/* ============================================================
   WebMail —— 三栏网页邮箱
   布局：左侧导航 / 邮件列表 / 正文阅读区
   断点：>1023 三栏 ｜ 768–1023 列表+正文（导航转抽屉）｜ <768 单栏
   ============================================================ */

:root{
    --bg:#f7f9fc;
    --nav-bg:#f7f9fc;
    --surface:#ffffff;
    --surface-2:#f1f3f4;
    --surface-3:#e4e7eb;
    --text:#1f2328;
    --text-2:#444a51;
    --text-muted:#6b7280;
    --border:#e6e9ee;
    --border-2:#d7dce3;
    --accent:#1a73e8;
    --accent-hover:#1666cf;
    --accent-soft:#d9e6fd;
    --accent-soft-2:#eaf1fd;
    --danger:#d93025;
    --success:#188038;
    --shadow-1:0 1px 2px rgba(16,24,40,.06), 0 1px 3px rgba(16,24,40,.05);
    --shadow-2:0 4px 10px rgba(16,24,40,.10), 0 12px 28px rgba(16,24,40,.10);
    --radius:12px;
    --topbar-h:62px;
    --nav-w:230px;
    --nav-w-mini:76px;
    --list-w:392px;
}

@media (prefers-color-scheme: dark){
    :root{
        --bg:#191a1d;
        --nav-bg:#1d1e22;
        --surface:#24262b;
        --surface-2:#2e3036;
        --surface-3:#3a3d44;
        --text:#e8eaed;
        --text-2:#c4c8ce;
        --text-muted:#9aa0a6;
        --border:#33363c;
        --border-2:#42464e;
        --accent:#8ab4f8;
        --accent-hover:#a6c8ff;
        --accent-soft:#2c3f5c;
        --accent-soft-2:#252f3f;
        --danger:#f28b82;
        --success:#81c995;
        --shadow-1:0 1px 2px rgba(0,0,0,.45);
        --shadow-2:0 6px 18px rgba(0,0,0,.55);
    }
}

*{ box-sizing:border-box; margin:0; padding:0; }
html,body{ height:100%; }

body{
    font-family:system-ui,-apple-system,"Segoe UI",Roboto,"Noto Sans",
                "PingFang SC","Microsoft YaHei",sans-serif;
    font-size:14px;
    line-height:1.55;
    color:var(--text);
    background:var(--bg);
    -webkit-font-smoothing:antialiased;
    text-rendering:optimizeLegibility;
}

a{ color:var(--accent); text-decoration:none; }
button{ font-family:inherit; cursor:pointer; color:inherit; }
input,select,textarea{ font-family:inherit; }

.svg-ico{ display:block; flex:0 0 auto; }

::-webkit-scrollbar{ width:10px; height:10px; }
::-webkit-scrollbar-thumb{
    background:var(--surface-3); border-radius:8px;
    border:2px solid transparent; background-clip:content-box;
}
::-webkit-scrollbar-thumb:hover{ background:var(--text-muted); background-clip:content-box; }
::-webkit-scrollbar-track{ background:transparent; }

/* ============================================================
   骨架
   ============================================================ */
body.app{
    display:grid;
    grid-template-columns:var(--nav-w) var(--list-w) minmax(0,1fr);
    grid-template-rows:var(--topbar-h) minmax(0,1fr);
    grid-template-areas:
        "top  top  top"
        "nav  list read";
    height:100vh;
    height:100dvh;
    overflow:hidden;
    background:var(--bg);
    transition:grid-template-columns .22s cubic-bezier(.2,.8,.3,1);
}

