/**
 * 文思 · 产品介绍页 + 登录注册页 共用视觉（参考有道宝库类 AI 产品落地：顶栏 + 大留白 + 渐变与玻璃卡片）
 * 与 theme.js 的 body.theme-dark / body.theme-light 协同。
 */
:root {
    --si-font: "Microsoft YaHei", "PingFang SC", "Noto Sans SC", system-ui, sans-serif;
    --si-radius-lg: 20px;
    --si-radius-md: 12px;
    --si-topbar-h: 56px;
}

body.site-landing,
body.site-auth {
    margin: 0;
    min-height: 100vh;
    font-family: var(--si-font);
    -webkit-tap-highlight-color: transparent;
}

/* ========== 顶栏 ========== */
.site-topbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 50;
    height: var(--si-topbar-h);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 max(20px, env(safe-area-inset-right, 0px)) 0 max(20px, env(safe-area-inset-left, 0px));
    padding-top: env(safe-area-inset-top, 0px);
    min-height: calc(var(--si-topbar-h) + env(safe-area-inset-top, 0px));
    box-sizing: border-box;
    border-bottom: 1px solid transparent;
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
}

body.theme-dark .site-topbar {
    background: rgba(6, 10, 28, 0.72);
    border-bottom-color: rgba(120, 160, 255, 0.12);
    color: #e2e8f0;
}

body.theme-light .site-topbar {
    background: rgba(255, 255, 255, 0.78);
    border-bottom-color: rgba(99, 68, 212, 0.12);
    color: #1e1b2e;
}

.site-topbar__brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 17px;
    letter-spacing: 0.04em;
}

.site-topbar__actions {
    display: flex;
    align-items: center;
    gap: 10px;
}

.site-topbar a.site-link {
    color: inherit;
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    padding: 8px 12px;
    border-radius: 10px;
    opacity: 0.92;
}

body.theme-dark .site-topbar a.site-link:hover {
    background: rgba(255, 255, 255, 0.08);
    opacity: 1;
}

body.theme-light .site-topbar a.site-link:hover {
    background: rgba(99, 68, 212, 0.1);
    opacity: 1;
}

.site-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 9px 18px;
    border-radius: 999px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    border: 1px solid transparent;
    text-decoration: none;
    font-family: inherit;
    transition: transform 0.15s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.site-btn:active {
    transform: scale(0.98);
}

.site-btn--ghost {
    background: transparent;
    border-color: rgba(147, 197, 253, 0.35);
    color: #dbeafe;
}

body.theme-light .site-btn--ghost {
    border-color: rgba(99, 68, 212, 0.28);
    color: #4338ca;
}

.site-btn--primary {
    background: linear-gradient(120deg, #4f6dff, #7c5cff);
    color: #fff;
    border-color: rgba(255, 255, 255, 0.2);
    box-shadow: 0 6px 20px rgba(79, 109, 255, 0.35);
}

.site-btn--primary:hover {
    box-shadow: 0 8px 26px rgba(79, 109, 255, 0.45);
}

.site-theme-pill {
    border: 1px solid rgba(147, 197, 253, 0.35);
    background: rgba(255, 255, 255, 0.06);
    color: #dbeafe;
    font-size: 12px;
    padding: 6px 12px;
    border-radius: 999px;
    cursor: pointer;
    font-family: inherit;
}

body.theme-light .site-theme-pill {
    border-color: rgba(99, 68, 212, 0.22);
    background: rgba(99, 68, 212, 0.08);
    color: #4338ca;
}

.site-theme-pill[aria-pressed="true"] {
    border-color: rgba(129, 140, 248, 0.85);
    box-shadow: 0 0 0 1px rgba(129, 140, 248, 0.35);
}

