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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Noto Sans JP", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: #333;
  background: #f0f2f5;
}

/* ===== HEADER ===== */
header {
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
  color: #fff;
  padding: 1.5rem 1rem;
  text-align: center;
}

header h1 {
  font-size: 1.2rem;
  font-weight: 700;
  line-height: 1.4;
}

.subtitle {
  font-size: 0.85rem;
  opacity: 0.8;
  margin-top: 0.375rem;
}

/* ===== MAIN ===== */
main {
  max-width: 800px;
  margin: 0 auto;
  padding: 1rem;
}

/* ===== AD UNIT ===== */
.ad-unit {
  margin: 1.25rem 0;
}

/* ===== STEP BLOCK ===== */
.step-block {
  background: #fff;
  border-radius: 12px;
  padding: 1.25rem 1rem;
  margin-bottom: 1rem;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.07);
}

.step-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1rem;
  font-weight: 700;
  color: #1a1a2e;
  margin-bottom: 1rem;
}

.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  min-width: 28px;
  background: #e94560;
  color: #fff;
  border-radius: 50%;
  font-size: 0.85rem;
  font-weight: 700;
}

/* ===== DROP ZONE ===== */
.drop-zone {
  position: relative;
  border: 2px dashed #b0b8c8;
  border-radius: 10px;
  padding: 2rem 1rem;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
  background: #f7f9fc;
}

.drop-zone:hover,
.drop-zone:focus,
.drop-zone.drag-over {
  border-color: #e94560;
  background: #fff0f3;
  outline: none;
}

.drop-zone input[type="file"] {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
}

.drop-icon {
  color: #b0b8c8;
  margin-bottom: 0.5rem;
}

.drop-zone:hover .drop-icon,
.drop-zone.drag-over .drop-icon {
  color: #e94560;
}

.drop-text {
  font-size: 0.95rem;
  font-weight: 600;
  color: #444;
}

.drop-sub {
  font-size: 0.8rem;
  color: #999;
  margin-top: 0.25rem;
}

/* ===== FILE INFO ===== */
.file-info {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  background: #eaf4ff;
  border-radius: 8px;
  padding: 0.6rem 0.875rem;
  margin-top: 0.75rem;
  font-size: 0.9rem;
  flex-wrap: wrap;
}

.file-name {
  flex: 1;
  min-width: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  color: #1a5fad;
  font-weight: 600;
}

.btn-clear {
  background: none;
  border: 1px solid #ccc;
  border-radius: 6px;
  padding: 0.3rem 0.65rem;
  font-size: 0.8rem;
  cursor: pointer;
  color: #666;
  min-height: 44px;
  transition: background 0.15s;
  white-space: nowrap;
}

.btn-clear:hover {
  background: #f5f5f5;
}

/* ===== DIVIDER OR ===== */
.divider-or {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin: 1rem 0;
  color: #bbb;
  font-size: 0.85rem;
}

.divider-or::before,
.divider-or::after {
  content: "";
  flex: 1;
  height: 1px;
  background: #e0e0e0;
}

/* ===== MIC BUTTON ===== */
.btn-mic {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  width: 100%;
  min-height: 44px;
  padding: 0.65rem 1rem;
  font-size: 0.95rem;
  font-weight: 600;
  background: #fff;
  color: #444;
  border: 2px solid #ccc;
  border-radius: 8px;
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s, background 0.2s;
}

.btn-mic:hover {
  border-color: #e94560;
  color: #e94560;
  background: #fff0f3;
}

.btn-mic.active {
  background: #e94560;
  border-color: #e94560;
  color: #fff;
}

.mic-status {
  text-align: center;
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: #e94560;
  font-weight: 600;
}

/* ===== CONTROLS GRID ===== */
.controls-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.875rem;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.control-group label {
  font-size: 0.875rem;
  font-weight: 600;
  color: #444;
}

.control-group select,
.control-group input[type="text"] {
  width: 100%;
  padding: 0.6rem 0.75rem;
  font-size: 0.95rem;
  border: 1px solid #d0d5de;
  border-radius: 8px;
  background: #fafafa;
  min-height: 44px;
  transition: border-color 0.15s;
}