/* ---------- 桌面端：☰ 折叠成图标栏 ---------- */
@media (min-width:1024px){
    body.app.nav-collapsed{
        grid-template-columns:var(--nav-w-mini) var(--list-w) minmax(0,1fr);
    }
    body.app.nav-collapsed .sidenav{
        padding:14px 10px 20px;
        overflow:visible;
    }
    body.app.nav-collapsed .compose-btn{
        width:48px; height:48px;
        margin:0 auto 18px;
        padding:0;
        justify-content:center;
        border-radius:50%;
    }
    body.app.nav-collapsed .compose-btn > span{ display:none; }
    body.app.nav-collapsed .nav-title{ display:none; }
    body.app.nav-collapsed .nav-sep{ margin:12px 8px; }
    body.app.nav-collapsed .nav-item,
    body.app.nav-collapsed .nav-item.small{
        width:46px; height:46px;
        margin:0 auto 2px;
        padding:0;
        gap:0;
        justify-content:center;
        border-radius:50%;
        /* 基础样式里是 overflow:hidden，会裁掉悬停气泡，这里必须放开 */
        overflow:visible;
    }
    body.app.nav-collapsed .nav-item .label{ display:none; }
    body.app.nav-collapsed .nav-item .avatar{ margin:0; }
    /* 折叠时把文字做成浮出的提示气泡 */
    body.app.nav-collapsed .nav-item::after{
        content:attr(data-tip);
        position:absolute;
        left:calc(100% + 10px);
        top:50%;
        transform:translateY(-50%) scale(.96);
        padding:6px 11px;
        border-radius:8px;
        background:var(--text);
        color:var(--surface);
        font-size:12.5px;
        font-weight:500;
        white-space:nowrap;
        opacity:0;
        pointer-events:none;
        transition:opacity .14s ease, transform .14s ease;
        z-index:60;
        box-shadow:var(--shadow-2);
    }
    body.app.nav-collapsed .nav-item:hover::after{
        opacity:1;
        transform:translateY(-50%) scale(1);
    }
    body.app.nav-collapsed .nav-item{ position:relative; }
}

/* ---------- 顶栏 ---------- */
.topbar{
    grid-area:top;
    display:flex;
    align-items:center;
    gap:10px;
    padding:0 14px 0 10px;
    background:var(--surface);
    border-bottom:1px solid var(--border);
    z-index:30;
}
.icon-btn{
    width:40px; height:40px;
    display:inline-flex; align-items:center; justify-content:center;
    border:none; border-radius:50%;
    background:transparent; color:var(--text-2);
    transition:background .15s ease, color .15s ease;
    flex:0 0 auto;
}
.icon-btn:hover{ background:var(--surface-2); color:var(--text); }

.brand{
    display:flex; align-items:center; gap:9px;
    font-size:19px; font-weight:650; letter-spacing:-.2px;
    color:var(--text); white-space:nowrap;
}
.brand .logo{
    width:30px; height:30px; border-radius:9px;
    background:linear-gradient(135deg,#1a73e8 0%,#4aa3f0 55%,#5ec8f5 100%);
    display:inline-flex; align-items:center; justify-content:center;
    color:#fff; font-size:15px; font-weight:800;
    box-shadow:0 2px 6px rgba(26,115,232,.35);
}
.topbar .spacer{ flex:1; }

.account-chip{
    display:inline-flex; align-items:center; gap:9px;
    padding:5px 14px 5px 6px;
    border:1px solid var(--border);
    border-radius:999px;
    background:var(--surface);
    color:var(--text);
    font-size:13px;
    max-width:300px;
    transition:background .15s ease, border-color .15s ease;
}
.account-chip:hover{ background:var(--surface-2); border-color:var(--border-2); text-decoration:none; }
.account-chip .who{
    overflow:hidden; text-overflow:ellipsis; white-space:nowrap;
    font-weight:500;
}

/* 头像 */
.avatar{
    width:32px; height:32px; border-radius:50%;
    display:inline-flex; align-items:center; justify-content:center;
    color:#fff; font-size:13px; font-weight:650;
    flex:0 0 auto; text-transform:uppercase;
    letter-spacing:.2px;
}
.avatar.lg{ width:44px; height:44px; font-size:17px; }
.avatar.sm{ width:24px; height:24px; font-size:11px; }

/* ---------- 左侧导航 ---------- */
.sidenav{
    grid-area:nav;
    display:flex; flex-direction:column;
    background:var(--nav-bg);
    border-right:1px solid var(--border);
    padding:14px 0 20px;
    overflow-y:auto;
    overflow-x:hidden;
    z-index:40;
}

.compose-btn{
    display:flex; align-items:center; gap:12px;
    margin:0 14px 16px;
    padding:0 20px;
    height:48px;
    border:none; border-radius:999px;
    background:var(--accent-soft);
    color:var(--text);
    font-size:14px; font-weight:650;
    box-shadow:var(--shadow-1);
    transition:box-shadow .18s ease, transform .18s ease, background .18s ease;
    flex:0 0 auto;
}
.compose-btn:hover{
    box-shadow:var(--shadow-2);
    transform:translateY(-1px);
    background:var(--accent-soft-2);
}
.compose-btn .svg-ico{ color:var(--accent); }

