/* 基础设置：无构建语法，所有本地资源使用相对路径 */
:root {
  color-scheme: light;
  --navy: #123455;
  --navy-dark: #0b233b;
  --border: #cbd5e1;
}

* {
  box-sizing: border-box;
}

html {
  scroll-padding-top: 110px;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.6;
}

img {
  display: block;
  max-width: 100%;
  background: #e2e8f0;
}

button,
input,
select,
textarea {
  font: inherit;
}

button,
a,
summary,
input,
select,
textarea {
  -webkit-tap-highlight-color: transparent;
}

/* 键盘焦点提示 */
:focus-visible {
  outline: 3px solid #0284c7;
  outline-offset: 4px;
}

section[id] {
  scroll-margin-top: 110px;
}

.nav-link {
  color: var(--navy);
  font-weight: 500;
  text-decoration: none;
}

.nav-link:hover {
  text-decoration: underline;
  text-underline-offset: 5px;
}

.button-primary,
.button-secondary {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  padding: 12px 22px;
  border: 1px solid var(--navy);
  border-radius: 8px;
  font-weight: 600;
  line-height: 1.4;
  text-align: center;
  text-decoration: none;
  cursor: pointer;
}

.button-primary {
  background: var(--navy);
  color: white;
}

.button-primary:hover {
  background: var(--navy-dark);
}

.button-secondary {
  background: white;
  color: var(--navy);
}

.button-secondary:hover {
  background: #f1f5f9;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.6;
}

.section-label {
  color: #475569;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.12em;
}

.section-title {
  margin-top: 12px;
  color: var(--navy);
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.025em;
}

.field-label {
  display: block;
  margin-bottom: 7px;
  color: var(--navy);
  font-size: 14px;
  font-weight: 600;
}

.form-field {
  display: block;
  width: 100%;
  min-width: 0;
  min-height: 48px;
  padding: 11px 12px;
  border: 1px solid var(--border);
  border-radius: 7px;
  background: white;
  color: #1e293b;
}

.form-field::placeholder {
  color: #64748b;
}

textarea.form-field {
  resize: vertical;
}

/* 菜单使用原生展开功能，无花哨动画 */
summary {
  list-style: none;
}

summary::-webkit-details-marker {
  display: none;
}

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 100;
  padding: 12px 18px;
  transform: translateY(-160%);
  border-radius: 6px;
  background: var(--navy);
  color: white;
}

.skip-link:focus {
  transform: translateY(0);
}

#product:focus {
  border-color: #0284c7;
}

@media (max-width: 420px) {
  .button-primary,
  .button-secondary {
    padding-inline: 16px;
  }
}