body.pc-mode .footer {
  margin-top: var(--space-lg);
  padding: var(--space-md);
}

/* ===== Glass Card ===== */
.card {
  background: rgba(255, 255, 255, 0.03);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid var(--color-glass-border);
  border-radius: var(--radius-2xl);
  padding: var(--space-xl);
  box-shadow: 
    var(--shadow-xl),
    inset 0 1px 0 rgba(255, 255, 255, 0.06);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--gradient-primary);
  opacity: 0.4;
}

/* ===== Navigation Tabs ===== */
.nav-tabs {
  display: flex;
  gap: var(--space-xs);
  margin-bottom: var(--space-xl);
  padding: var(--space-xs);
  background: rgba(0, 0, 0, 0.3);
  border-radius: var(--radius-2xl);
  position: relative;
}

.nav-tab {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-lg);
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-medium);
  transition: all var(--transition-base);
  position: relative;
  z-index: 1;
}

.nav-tab:hover {
  color: var(--color-text-primary);
  background: var(--color-glass-hover);
}

.nav-tab.active {
  color: var(--color-text-primary);
  background: var(--gradient-primary);
  box-shadow: var(--shadow-neon-cyan);
}

.nav-tab-icon {
  font-size: var(--font-size-2xl);
  line-height: 1;
}

.nav-tab-label {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
}

.nav-tab-sublabel {
  font-size: 0.65rem;
  color: var(--color-text-muted);
  opacity: 0.7;
}

.nav-tab.active .nav-tab-sublabel {
  color: var(--color-text-secondary);
}

/* ===== Section Container ===== */
.section {
  display: none;
  animation: sectionFadeIn 0.35s ease-out;
}

.section.active {
  display: block;
}

@keyframes sectionFadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ===== Section Header ===== */
.section-header {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.section-title {
  margin-bottom: 2px;
}

.section-subtitle {
  color: var(--color-text-secondary);
  font-size: var(--font-size-xs);
}

/* ===== Form Layout ===== */
.form {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.form-row {
  display: flex;
  gap: var(--space-sm);
}

.form-row > * {
  flex: 1;
}

/* ===== Calculator Grid ===== */
.calculator-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-xs);
}

.calculator-display {
  grid-column: span 4;
}

.calculator-btn-wide {
  grid-column: span 2;
}

.calculator-btn-full {
  grid-column: span 4;
}

/* ===== Result Container ===== */
.result-container {
  margin-top: var(--space-lg);
  padding: var(--space-md);
  background: rgba(0, 245, 255, 0.04);
  border: 1px solid rgba(0, 245, 255, 0.15);
  border-radius: var(--radius-lg);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.result-container::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--gradient-primary);
  opacity: 0.03;
  pointer-events: none;
}

.result-label {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2xs);
}

.result-value {
  font-family: var(--font-family-mono);
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-neon-cyan);
  text-shadow: 0 0 15px rgba(0, 245, 255, 0.4);
  word-break: break-all;
  overflow-wrap: break-word;
}

/* ===== History Panel ===== */
.history-panel {
  margin-top: var(--space-md);
  max-height: 180px;
  overflow-y: auto;
  background: rgba(0, 0, 0, 0.2);
  border-radius: var(--radius-lg);
  padding: var(--space-sm);
}

.history-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-xs) var(--space-sm);
  background: var(--color-glass-white);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-2xs);
  font-family: var(--font-family-mono);
  font-size: var(--font-size-xs);
  transition: var(--transition-fast);
  cursor: pointer;
}

.history-item:hover {
  background: var(--color-glass-hover);
  transform: translateX(-2px);
}

.history-item:last-child { margin-bottom: 0; }

.history-expression { color: var(--color-text-secondary); }
.history-equals { color: var(--color-text-muted); margin: 0 var(--space-xs); }
.history-result { color: var(--color-neon-cyan); font-weight: var(--font-weight-semibold); }

.history-empty {
  text-align: center;
  padding: var(--space-md);
  color: var(--color-text-muted);
  font-size: var(--font-size-xs);
}

/* ===== Utility Classes ===== */
.hidden { display: none !important; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border-width: 0; }
.text-center { text-align: center; }
.text-gradient { background: var(--gradient-primary); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }