:root{
  --bg:#ffffff; --line:#e6e8eb; --text:#0f1720; --muted:#64738b;
  --blue:#1a73e8; --brand:#00ff84; --brandText:#001b0f;
  --card:#ffffff; --shadow:0 8px 24px rgba(16,24,40,.06);
}
*{box-sizing:border-box} html,body{margin:0}
body{background:var(--bg);color:var(--text);font:15px/1.45 system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif}
img,svg{max-width:100%;height:auto}

/* INTRO */
.intro{position:fixed;inset:0;background:#0b0f12;color:#eaf7f3;display:flex;align-items:center;justify-content:center;z-index:1000}
.intro.hide{animation:introFade .28s ease forwards}
@keyframes introFade{to{opacity:0;visibility:hidden}}
.intro__card{width:min(560px,92vw);padding:20px;text-align:center}
.intro__logo{width:84px;margin-bottom:10px}
.intro__title{margin:6px 0 4px}
.intro__lead{margin:0 0 8px;color:#9fb3bd}
.intro__list{list-style:none;padding:0;margin:12px 0 14px;text-align:left}
.intro__list li{margin:6px 0}
.intro__start{background:var(--brand);color:var(--brandText);border:1px solid var(--brand)}
.intro__skip{display:block;margin:10px auto 0}

/* header */
.bar{position:sticky;top:0;z-index:10;background:#fff;border-bottom:1px solid var(--line);
     display:flex;align-items:center;justify-content:space-between;padding:10px 14px}
.brand{display:flex;align-items:center;gap:8px;font-weight:800}
.logo{height:22px;width:auto;display:block}
.ic{appearance:none;border:1px solid var(--line);background:#f3f4f6;border-radius:10px;padding:6px 10px;font-weight:700}

/* tabs */
.tabs{position:sticky;top:48px;z-index:9;display:flex;gap:10px;padding:8px 14px;border-bottom:1px solid var(--line);background:#fff}
.tab{padding:8px 12px;border-radius:999px;border:1px solid var(--line);background:#f8fafc;font-weight:600}
.tab.active{background:#e8f0fe;border-color:#c7dafc;color:var(--blue)}

/* frame like Gmail */
.frame{max-width:860px;margin:10px auto 90px;background:#fff;box-shadow:var(--shadow);border-radius:14px;border:1px solid var(--line);overflow:hidden}
.box{display:none}.box.active{display:block}

/* rows */
.row{display:flex;gap:12px;padding:14px 16px;border-bottom:1px solid #eef2f7;background:#fff}
.row:last-child{border-bottom:0}
.unread .from,.unread .subj{font-weight:800}
.avatar{flex:0 0 36px;height:36px;border-radius:999px;display:grid;place-items:center;font-weight:800}
.avatar.in{background:#dff5e3;color:#0b6e2b}
.avatar.ex{background:#e8f2ff;color:#185ea5}
.avatar.toad{background:#e9fff6;color:#0b6e2b}
.col{min-width:0;flex:1}
.top{display:flex;justify-content:space-between;align-items:center}
.from{font-size:13px;color:#374151}
.time{font-size:12px;color:#9aa3ae}
.subj{margin:4px 0 2px;font-size:16px}
.prev{margin:0;color:#6b7280}
.chip{display:inline-block;margin-top:6px;padding:2px 8px;border:1px solid #00ff84;color:#00ff84;border-radius:999px;font-size:12px}

/* CTA */
.fab{position:fixed;right:16px;bottom:18px;z-index:20;height:48px;padding:0 18px;border-radius:999px;
  background:var(--brand);color:var(--brandText);border:1px solid var(--brand);text-decoration:none;font-weight:800;
  display:inline-flex;align-items:center;justify-content:center;box-shadow:0 10px 28px rgba(0,0,0,.22)}

/* overlay sheet */
.overlay{position:fixed;inset:0;background:rgba(0,0,0,.3);display:none;align-items:center;justify-content:center;z-index:30}
.overlay.show{display:flex}
.sheet{width:min(960px,96vw);max-height:92vh;background:#fff;border:1px solid var(--line);border-radius:14px;box-shadow:0 16px 60px rgba(0,0,0,.25);display:flex;flex-direction:column;overflow:hidden}
.sheet-head{display:flex;align-items:center;gap:10px;padding:10px 14px;border-bottom:1px solid var(--line)}
.title{font-weight:800;font-size:16px}
.sheet-grid{display:grid;grid-template-columns:1fr;gap:12px;padding:12px}
@media (min-width: 900px){ .sheet-grid{grid-template-columns:1.25fr .85fr} }

/* message card styles */
.card{border:1px solid var(--line);border-radius:12px;overflow:hidden;background:#fff}
.head{display:flex;align-items:center;gap:8px;padding:12px;border-bottom:1px solid var(--line)}
.head.ms{background:#f6f8fb}.head.od{background:#f5f9ff}.head.toad{background:#0b0f12;color:#eaf7f3;border-bottom-color:#1f2933}
.body{padding:12px}
.btn{appearance:none;border-radius:8px;padding:10px 14px;font-weight:800;text-decoration:none;cursor:pointer}
.primary{background:#0067b8;color:#fff;border:1px solid #0067b8}
.ghost{background:#fff;border:1px solid var(--line);color:#111}

/* impact */
.impact{border:1px solid var(--line);border-radius:12px;padding:12px;height:max-content;background:#fff}
.impact h4{margin:0 0 8px}
.facts{list-style:none;margin:0 0 12px;padding:0}
.facts li{margin:4px 0}
.note{font-size:12px;color:#6b7280}

/* login modal */
.modal{position:fixed;inset:0;display:none;align-items:center;justify-content:center;background:rgba(0,0,0,.45);z-index:40}
.modal.show{display:flex}
.panel{width:min(420px,92vw);background:#fff;border:1px solid var(--line);border-radius:14px;box-shadow:0 12px 44px rgba(0,0,0,.35);padding:16px;position:relative}
.panel-dark{width:min(720px,92vw);color:#eaf7f3;background:#0b0f12;border-color:#1f2933}
.ic.x{position:absolute;right:10px;top:10px}
.m-logo{width:110px;margin-bottom:6px}
.m-title{font-size:20px;margin:4px 0 10px}
.lbl{display:block;font-size:13px;margin:10px 0 4px}
.in{width:100%;padding:11px;border:1px solid var(--line);border-radius:8px}
.row{margin-top:12px;display:flex;justify-content:space-between;align-items:center}
.link{color:#106ebe;text-decoration:none}
.cap{margin-top:12px;border:1px solid var(--line);border-radius:10px;padding:8px 10px}
pre{white-space:pre-wrap;background:#f8fafc;border:1px dashed #e5e7eb;border-radius:8px;padding:8px;margin:8px 0 0}
.notice{margin-top:12px;background:#fff3cd;border:1px solid #f0c36a;border-radius:10px;padding:10px}

/* how-to */
.how{padding-left:18px}
.how li{margin:8px 0}