/* ==========================================================================
   爱加速 — 基础重置与设计变量（foundation.css）
   ========================================================================== */

:root {
    /* 主色：深蓝 */
    --brand-50: #eef4ff;
    --brand-100: #dbe7ff;
    --brand-200: #bcd2ff;
    --brand-500: #2563eb;
    --brand-600: #1d4ed8;
    --brand-700: #1e40af;

    /* 辅助色 */
    --accent-50: #ecfdf5;
    --accent-500: #10b981;
    --accent-600: #059669;

    /* 中性色 */
    --bg: #ffffff;
    --bg-soft: #f6f8fb;
    --bg-muted: #eef2f7;
    --text: #1a1a1a;
    --text-secondary: #5b6572;
    --text-tertiary: #8a94a3;
    --border: #e5e7eb;
    --border-strong: #d5dbe3;

    /* 圆角 */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-pill: 999px;

    /* 阴影 */
    --shadow-sm: 0 1px 2px rgba(16, 24, 40, .05);
    --shadow-md: 0 12px 28px -16px rgba(16, 24, 40, .22);
    --shadow-lg: 0 28px 56px -28px rgba(37, 99, 235, .38);

    /* 布局 */
    --container: 1200px;
    --gutter: 24px;
    --header-h: 68px;
    --section-y: 96px;
}

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

html {
    -webkit-text-size-adjust: 100%;
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB",
        "Microsoft YaHei", "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
    font-size: 1rem;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

h1,
h2,
h3,
h4,
p,
figure,
blockquote {
    margin: 0;
}

h1,
h2,
h3,
h4 {
    color: var(--text);
    line-height: 1.25;
    letter-spacing: -.01em;
}

h1 {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
}

h2 {
    font-size: clamp(1.5rem, 2.6vw, 2rem);
    font-weight: 700;
}

h3 {
    font-size: 1.125rem;
    font-weight: 600;
}

ul,
ol {
    margin: 0;
    padding: 0;
    list-style: none;
}

img,
svg {
    display: block;
    max-width: 100%;
}

img {
    height: auto;
}

a {
    color: var(--brand-600);
    text-decoration: none;
}

a:hover {
    color: var(--brand-700);
}

button {
    font: inherit;
    color: inherit;
    background: none;
    border: 0;
    cursor: pointer;
}

:focus-visible {
    outline: 2px solid var(--brand-500);
    outline-offset: 3px;
    border-radius: 4px;
}

.container {
    width: 100%;
    max-width: var(--container);
    margin-inline: auto;
    padding-inline: var(--gutter);
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    margin: -1px;
    padding: 0;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
    border: 0;
}

@media (max-width: 767px) {
    :root {
        --section-y: 64px;
        --gutter: 18px;
    }
}