.nav-item{
    display:flex; align-items:center; gap:16px;
    height:38px;
    padding:0 16px;
    margin:0 8px 1px 0;
    border-radius:0 999px 999px 0;
    color:var(--text-2);
    font-size:14px;
    white-space:nowrap;
    overflow:hidden;
    transition:background .14s ease, color .14s ease;
}
.nav-item .svg-ico{ color:var(--text-muted); transition:color .14s ease; }
.nav-item .label{
    flex:1; min-width:0;
    overflow:hidden; text-overflow:ellipsis; white-space:nowrap;
}
.nav-item:hover{ background:var(--surface-2); color:var(--text); text-decoration:none; }
.nav-item:hover .svg-ico{ color:var(--text-2); }
.nav-item.active{
    background:var(--accent-soft);
    color:var(--accent);
    font-weight:650;
}
.nav-item.active .svg-ico{ color:var(--accent); }

.nav-sep{ height:1px; background:var(--border); margin:12px 20px 12px 16px; flex:0 0 auto; }
.nav-title{
    padding:0 16px 7px;
    font-size:11.5px; font-weight:650;
    letter-spacing:.5px; text-transform:uppercase;
    color:var(--text-muted);
    flex:0 0 auto;
}
.nav-item.small{ height:36px; font-size:13.5px; gap:12px; }
.nav-item.small .avatar{ margin-left:1px; }

/* ---------- 列表栏 ---------- */
.list-col{
    grid-area:list;
    display:flex; flex-direction:column;
    min-width:0;
    background:var(--surface);
    border-right:1px solid var(--border);
    overflow:hidden;
}
.list-head{
    padding:16px 16px 12px;
    border-bottom:1px solid var(--border);
    flex:0 0 auto;
}
.list-head .row1{
    display:flex; align-items:center; gap:10px; margin-bottom:12px;
}
.list-head h1{
    font-size:17px; font-weight:650; letter-spacing:-.2px;
    flex:1; min-width:0;
    overflow:hidden; text-overflow:ellipsis; white-space:nowrap;
}
.count-pill{
    font-size:11.5px; font-weight:600;
    color:var(--text-muted);
    background:var(--surface-2);
    padding:3px 10px; border-radius:999px;
    white-space:nowrap; flex:0 0 auto;
}
.filter-wrap{ position:relative; }
.filter-wrap .svg-ico{
    position:absolute; left:12px; top:50%; transform:translateY(-50%);
    color:var(--text-muted); pointer-events:none;
}
.filter-input{
    width:100%;
    height:38px;
    padding:0 14px 0 38px;
    border:1px solid transparent;
    border-radius:999px;
    background:var(--surface-2);
    color:var(--text);
    font-size:13.5px;
    outline:none;
    transition:background .15s ease, border-color .15s ease, box-shadow .15s ease;
}
.filter-input::placeholder{ color:var(--text-muted); }
.filter-input:focus{
    background:var(--surface);
    border-color:var(--accent);
    box-shadow:0 0 0 3px var(--accent-soft-2);
}

.list-scroll{ flex:1; overflow-y:auto; overflow-x:hidden; }

.mail-row{
    display:flex; align-items:center; gap:12px;
    padding:11px 16px 11px 14px;
    border-bottom:1px solid var(--border);
    border-radius:0 10px 10px 0;
    color:var(--text);
    cursor:pointer;
    transition:background .12s ease;
}
.mail-row:hover{ background:var(--surface-2); text-decoration:none; }
.mail-row.active{ background:var(--accent-soft); }
.mail-row.active .r-from{ color:var(--accent); }

.r-body{ flex:1; min-width:0; }
.r-line1{ display:flex; align-items:baseline; gap:10px; }
.r-from{
    font-size:14px; font-weight:600;
    overflow:hidden; text-overflow:ellipsis; white-space:nowrap;
    flex:1; min-width:0;
}
.r-date{
    font-size:12px; color:var(--text-muted);
    flex:0 0 auto; font-variant-numeric:tabular-nums;
}
.r-subject{
    display:block;
    font-size:13px; margin-top:2px;
    color:var(--text-2);
    overflow:hidden; text-overflow:ellipsis; white-space:nowrap;
}
.r-subject .no-subj{ color:var(--text-muted); font-style:italic; }