/* ========== 落地页主区 ========== */
.site-landing-main {
    padding-top: calc(var(--si-topbar-h) + env(safe-area-inset-top, 0px) + 32px);
    padding-bottom: 64px;
    padding-left: max(24px, env(safe-area-inset-left, 0px));
    padding-right: max(24px, env(safe-area-inset-right, 0px));
    max-width: 1120px;
    margin: 0 auto;
}

body.theme-dark.site-landing {
    color: #e8eef8;
    background: radial-gradient(120% 80% at 10% 0%, rgba(91, 108, 255, 0.22), transparent 55%),
        radial-gradient(90% 70% at 90% 20%, rgba(139, 92, 246, 0.18), transparent 50%),
        linear-gradient(180deg, #070a18 0%, #0a0f24 40%, #060814 100%);
    min-height: 100vh;
}

body.theme-light.site-landing {
    color: #1a1528;
    background: radial-gradient(120% 80% at 8% 0%, rgba(99, 68, 212, 0.12), transparent 55%),
        radial-gradient(90% 70% at 92% 10%, rgba(129, 140, 248, 0.14), transparent 48%),
        linear-gradient(180deg, #f8f7ff 0%, #eef2ff 45%, #f4f6fb 100%);
    min-height: 100vh;
}

.site-hero {
    text-align: center;
    margin-bottom: 56px;
}

.site-hero h1 {
    margin: 0 0 16px;
    font-size: clamp(32px, 5vw, 46px);
    font-weight: 800;
    letter-spacing: 0.02em;
    line-height: 1.2;
}

body.theme-dark .site-hero h1 {
    text-shadow: 0 8px 40px rgba(0, 0, 0, 0.45);
}

.site-hero .lead {
    margin: 0 auto 28px;
    max-width: 640px;
    font-size: 17px;
    line-height: 1.75;
    opacity: 0.92;
}

.site-hero__cta {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    justify-content: center;
    align-items: center;
}

.site-hero__hint {
    margin-top: 14px;
    font-size: 13px;
    opacity: 0.75;
}

.site-section-title {
    font-size: 13px;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    opacity: 0.55;
    margin: 0 0 18px;
    text-align: center;
}

.site-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 18px;
}

.site-card {
    border-radius: var(--si-radius-md);
    padding: 22px 20px;
    text-align: left;
    border: 1px solid transparent;
    transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

body.theme-dark .site-card {
    background: rgba(12, 18, 42, 0.55);
    border-color: rgba(120, 170, 255, 0.14);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.25);
}

body.theme-light .site-card {
    background: rgba(255, 255, 255, 0.82);
    border-color: rgba(99, 68, 212, 0.12);
    box-shadow: 0 10px 36px rgba(99, 68, 212, 0.08);
}

.site-card:hover {
    transform: translateY(-3px);
}

.site-card h3 {
    margin: 0 0 10px;
    font-size: 17px;
    font-weight: 700;
}

.site-card p {
    margin: 0;
    font-size: 14px;
    line-height: 1.65;
    opacity: 0.88;
}

.site-footer-note {
    margin-top: 48px;
    text-align: center;
    font-size: 13px;
    opacity: 0.65;
}

.site-footer-note a {
    color: inherit;
    text-decoration: underline;
    text-underline-offset: 3px;
}

/* ========== 登录页：顶栏下内容区 ========== */
body.site-auth .auth-wrap {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: calc(var(--si-topbar-h) + env(safe-area-inset-top, 0px) + 24px) max(20px, env(safe-area-inset-right, 0px)) 32px max(20px, env(safe-area-inset-left, 0px));
    position: relative;
    z-index: 2;
}

body.site-auth.theme-dark {
    background: #030312;
    color: #e2e8f0;
}

body.site-auth.theme-light {
    background: linear-gradient(180deg, #f5f3ff 0%, #eef2ff 100%);
    color: #1a1528;
}

/* 避免 theme.js 里 body.theme-light a 全局规则把主按钮文字改成紫色 */
a.site-btn--primary,
a.site-btn--primary:visited {
    color: #fff !important;
}