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

:root {
  --color-accent:  #008080;
  --color-bg:      #f5f5f7;
  --color-surface: #ffffff;
  --color-text:    #1d1d1f;
  --color-muted:   #6e6e73;
  --color-border:  #d2d2d7;
  --radius:        12px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ── Header ── */

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 32px;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.header-logo {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}

h1 {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.3px;
}

header p {
  font-size: 13px;
  color: var(--color-muted);
  margin-top: 2px;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.header-actions select {
  height: 36px;
  padding: 0 28px 0 10px;
  appearance: none;
  background-color: var(--color-bg);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%23888'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 13px;
  font-family: inherit;
  color: var(--color-text);
  outline: none;
  cursor: pointer;
  transition: border-color 0.15s;
}

.header-actions select:focus { border-color: var(--color-accent); }

#export-btn {
  height: 36px;
  padding: 0 16px;
  background: var(--color-accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 13px;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  white-space: nowrap;
  transition: opacity 0.15s;
}

#export-btn:hover:not(:disabled) { opacity: 0.85; }
#export-btn:disabled { opacity: 0.35; cursor: not-allowed; }

/* ── Layout ── */

main {
  flex: 1;
  display: grid;
  grid-template-columns: 280px 1fr 280px;
  gap: 24px;
  padding: 24px 32px;
  align-items: start;
}

/* ── Controls ── */

.controls {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  position: sticky;
  top: 65px;
  align-self: start;
  max-height: calc(100vh - 90px);
  overflow-y: auto;
}

/* ── How to use ── */

.how-to-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 16px 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  position: sticky;
  top: 65px;
  align-self: start;
}

.how-to-title {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--color-muted);
}

.how-to-intro {
  font-size: 12px;
  color: var(--color-muted);
  line-height: 1.6;
}

.how-to-intro strong {
  color: var(--color-text);
  font-weight: 600;
}

.how-to-steps {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-left: 16px;
  margin: 0;
}

.how-to-steps li {
  font-size: 12px;
  color: var(--color-muted);
  line-height: 1.5;
}

.how-to-steps li strong {
  color: var(--color-text);
  font-weight: 600;
}

.how-to-privacy {
  font-size: 11px;
  font-weight: 600;
  color: var(--color-accent);
}

.how-to-divider {
  border-top: 1px solid var(--color-border);
  margin-top: 2px;
}

.how-to-about {
  font-size: 11px;
  color: var(--color-muted);
  line-height: 1.6;
}

.how-to-about strong {
  color: var(--color-text);
  font-weight: 600;
}

.how-to-link {
  color: var(--color-accent);
  text-decoration: none;
}

.how-to-link:hover {
  text-decoration: underline;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.control-group[hidden] { display: none; }

.panel-divider {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 0;
}

.font-select {
  width: 100%;
  height: 32px;
  padding: 0 28px 0 10px;
  appearance: none;
  background-color: var(--color-bg);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%23888'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
  border: 1px solid var(--color-border);
  border-radius: 7px;
  font-size: 12px;
  font-family: inherit;
  color: var(--color-text);
  outline: none;
  cursor: pointer;
  transition: border-color 0.15s;
}

.font-select:focus { border-color: var(--color-accent); }

.control-label {
  font-size: 11px;
  font-weight: 600;
  color: var(--color-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.sub-label {
  font-size: 10px;
  font-weight: 600;
  color: var(--color-muted);
  text-transform: uppercase;
  letter-spacing: 0.4px;
}

.align-toggle {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 6px;
}

.bg-toggle {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
}

.bg-type-btn,
.placement-btn,
.align-btn,
.crop-btn {
  padding: 7px;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-size: 12px;
  font-family: inherit;
  background: var(--color-bg);
  color: var(--color-muted);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}

.bg-type-btn.active,
.placement-btn.active,
.align-btn.active,
.crop-btn.active {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #fff;
}

.color-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.color-row-3 {
  grid-template-columns: 1fr 1fr 1fr;
}

.gradient-angle-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.gradient-angle-val {
  font-size: 11px;
  color: var(--color-muted);
  min-width: 28px;
  text-align: right;
}

.color-label {
  display: flex;
  flex-direction: column;
  gap: 4px;
  font-size: 11px;
  color: var(--color-muted);
}

input[type="color"] {
  width: 100%;
  height: 36px;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 3px 5px;
  cursor: pointer;
  background: var(--color-bg);
}

input[type="range"] {
  width: 100%;
  accent-color: var(--color-accent);
  cursor: pointer;
}

/* ── Cards area ── */

.cards-area {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px;
  min-height: 420px;
  transition: outline 0.15s;
}

.cards-area.drag-over {
  outline: 2px dashed var(--color-accent);
  outline-offset: -6px;
}

.cards {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: flex-start;
}

/* ── Screenshot card ── */

.card-wrapper {
  display: flex;
  flex-direction: column;
  gap: 6px;
  width: 280px;
}

.card-input {
  padding: 8px 10px;
  border: 1px solid var(--color-border);
  border-radius: 7px;
  font-size: 13px;
  font-family: inherit;
  color: var(--color-text);
  background: var(--color-bg);
  outline: none;
  transition: border-color 0.15s;
}

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

.canvas-wrap {
  position: relative;
  margin-top: 6px;
  cursor: pointer;
  border-radius: var(--radius);
}

.card-canvas {
  display: block;
  border-radius: var(--radius);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.12);
}

.canvas-replace-hint {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.5);
  color: #fff;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.2px;
  opacity: 0;
  transition: opacity 0.15s;
  border-radius: var(--radius);
  pointer-events: none;
}

.canvas-wrap:hover .canvas-replace-hint { opacity: 1; }

.card-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-top: 8px;
}

.card-btn {
  padding: 6px;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-size: 11px;
  font-family: inherit;
  color: var(--color-muted);
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s;
}

.card-remove         { border-color: #e88; color: #c44; }
.card-remove:hover   { border-color: #c44; background: rgba(204,68,68,0.08); }
.card-download:hover { border-color: var(--color-accent); color: var(--color-accent); }

/* ── Empty state ── */

.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 320px;
  border: 2px dashed var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
  color: var(--color-muted);
  transition: border-color 0.15s, color 0.15s;
}

.empty-state:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.empty-icon {
  font-size: 36px;
  line-height: 1;
  font-weight: 300;
}

.empty-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text);
}

.empty-sub {
  font-size: 12px;
}

/* ── Upload button ── */

.add-btn {
  height: 36px;
  padding: 0 14px;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 13px;
  font-weight: 500;
  font-family: inherit;
  color: var(--color-text);
  cursor: pointer;
  white-space: nowrap;
  transition: border-color 0.15s, color 0.15s;
}

.add-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* ── Reset button ── */

.reset-btn {
  background: none;
  border: none;
  color: var(--color-muted);
  font-size: 11px;
  font-family: inherit;
  cursor: pointer;
  padding: 4px 0;
  text-align: center;
  width: 100%;
  transition: color 0.15s;
}

.reset-btn:hover { color: var(--color-text); }

/* ── Responsive ── */

@media (max-width: 900px) {
  main {
    grid-template-columns: 280px 1fr;
    padding: 16px;
  }
  .how-to-card {
    grid-column: 1 / -1;
    position: static;
  }
}

@media (max-width: 700px) {
  main {
    grid-template-columns: 1fr;
    padding: 16px;
  }
  .controls {
    position: static;
  }
  header {
    padding: 14px 16px;
    flex-wrap: wrap;
  }
}