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

:root {
  --color-bg: #ffffff;
  --color-bg-secondary: #f5f5f2;
  --color-bg-tertiary: #ebebeb;
  --color-text-primary: #1a1a18;
  --color-text-secondary: #6b6b67;
  --color-border: rgba(0, 0, 0, 0.12);
  --color-border-md: rgba(0, 0, 0, 0.22);
  --color-accent: #BA7517;
  --color-accent-bg: #FAEEDA;
  --color-accent-border: #BA7517;
  --radius-md: 8px;
  --radius-lg: 12px;
  --font-sans: "Sarabun", "Noto Sans Thai", system-ui, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #1c1c1a;
    --color-bg-secondary: #252521;
    --color-bg-tertiary: #2e2e2a;
    --color-text-primary: #f0ede8;
    --color-text-secondary: #9e9b96;
    --color-border: rgba(255, 255, 255, 0.12);
    --color-border-md: rgba(255, 255, 255, 0.22);
    --color-accent-bg: #2e2010;
  }
}

body {
  font-family: var(--font-sans);
  background: var(--color-bg-secondary);
  color: var(--color-text-primary);
  font-size: 15px;
  line-height: 1.6;
  min-height: 100vh;
}

/* ==============================
   Layout
   ============================== */
.app {
  max-width: 680px;
  margin: 0 auto;
  padding: 2rem 1rem 4rem;
}

.header {
  text-align: center;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 0.5px solid var(--color-border);
}

.header h1 {
  font-size: 24px;
  font-weight: 500;
  color: var(--color-text-primary);
  margin-bottom: 4px;
}

.header p {
  font-size: 13px;
  color: var(--color-text-secondary);
}

/* ==============================
   Card
   ============================== */
.card {
  background: var(--color-bg);
  border: 0.5px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  margin-bottom: 1rem;
}

/* ==============================
   Labels
   ============================== */
.section-label {
  font-size: 11px;
  font-weight: 500;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 10px;
}

/* ==============================
   Region & days row
   ============================== */
.region-row {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 1.25rem;
}

.region-row label {
  font-size: 13px;
  color: var(--color-text-secondary);
  white-space: nowrap;
}

.region-row select,
.region-row input[type="number"] {
  font-size: 14px;
  padding: 6px 10px;
  border: 0.5px solid var(--color-border-md);
  border-radius: var(--radius-md);
  background: var(--color-bg);
  color: var(--color-text-primary);
  flex: 1;
}

.region-row select {
  cursor: pointer;
}

/* ==============================
   Preset buttons
   ============================== */
.preset-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 1.25rem;
}

.preset-btn {
  font-size: 12px;
  padding: 4px 12px;
  border-radius: 20px;
  border: 0.5px solid var(--color-border-md);
  background: var(--color-bg-secondary);
  cursor: pointer;
  color: var(--color-text-secondary);
  white-space: nowrap;
  transition: background 0.15s, color 0.15s;
}

.preset-btn:hover {
  background: var(--color-bg-tertiary);
  color: var(--color-text-primary);
}

/* ==============================
   Appliance table
   ============================== */
.col-headers {
  display: grid;
  grid-template-columns: 1fr 80px 80px 64px 36px;
  gap: 8px;
  margin-bottom: 4px;
}

.col-label {
  font-size: 11px;
  color: var(--color-text-secondary);
}

.col-label.center {
  text-align: center;
}

.appliance-row {
  display: grid;
  grid-template-columns: 1fr 80px 80px 64px 36px;
  gap: 8px;
  align-items: center;
  margin-bottom: 8px;
}

.appliance-row input[type="text"],
.appliance-row input[type="number"] {
  width: 100%;
  font-size: 14px;
  padding: 6px 8px;
  border: 0.5px solid var(--color-border-md);
  border-radius: var(--radius-md);
  background: var(--color-bg);
  color: var(--color-text-primary);
  outline: none;
  transition: border-color 0.15s;
}

.appliance-row input[type="number"] {
  text-align: right;
}

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

.add-btn {
  font-size: 13px;
  color: var(--color-accent);
  border: none;
  background: none;
  cursor: pointer;
  padding: 4px 0;
  margin-top: 4px;
}

.add-btn:hover {
  text-decoration: underline;
}

.del-btn {
  font-size: 18px;
  color: var(--color-text-secondary);
  border: none;
  background: none;
  cursor: pointer;
  line-height: 1;
  opacity: 0.55;
  transition: opacity 0.15s;
}

.del-btn:hover {
  opacity: 1;
  color: #c0392b;
}

/* ==============================
   Summary metrics
   ============================== */
.summary-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-bottom: 1.25rem;
}

.metric {
  background: var(--color-bg-secondary);
  border-radius: var(--radius-md);
  padding: 12px;
  text-align: center;
}

.metric-label {
  font-size: 12px;
  color: var(--color-text-secondary);
  margin-bottom: 4px;
}

.metric-value {
  font-size: 22px;
  font-weight: 500;
  color: var(--color-text-primary);
}

.metric-unit {
  font-size: 12px;
  color: var(--color-text-secondary);
  margin-top: 2px;
}

/* ==============================
   Rate breakdown table
   ============================== */
.rate-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 6px 0;
  border-bottom: 0.5px solid var(--color-border);
  font-size: 13px;
  color: var(--color-text-primary);
}

.rate-row:last-child {
  border: none;
  font-weight: 500;
  font-size: 14px;
}

.rate-row .accent {
  color: var(--color-accent);
}

/* ==============================
   Bar chart
   ============================== */
.bar-wrap {
  margin-top: 8px;
}

.bar-section-label {
  font-size: 11px;
  font-weight: 500;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-top: 12px;
  margin-bottom: 8px;
}

.bar-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 7px;
  font-size: 12px;
}

.bar-name {
  min-width: 120px;
  color: var(--color-text-secondary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.bar-bg {
  flex: 1;
  height: 8px;
  background: var(--color-bg-tertiary);
  border-radius: 4px;
  overflow: hidden;
}

.bar-fill {
  height: 100%;
  background: var(--color-accent);
  border-radius: 4px;
  transition: width 0.4s ease;
}

.bar-val {
  min-width: 60px;
  text-align: right;
  color: var(--color-text-secondary);
}

/* ==============================
   AI button & output
   ============================== */
.ai-btn {
  width: 100%;
  margin-top: 1rem;
  padding: 10px 16px;
  border-radius: var(--radius-md);
  border: 0.5px solid var(--color-accent-border);
  background: transparent;
  color: var(--color-accent);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s;
  font-family: var(--font-sans);
}

.ai-btn:hover:not(:disabled) {
  background: var(--color-accent-bg);
}

.ai-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.ai-result {
  background: var(--color-bg-secondary);
  border-radius: var(--radius-md);
  padding: 1rem;
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.8;
  color: var(--color-text-primary);
}

.ai-result p {
  margin-bottom: 6px;
}