/* ---------- 阅读区 ---------- */
.read-col{
    grid-area:read;
    display:flex; flex-direction:column;
    min-width:0;
    background:var(--surface);
    overflow:hidden;
}
.read-toolbar{
    display:flex; align-items:center; gap:8px;
    padding:11px 16px;
    border-bottom:1px solid var(--border);
    flex:0 0 auto;
    background:var(--surface);
}
.tool-btn{
    display:inline-flex; align-items:center; gap:7px;
    height:36px; padding:0 15px;
    border:1px solid var(--border-2);
    border-radius:999px;
    background:var(--surface);
    color:var(--text-2);
    font-size:13px; font-weight:550;
    transition:background .15s ease, border-color .15s ease, color .15s ease;
}
.tool-btn:hover{ background:var(--surface-2); color:var(--text); text-decoration:none; }
.tool-btn.primary{
    background:var(--accent); border-color:var(--accent); color:#fff;
}
.tool-btn.primary:hover{ background:var(--accent-hover); border-color:var(--accent-hover); color:#fff; }
@media (prefers-color-scheme: dark){
    .tool-btn.primary{ color:#15181d; font-weight:650; }
}

.read-scroll{ flex:1; overflow-y:auto; }
.read-inner{
    max-width:840px;
    padding:28px 32px 72px;
}
.read-subject{
    font-size:23px; font-weight:650; line-height:1.38;
    letter-spacing:-.3px;
    margin-bottom:22px;
    word-break:break-word;
}
.read-meta{
    display:flex; align-items:flex-start; gap:14px;
    padding-bottom:20px;
    border-bottom:1px solid var(--border);
    margin-bottom:26px;
}
.read-meta .who{ flex:1; min-width:0; }
.read-meta .name{
    font-weight:650; font-size:15px; word-break:break-word;
}
.read-meta .addr{
    color:var(--text-muted); font-size:12.5px;
    word-break:break-all; margin-top:2px;
}
.read-meta .time{
    color:var(--text-muted); font-size:12.5px;
    white-space:nowrap; flex:0 0 auto; padding-top:2px;
    font-variant-numeric:tabular-nums;
}

.mail-body{ word-break:break-word; line-height:1.75; font-size:14.5px; color:var(--text); }
.mail-body p{ margin-bottom:12px; }
.mail-body img{ max-width:100%; height:auto; border-radius:8px; }
.mail-body table{ max-width:100%; border-collapse:collapse; }
.mail-body a{ text-decoration:underline; text-underline-offset:2px; }
.plain-body{ white-space:pre-wrap; font-family:inherit; font-size:14px; }

/* 附件 */
.attach-list{
    margin-top:26px; padding-top:20px;
    border-top:1px solid var(--border);
}
.attach-list .t{
    display:flex; align-items:center; gap:7px;
    font-size:12.5px; font-weight:650;
    color:var(--text-muted);
    margin-bottom:12px;
}
.attach-item{
    display:inline-flex; align-items:center; gap:10px;
    height:42px; padding:0 8px 0 14px;
    margin:0 9px 9px 0;
    border:1px solid var(--border-2);
    border-radius:10px;
    background:var(--surface-2);
    font-size:13px;
    max-width:100%;
    transition:border-color .15s ease, background .15s ease;
}
.attach-item:hover{ border-color:var(--accent); background:var(--surface); }
.attach-item .nm{
    overflow:hidden; text-overflow:ellipsis; white-space:nowrap;
    max-width:220px; font-weight:500;
}
.attach-item .sz{
    color:var(--text-muted); font-size:11.5px;
    flex:0 0 auto; font-variant-numeric:tabular-nums;
}
.attach-item .act{
    display:inline-flex; align-items:center; justify-content:center;
    width:28px; height:28px; border-radius:7px;
    color:var(--text-muted);
    transition:background .14s ease, color .14s ease;
}
.attach-item .act:hover{ background:var(--accent-soft); color:var(--accent); }

