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

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont;
  background: #e0e5ec;
  min-height: 100vh;
}

.header {
  background: #e0e5ec;
  padding: 20px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}
.header-content {
  max-width: 420px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.header-left,
.header-center,
.header-right {
  flex: 1;
}
.header-left {
  display: flex;
  justify-content: flex-start;
}
.header-center {
  display: flex;
  justify-content: center;
}
.header-right {
  display: flex;
  justify-content: flex-end;
}
.back-btn {
  background: #e0e5ec;
  border: none;
  width: 45px;
  height: 45px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 6px 6px 12px #bec3c9, -6px -6px 12px #ffffff;
  transition: all 0.1s ease;
}
.back-btn:active {
  box-shadow: inset 6px 6px 12px #bec3c9, inset -6px -6px 12px #ffffff;
}
.back-btn svg {
  width: 24px;
  height: 24px;
  fill: #4a5568;
}
.header-logo {
  width: 45px;
  height: 45px;
  background: #e0e5ec;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 6px 6px 12px #bec3c9, -6px -6px 12px #ffffff;
  font-size: 24px;
}
.header-title {
  font-size: 16px;
  font-weight: bold;
  color: #4a5568;
  display: flex;
  flex-direction: column;
  align-items: center;
  line-height: 1.2;
}
.header-title span {
  display: block;
}

.main {
  padding: 20px;
  display: flex;
  justify-content: center;
}
.container {
  width: 100%;
  max-width: 520px;
}

.card {
  background: #e0e5ec;
  border-radius: 28px;
  padding: 24px;
  box-shadow: 18px 18px 40px #bec3c9, -18px -18px 40px #fff;
}

.input-wrap {
  margin-bottom: 20px;
}
.input-wrap input {
  background: #e0e5ec;
  width: 100%;
  padding: 14px;
  border-radius: 16px;
  text-align: center;
  font-size: 18px;
  border: none;
  font-size: 15px;
  box-shadow: inset 5px 5px 10px #cfd5dd, inset -5px -5px 10px #ffffff;
  outline: none;
}

.palette-grid {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 20px;
}

.palette-box {
  width: 100%;
  height: 64px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 700;
  color: #fff;
  cursor: pointer;
  text-shadow: 0 0 4px rgba(0, 0, 0, 0.6);
}

.palette-box {
  height: 70px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 12px;
  font-weight: 600;
  color: #fff;
  text-shadow: 0 0 3px rgba(0, 0, 0, 0.7);
  user-select: none;
  transition: transform 0.15s;
}
.palette-box:active {
  transform: scale(0.95);
}

.btn-row {
  display: flex;
  gap: 10px;
  width: 100%;
  margin-top: 1.2rem;
  margin-bottom: 10px;
}
.btn {
  width: 100%;
  padding: 14px;
  border-radius: 18px;
  border: none;
  cursor: pointer;
  font-weight: 700;
  background: #e0e5ec;
  color: #2d3748;
  box-shadow: 8px 8px 18px #bec3c9, -8px -8px 18px #fff;
}
.btn:active {
  box-shadow: inset 8px 8px 18px #bec3c9, inset -8px -8px 18px #fff;
}
.btn.primary {
  background: linear-gradient(135deg, #667eea, #764ba2);
  color: #fff;
}