/* ─── Brew Ratio Calculator — Coffee-themed Dark Design ─── */

:root {
  /* Palette — warm coffee tones */
  --bg-deep:     #13100D;
  --bg-surface:  #1E1A15;
  --bg-card:     #272118;
  --bg-card-alt: #2F281F;
  --border:      #3D3428;
  --border-light:#4A3E30;

  --accent:      #C8956C;
  --accent-dim:  #A07550;
  --accent-glow: rgba(200, 149, 108, 0.15);
  --accent-glow2:rgba(200, 149, 108, 0.06);

  --text:        #F0EBE4;
  --text-sub:    #A89B8C;
  --text-dim:    #7A6E60;

  --success:     #8BB06A;
  --radius:      12px;
  --radius-sm:   8px;
  --radius-lg:   16px;
  --font:        'Inter', -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
  --transition:  0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  font-family: var(--font);
  background: var(--bg-deep);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ─── Layout ─── */
.app-container {
  max-width: 520px;
  margin: 0 auto;
  padding: 24px 16px 40px;
}

/* ─── Header ─── */
.app-header {
  text-align: center;
  margin-bottom: 32px;
}

.header-top {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-bottom: 8px;
}

.app-header h1 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.02em;
}

.subheading {
  font-size: 0.875rem;
  color: var(--text-sub);
  max-width: 360px;
  margin: 0 auto;
}

#lang-select {
  appearance: none;
  background: var(--bg-card);
  color: var(--text-sub);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 4px 8px;
  font-size: 0.75rem;
  font-family: var(--font);
  font-weight: 600;
  cursor: pointer;
  transition: border-color var(--transition);
}

#lang-select:hover { border-color: var(--accent-dim); }

/* ─── Section ─── */
.section {
  margin-bottom: 24px;
}

.section-label {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  margin-bottom: 12px;
}

/* ─── Method Grid ─── */
.method-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 8px;
}

.method-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  padding: 12px 14px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all var(--transition);
  text-align: left;
  font-family: var(--font);
  color: var(--text);
}

.method-card:hover {
  border-color: var(--accent-dim);
  background: var(--bg-card-alt);
}

.method-card.active {
  border-color: var(--accent);
  background: var(--accent-glow);
  box-shadow: 0 0 0 1px var(--accent), inset 0 1px 0 rgba(255,255,255,0.04);
}

.method-icon {
  font-size: 1.25rem;
  line-height: 1;
  margin-bottom: 4px;
}

.method-name {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text);
}

.method-desc {
  font-size: 0.7rem;
  color: var(--text-dim);
  line-height: 1.3;
}

/* ─── Calculator ─── */
.calculator-section {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px 20px;
}

.calc-row {
  display: flex;
  align-items: flex-end;
  gap: 12px;
  margin-bottom: 24px;
}

.calc-field {
  flex: 1;
}

.calc-field label {
  display: block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-sub);
  margin-bottom: 6px;
}

.input-group {
  position: relative;
  display: flex;
  align-items: center;
}

.input-group input {
  width: 100%;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 12px 36px 12px 14px;
  font-size: 1.25rem;
  font-weight: 600;
  font-family: var(--font);
  color: var(--text);
  transition: all var(--transition);
  -moz-appearance: textfield;
}

.input-group input::-webkit-inner-spin-button,
.input-group input::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.input-group input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.input-group input.computed {
  color: var(--accent);
  background: var(--accent-glow2);
  border-color: var(--border);
  cursor: default;
}

.input-group .unit {
  position: absolute;
  right: 12px;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-dim);
  pointer-events: none;
}

/* Swap button */
.swap-btn {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 50%;
  color: var(--accent);
  font-size: 1.1rem;
  cursor: pointer;
  transition: all var(--transition);
  font-family: var(--font);
  margin-bottom: 2px;
}

.swap-btn:hover {
  background: var(--accent-glow);
  border-color: var(--accent);
  transform: rotate(180deg);
}

/* ─── Ratio Control ─── */
.ratio-control {
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

.ratio-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}

.ratio-header > span:first-child {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-sub);
}

.ratio-display {
  font-size: 1rem;
  color: var(--text);
}

.ratio-num {
  font-weight: 700;
  color: var(--accent);
  font-size: 1.125rem;
}

/* Range slider */
.slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  border-radius: 3px;
  background: var(--bg-card);
  outline: none;
  cursor: pointer;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent);
  border: 3px solid var(--bg-surface);
  box-shadow: 0 2px 8px rgba(0,0,0,0.3);
  cursor: pointer;
  transition: transform var(--transition);
}

.slider::-webkit-slider-thumb:hover {
  transform: scale(1.15);
}

.slider::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent);
  border: 3px solid var(--bg-surface);
  box-shadow: 0 2px 8px rgba(0,0,0,0.3);
  cursor: pointer;
}

.ratio-range-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.7rem;
  color: var(--text-dim);
  margin-top: 6px;
}

/* ─── Tips ─── */
.tips-section {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
}

.tips-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.tips-list li {
  position: relative;
  padding-left: 20px;
  font-size: 0.85rem;
  color: var(--text-sub);
  line-height: 1.5;
}

.tips-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 8px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent-dim);
}

/* ─── Footer ─── */
.app-footer {
  text-align: center;
  padding-top: 32px;
  color: var(--text-dim);
  font-size: 0.75rem;
}

/* ─── Responsive ─── */
@media (max-width: 400px) {
  .method-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .calc-row {
    flex-direction: column;
    align-items: stretch;
  }

  .swap-btn {
    align-self: center;
    transform: rotate(0deg);
  }

  .swap-btn:hover {
    transform: rotate(180deg);
  }

  .app-header h1 {
    font-size: 1.25rem;
  }
}