/* 回复框 */
.reply-box{
    margin-top:30px; padding-top:24px;
    border-top:1px solid var(--border);
}
.reply-box h3{
    display:flex; align-items:center; gap:8px;
    font-size:14.5px; font-weight:650; margin-bottom:14px;
}
.reply-box input,
.reply-box textarea{
    width:100%;
    padding:12px 15px;
    margin-bottom:12px;
    border:1px solid var(--border-2);
    border-radius:11px;
    background:var(--surface-2);
    color:var(--text);
    font-size:14px;
    outline:none;
    transition:background .15s ease, border-color .15s ease, box-shadow .15s ease;
}
.reply-box textarea{ min-height:140px; resize:vertical; line-height:1.65; }
.reply-box input:focus,
.reply-box textarea:focus{
    background:var(--surface);
    border-color:var(--accent);
    box-shadow:0 0 0 3px var(--accent-soft-2);
}
.reply-box .actions{ display:flex; gap:10px; align-items:center; margin-top:4px; }

.btn-send{
    display:inline-flex; align-items:center; gap:8px;
    height:40px; padding:0 26px;
    border:none; border-radius:999px;
    background:var(--accent); color:#fff;
    font-size:14px; font-weight:650;
    transition:background .15s ease, box-shadow .15s ease;
}
.btn-send:hover{ background:var(--accent-hover); box-shadow:var(--shadow-2); }
@media (prefers-color-scheme: dark){
    .btn-send{ color:#15181d; }
}
.btn-ghost{
    height:40px; padding:0 20px;
    border:1px solid var(--border-2); border-radius:999px;
    background:transparent; color:var(--text-2);
    font-size:14px; font-weight:550;
    transition:background .15s ease;
}
.btn-ghost:hover{ background:var(--surface-2); }

/* 空状态 */
.empty{
    flex:1;
    display:flex; flex-direction:column;
    align-items:center; justify-content:center;
    gap:6px;
    padding:64px 32px;
    text-align:center;
    color:var(--text-muted);
}
.empty .glyph{
    width:76px; height:76px; border-radius:50%;
    display:flex; align-items:center; justify-content:center;
    background:var(--surface-2);
    color:var(--text-muted);
    margin-bottom:12px;
}
.empty h3{ font-size:15.5px; font-weight:650; color:var(--text); }
.empty p{ font-size:13.5px; max-width:360px; line-height:1.7; }
.empty .btn{ margin-top:14px; }

/* 错误横幅 */
.banner{
    display:flex; align-items:flex-start; gap:9px;
    margin:12px 14px 0;
    padding:11px 14px;
    border-radius:10px;
    font-size:12.5px;
    line-height:1.6;
    background:color-mix(in srgb, var(--danger) 11%, transparent);
    color:var(--danger);
    word-break:break-word;
    flex:0 0 auto;
}
.banner .svg-ico{ margin-top:1px; }

/* 顶部提示浮层 */
.toast-wrap{
    position:fixed;
    top:calc(var(--topbar-h) + 14px);
    left:50%;
    transform:translateX(-50%);
    z-index:200;
    display:flex; flex-direction:column; gap:8px; align-items:center;
    max-width:min(560px, calc(100vw - 32px));
    pointer-events:none;
}
.flash{
    display:flex; align-items:center; gap:9px;
    padding:12px 18px;
    border-radius:11px;
    font-size:13.5px;
    line-height:1.6;
    word-break:break-word;
    background:var(--surface);
    border:1px solid var(--border);
    box-shadow:var(--shadow-2);
    pointer-events:auto;
    animation:toast-in .22s cubic-bezier(.2,.8,.3,1);
}
@keyframes toast-in{
    from{ opacity:0; transform:translateY(-8px) scale(.98); }
    to{ opacity:1; transform:translateY(0) scale(1); }
}
.flash.err{ background:var(--surface); color:var(--danger); border-color:color-mix(in srgb, var(--danger) 40%, transparent); }
.flash.ok{ background:var(--surface); color:var(--success); border-color:color-mix(in srgb, var(--success) 40%, transparent); }

.span-all{
    grid-column:2 / -1;
    grid-row:2 / -1;
    display:flex;
    min-height:0;
    background:var(--surface);
}