.control-group select:focus,
.control-group input[type="text"]:focus {
  outline: none;
  border-color: #e94560;
}

/* ===== COLOR ROW ===== */
.color-row {
  display: flex;
  align-items: center;
  gap: 0.625rem;
}

.color-row input[type="color"] {
  width: 44px;
  height: 44px;
  min-width: 44px;
  border: 2px solid #d0d5de;
  border-radius: 8px;
  padding: 2px;
  cursor: pointer;
  background: none;
}

.color-hex {
  font-size: 0.85rem;
  color: #666;
  font-family: monospace;
}

/* ===== DRAW BUTTON ===== */
.btn-draw {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  width: 100%;
  min-height: 52px;
  margin-top: 1.25rem;
  padding: 0.75rem 1rem;
  font-size: 1.05rem;
  font-weight: 700;
  background: linear-gradient(135deg, #e94560, #c73652);
  color: #fff;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.1s;
}

.btn-draw:hover:not(:disabled) {
  opacity: 0.9;
  transform: translateY(-1px);
}

.btn-draw:active:not(:disabled) {
  transform: translateY(0);
}

.btn-draw:disabled {
  background: #c8cdd6;
  cursor: not-allowed;
}

/* ===== CANVAS WRAPPER ===== */
.canvas-wrapper {
  position: relative;
  background: #1a1a2e;
  border-radius: 10px;
  overflow: hidden;
  min-height: 160px;
  display: flex;
  align-items: center;
  justify-content: center;
}

#waveCanvas {
  display: block;
  max-width: 100%;
  height: auto;
}

.canvas-placeholder {
  position: absolute;
  color: #555;
  font-size: 0.85rem;
  text-align: center;
  padding: 1rem;
  pointer-events: none;
}

/* ===== SAVE BUTTON ===== */
.btn-save {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  width: 100%;
  min-height: 52px;
  margin-top: 1rem;
  padding: 0.75rem 1rem;
  font-size: 1rem;
  font-weight: 700;
  background: linear-gradient(135deg, #0f3460, #16213e);
  color: #fff;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.1s;
}

.btn-save:hover:not(:disabled) {
  opacity: 0.88;
  transform: translateY(-1px);
}

.btn-save:active:not(:disabled) {
  transform: translateY(0);
}

.btn-save:disabled {
  background: #c8cdd6;
  cursor: not-allowed;
}

/* ===== HOWTO SECTION ===== */
.howto-section {
  background: #fff;
  border-radius: 12px;
  padding: 1.5rem 1rem;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.07);
  margin-bottom: 1rem;
}

.howto-section h2 {
  font-size: 1rem;
  font-weight: 700;
  color: #1a1a2e;
  margin-bottom: 0.75rem;
  margin-top: 1.5rem;
}

.howto-section h2:first-child {
  margin-top: 0;
}

.howto-section ol {
  padding-left: 1.375rem;
  color: #555;
  font-size: 0.9rem;
}

.howto-section li {
  margin-bottom: 0.6rem;
}

.howto-section p {
  font-size: 0.9rem;
  color: #555;
  line-height: 1.75;
}

/* ===== FOOTER ===== */
footer {
  text-align: center;
  padding: 2rem 1rem;
  font-size: 0.85rem;
  color: #888;
}

footer a {
  color: #666;
  text-decoration: none;
}

footer a:hover {
  text-decoration: underline;
}

/* ===== DESKTOP ===== */
@media (min-width: 640px) {
  header h1 {
    font-size: 1.6rem;
  }

  .subtitle {
    font-size: 0.9rem;
  }

  main {
    padding: 1.5rem 2rem;
  }

  .controls-grid {
    grid-template-columns: 1fr 1fr;
  }

  .step-block {
    padding: 1.75rem 1.5rem;
  }
}

@media (min-width: 900px) {
  .controls-grid {
    grid-template-columns: 1fr 1fr 1fr;
  }
}