/* ============================================
   beroasTT — BE ROAS TikTok Calculator
   Premium Mobile-First UI
   ============================================ */

/* --- Reset & Base --- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg: #0a0e1a;
  --card-bg: #111827;
  --card-border: #1e293b;
  --input-bg: #0f172a;
  --input-border: #334155;
  --input-focus: #6366f1;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #6366f1;
  --accent-glow: rgba(99, 102, 241, 0.25);
  --green: #22c55e;
  --green-bg: rgba(34, 197, 94, 0.1);
  --red: #ef4444;
  --red-bg: rgba(239, 68, 68, 0.1);
  --amber: #f59e0b;
  --amber-bg: rgba(245, 158, 11, 0.1);
  --radius: 14px;
  --radius-sm: 10px;
  --shadow: 0 4px 24px rgba(0,0,0,0.3);
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--bg);
  color: var(--text-primary);
  line-height: 1.5;
  min-height: 100vh;
  padding-bottom: env(safe-area-inset-bottom);
}

/* --- App Container --- */
.app-container {
  max-width: 480px;
  margin: 0 auto;
  padding: 0 16px 24px;
}

/* --- Header --- */
.app-header {
  text-align: center;
  padding: 28px 0 20px;
}

.app-header h1 {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, #6366f1, #8b5cf6, #a78bfa);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.app-header h1 sup {
  font-size: 0.6em;
  -webkit-text-fill-color: #6366f1;
}

.subtitle {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-top: 4px;
}

/* --- Sections --- */
.section {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 18px 16px 16px;
  margin-bottom: 14px;
  box-shadow: var(--shadow);
}

.section-title {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 14px;
}

.fee-note {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-bottom: 10px;
  margin-top: -8px;
  opacity: 0.7;
}

/* --- Toggle Row --- */
.toggle-row {
  display: flex;
  gap: 6px;
  margin-bottom: 14px;
  background: var(--input-bg);
  border: 1.5px solid var(--input-border);
  border-radius: var(--radius-sm);
  padding: 3px;
}

.toggle-btn {
  flex: 1;
  padding: 9px 10px;
  background: transparent;
  border: none;
  border-radius: 8px;
  color: var(--text-muted);
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  text-align: center;
}

.toggle-btn.active {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 2px 8px var(--accent-glow);
}

.toggle-btn:not(.active):hover {
  color: var(--text-primary);
}

/* --- Input Groups --- */
.input-group {
  margin-bottom: 12px;
}

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

.input-group label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 5px;
}

.input-group input[type="number"],
.input-group select {
  width: 100%;
  padding: 12px 14px;
  background: var(--input-bg);
  border: 1.5px solid var(--input-border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 1rem;
  font-weight: 500;
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
  -moz-appearance: textfield;
}

.input-group input[type="number"]::-webkit-outer-spin-button,
.input-group input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.input-group input[type="number"]:focus,
.input-group select:focus {
  border-color: var(--input-focus);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.input-group select {
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' fill='%2394a3b8'%3E%3Cpath d='M1 1l5 5 5-5'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 36px;
  cursor: pointer;
}

.input-with-unit {
  position: relative;
}

.input-with-unit input {
  padding-right: 44px;
}

.input-with-unit .unit {
  position: absolute;
  right: 14px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 600;
  pointer-events: none;
}

/* --- Fee Row (side by side) --- */
.fee-row {
  display: flex;
  gap: 10px;
  margin-bottom: 12px;
}

.fee-row .input-group.half {
  flex: 1;
  margin-bottom: 0;
}

/* --- Result Row (inline) --- */
.result-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 12px;
  background: rgba(99, 102, 241, 0.08);
  border: 1px solid rgba(99, 102, 241, 0.2);
  border-radius: var(--radius-sm);
  margin-top: 2px;
}

.result-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.result-value {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
}

/* --- Results Section --- */
.results-section {
  border-color: rgba(99, 102, 241, 0.3);
  background: linear-gradient(180deg, rgba(99, 102, 241, 0.06), transparent);
}

.result-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.result-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 12px;
  background: rgba(255,255,255,0.03);
  border-radius: var(--radius-sm);
}

.result-item .result-label {
  font-size: 0.8rem;
}

.result-item .result-value {
  font-size: 1rem;
}

.result-value.profit {
  color: var(--green);
}

.result-value.highlight {
  color: var(--accent);
  font-size: 1.4rem;
  font-weight: 800;
}

.result-item.be-roas {
  background: var(--accent-glow);
  border: 1px solid rgba(99, 102, 241, 0.3);
  padding: 14px 16px;
}

.result-divider {
  height: 1px;
  background: var(--card-border);
  margin: 4px 0;
}

/* --- Preset Buttons --- */
.preset-hint {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 10px;
}

.preset-grid {
  display: flex;
  gap: 8px;
  margin-bottom: 8px;
  flex-wrap: wrap;
}

.preset-grid.s2 {
  margin-bottom: 0;
}

.preset-btn {
  flex: 1;
  min-width: 60px;
  padding: 10px 6px;
  background: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 0.78rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  text-align: center;
}

.preset-btn:active {
  transform: scale(0.96);
}

.preset-btn:hover {
  border-color: var(--accent);
  color: var(--text-primary);
}

.preset-btn.s2 {
  border-color: rgba(245, 158, 11, 0.3);
  color: var(--amber);
}

.preset-btn.s2:hover {
  border-color: var(--amber);
  background: var(--amber-bg);
}

/* --- Multi-Variant Section --- */
.multi-section {
  border-color: rgba(34, 197, 94, 0.2);
}

.multi-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
}

.multi-row.header-row {
  padding: 0 4px;
  margin-bottom: 6px;
}

.multi-label {
  width: 60px;
  flex-shrink: 0;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--text-muted);
}

.multi-input-label {
  flex: 1;
  font-size: 0.7rem;
  color: var(--text-muted);
  text-align: center;
}

.multi-individual-roas {
  width: 60px;
  flex-shrink: 0;
  font-size: 0.7rem;
  color: var(--text-muted);
  text-align: right;
}

.multi-row .input-group {
  flex: 1;
  margin-bottom: 0;
}

.multi-row .input-group input {
  padding: 10px 10px;
  text-align: center;
  font-size: 0.9rem;
}

.multi-row .variant-label {
  width: 60px;
  flex-shrink: 0;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.multi-row .variant-roas {
  width: 60px;
  flex-shrink: 0;
  font-size: 0.78rem;
  color: var(--text-muted);
  text-align: right;
}

.multi-result {
  margin-top: 12px;
}

/* --- Footer --- */
.app-footer {
  text-align: center;
  padding: 20px 0 8px;
}

.app-footer p {
  font-size: 0.72rem;
  color: var(--text-muted);
}

/* --- Responsive --- */
@media (min-width: 481px) {
  .app-container {
    padding: 0 24px 32px;
  }

  .section {
    padding: 22px 20px 20px;
  }
}

/* --- Dark scrollbar --- */
::-webkit-scrollbar {
  width: 4px;
}
::-webkit-scrollbar-track {
  background: var(--bg);
}
::-webkit-scrollbar-thumb {
  background: var(--card-border);
  border-radius: 2px;
}