/* 窄屏底部标签栏：默认不显示 */
.tabbar{ display:none; }

/* ============================================================
   表单页
   ============================================================ */
.page{
    grid-column:2 / -1;
    grid-row:2 / -1;
    overflow-y:auto;
    padding:32px 32px 72px;
    background:var(--bg);
}
.form-card{
    max-width:720px;
    margin:0 auto;
    background:var(--surface);
    border:1px solid var(--border);
    border-radius:16px;
    box-shadow:var(--shadow-1);
    padding:30px 34px 34px;
}
.form-card h2{
    font-size:19px; font-weight:650; letter-spacing:-.2px; margin-bottom:6px;
}
.form-card .sub{
    color:var(--text-muted); font-size:13px; margin-bottom:26px; line-height:1.65;
}
.form-item{ margin-bottom:18px; }
label{ display:block; margin-bottom:7px; font-size:12.5px; font-weight:650; color:var(--text-2); }
input[type=text],input[type=email],input[type=password],input[type=number],select,textarea{
    width:100%;
    padding:11px 14px;
    border:1px solid var(--border-2);
    border-radius:10px;
    background:var(--surface-2);
    color:var(--text);
    font-size:14px;
    outline:none;
    transition:background .15s ease, border-color .15s ease, box-shadow .15s ease;
}
input:focus,select:focus,textarea:focus{
    background:var(--surface);
    border-color:var(--accent);
    box-shadow:0 0 0 3px var(--accent-soft-2);
}
input[type=checkbox]{ width:auto; accent-color:var(--accent); }
textarea{ resize:vertical; line-height:1.65; }
fieldset{
    border:1px solid var(--border);
    border-radius:13px;
    padding:18px 20px 20px;
    margin:22px 0;
}
legend{
    padding:0 9px; font-size:11.5px; font-weight:650;
    color:var(--text-muted); text-transform:uppercase; letter-spacing:.5px;
}
.form-actions{ display:flex; gap:12px; align-items:center; margin-top:10px; flex-wrap:wrap; }
.btn{
    display:inline-flex; align-items:center; justify-content:center; gap:8px;
    height:42px; padding:0 24px;
    border:none; border-radius:999px;
    background:var(--accent); color:#fff;
    font-size:14px; font-weight:650;
    transition:background .15s ease, box-shadow .15s ease;
}
.btn:hover{ background:var(--accent-hover); box-shadow:var(--shadow-2); text-decoration:none; }
@media (prefers-color-scheme: dark){ .btn{ color:#15181d; } }
.btn-block{ width:100%; }
.btn-line{
    display:inline-flex; align-items:center; justify-content:center; gap:8px;
    height:42px; padding:0 22px;
    border:1px solid var(--border-2); border-radius:999px;
    background:transparent; color:var(--text-2);
    font-size:14px; font-weight:600;
    transition:background .15s ease;
}
.btn-line:hover{ background:var(--surface-2); text-decoration:none; color:var(--text); }
.hint-line{ font-size:12.5px; color:var(--text-muted); margin-top:7px; line-height:1.65; }

/* ---------- 登录 / 注册 ---------- */
body.auth{
    display:flex; align-items:center; justify-content:center;
    min-height:100vh; min-height:100dvh;
    padding:24px;
    background:
        radial-gradient(900px 460px at 50% -12%, var(--accent-soft-2), transparent 68%),
        var(--bg);
}
.auth-card{
    width:100%; max-width:424px;
    background:var(--surface);
    border:1px solid var(--border);
    border-radius:18px;
    box-shadow:var(--shadow-2);
    padding:36px 34px 30px;
}
.auth-card .brand{ justify-content:center; margin-bottom:6px; font-size:20px; }
.auth-card h2{
    font-size:17px; font-weight:600; text-align:center;
    color:var(--text-muted); margin-bottom:26px;
}
.auth-foot{
    margin-top:22px; text-align:center;
    font-size:13px; color:var(--text-muted);
}

/* ---------- 落地页 ---------- */
body.landing{ background:var(--bg); }
.hero{
    padding:96px 24px 76px;
    text-align:center;
    background:radial-gradient(900px 440px at 50% -18%, var(--accent-soft-2), transparent 66%);
}
.hero .brand{ justify-content:center; font-size:38px; margin-bottom:20px; gap:12px; }
.hero .brand .logo{ width:52px; height:52px; font-size:26px; border-radius:14px; }
.hero p{
    max-width:600px; margin:0 auto 34px;
    font-size:16px; line-height:1.85; color:var(--text-muted);
}
.hero .cta{ display:flex; gap:14px; justify-content:center; flex-wrap:wrap; }
.section{
    max-width:1000px; margin:0 auto; padding:52px 24px;
    border-top:1px solid var(--border);
}
.section h2{
    font-size:19px; font-weight:650; letter-spacing:-.2px; margin-bottom:20px;
}
.section p{ font-size:14.5px; line-height:1.9; color:var(--text-muted); margin-bottom:12px; }
.features{
    display:grid;
    grid-template-columns:repeat(auto-fit,minmax(272px,1fr));
    gap:16px;
    margin-top:24px;
}
.feature{
    background:var(--surface);
    border:1px solid var(--border);
    border-radius:14px;
    padding:22px 24px;
    box-shadow:var(--shadow-1);
    transition:box-shadow .2s ease, transform .2s ease, border-color .2s ease;
}
.feature:hover{ box-shadow:var(--shadow-2); transform:translateY(-2px); border-color:var(--border-2); }
.feature .glyph{
    width:40px; height:40px; border-radius:11px;
    display:flex; align-items:center; justify-content:center;
    background:var(--accent-soft-2); color:var(--accent);
    margin-bottom:14px;
}
.feature h3{ font-size:14.5px; font-weight:650; margin-bottom:8px; }
.feature p{ font-size:13.5px; margin:0; line-height:1.75; }
footer.site{
    padding:44px 24px 64px; text-align:center;
    font-size:13px; color:var(--text-muted);
}

/* ============================================================
   响应式
   ============================================================ */

/* 中等宽度：导航收进抽屉，列表与正文并排 */
@media (max-width:1023px){
    body.app{
        grid-template-columns:var(--list-w) minmax(0,1fr);
        grid-template-areas:
            "top  top"
            "list read";
    }
    .sidenav{
        position:fixed;
        top:var(--topbar-h); bottom:0; left:0;
        width:272px;
        background:var(--surface);
        border-right:1px solid var(--border);
        box-shadow:var(--shadow-2);
        transform:translateX(-102%);
        transition:transform .22s cubic-bezier(.2,.8,.3,1);
        z-index:45;
    }
    body.app.nav-open .sidenav{ transform:none; }
    body.app.nav-open::after{
        content:"";
        position:fixed; inset:var(--topbar-h) 0 0 0;
        background:rgba(15,20,28,.38);
        z-index:44;
    }
    .page, .span-all{ grid-column:1 / -1; }
    .read-inner{ padding:24px 26px 64px; }
}

/* 窄屏：单栏，列表与正文互斥，底部加标签栏 */
@media (max-width:767px){
    :root{ --topbar-h:56px; --list-w:100%; }
    body.app{
        grid-template-columns:minmax(0,1fr);
        grid-template-rows:var(--topbar-h) minmax(0,1fr) 58px;
        grid-template-areas:
            "top"
            "list"
            "tab";
    }
    .read-col{ display:none; }
    body.app.reading-open .list-col{ display:none; }
    body.app.reading-open .read-col{
        display:flex;
        grid-area:list;
        border-right:none;
    }
    body.app.reading-open .back-btn{ display:inline-flex !important; }

    .tabbar{
        grid-area:tab;
        display:flex;
        background:var(--surface);
        border-top:1px solid var(--border);
        z-index:35;
    }
    .tab{
        flex:1;
        display:flex; flex-direction:column;
        align-items:center; justify-content:center;
        gap:3px;
        color:var(--text-muted);
        font-size:11px; font-weight:550;
        text-decoration:none;
        transition:color .14s ease, background .14s ease;
    }
    .tab:active{ background:var(--surface-2); }
    .tab.active{ color:var(--accent); font-weight:650; }

    .page, .span-all{ grid-row:2 / 3; }
    .account-chip{ padding:4px; border-color:transparent; }
    .account-chip .who{ display:none; }
    .brand{ font-size:17px; }
    .read-inner{ padding:18px 16px 60px; }
    .read-subject{ font-size:19px; }
    .read-toolbar{ padding:9px 12px; }
    .tool-btn{ padding:0 12px; font-size:12.5px; }
    .page{ padding:16px 14px 64px; }
    .form-card{ padding:22px 18px 26px; border-radius:13px; }
    .hero{ padding:64px 20px 52px; }
    .hero .brand{ font-size:27px; }
    .hero .brand .logo{ width:42px; height:42px; font-size:21px; }
}

/* 返回按钮只在「列表与正文互斥」的窄屏出现 */
.back-btn{ display:none !important; }
@media (max-width:767px){
    body.app.reading-open .back-btn{ display:inline-flex !important; }
}