:root{
  --bg:#0c1422; --bg2:#0f1b2d; --panel:#142036; --panel2:#1a2942; --line:#24344f;
  --text:#e8eef7; --muted:#8ba0bd; --muted2:#67788f;
  --primary:#ff5a5f; --primary2:#ff8a5b; --accent:#3da9fc; --teal:#2dd4bf;
  --ok:#34d399; --warn:#fbbf24; --danger:#f87171;
  --radius:14px; --shadow:0 10px 30px rgba(0,0,0,.35);
}
*{box-sizing:border-box}
html,body{margin:0;padding:0;height:100%}
body{
  font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;
  background:radial-gradient(1200px 600px at 80% -10%,#16243c 0,var(--bg) 55%) fixed,var(--bg);
  color:var(--text); -webkit-font-smoothing:antialiased; line-height:1.6;
}
a{color:inherit;text-decoration:none}
button{font-family:inherit;cursor:pointer}
input,textarea,select{font-family:inherit}
::-webkit-scrollbar{width:10px;height:10px}
::-webkit-scrollbar-thumb{background:#26374f;border-radius:8px}
::-webkit-scrollbar-track{background:transparent}

/* layout */
.app-shell{display:flex;min-height:100vh}
.sidebar{width:220px;flex:0 0 220px;background:linear-gradient(180deg,#101b2e,#0c1422);border-right:1px solid var(--line);display:flex;flex-direction:column;position:sticky;top:0;height:100vh}
.brand{display:flex;align-items:center;gap:10px;padding:18px 18px 14px;font-weight:800;font-size:17px}
.brand .logo{width:30px;height:30px;border-radius:9px;background:linear-gradient(135deg,var(--primary),var(--primary2));display:flex;align-items:center;justify-content:center;color:#fff;font-size:16px}
.brand small{display:block;font-weight:500;font-size:11px;color:var(--muted2);margin-top:1px}
.nav{padding:6px 10px;overflow-y:auto;flex:1}
.nav a{display:flex;align-items:center;gap:11px;padding:10px 12px;border-radius:10px;color:var(--muted);font-size:14px;margin:2px 0;transition:.15s}
.nav a:hover{background:var(--panel);color:var(--text)}
.nav a.active{background:linear-gradient(135deg,rgba(255,90,95,.18),rgba(61,169,252,.12));color:#fff}
.nav a i{width:18px;height:18px}
.nav-sep{height:1px;background:var(--line);margin:10px 12px}
.side-foot{padding:12px;border-top:1px solid var(--line);font-size:12px;color:var(--muted2)}

.main{flex:1;display:flex;flex-direction:column;min-width:0}
.topbar{height:60px;display:flex;align-items:center;justify-content:space-between;padding:0 22px;border-bottom:1px solid var(--line);background:rgba(12,20,34,.7);backdrop-filter:blur(8px);position:sticky;top:0;z-index:5}
.topbar .page-title{font-weight:700;font-size:16px}
.topbar .right{display:flex;align-items:center;gap:14px}
.content{padding:22px;max-width:1180px;width:100%;margin:0 auto}
.content.wide{max-width:1280px}

/* buttons */
.btn{display:inline-flex;align-items:center;gap:7px;justify-content:center;border:1px solid var(--line);background:var(--panel);color:var(--text);padding:9px 15px;border-radius:10px;font-size:14px;transition:.15s}
.btn:hover{border-color:#36507080;background:var(--panel2)}
.btn:disabled{opacity:.55;cursor:not-allowed}
.btn-primary{background:linear-gradient(135deg,var(--primary),var(--primary2));border:none;color:#fff;font-weight:600;box-shadow:0 6px 18px rgba(255,90,95,.3)}
.btn-primary:hover{filter:brightness(1.06)}
.btn-outline{border-color:var(--primary);color:var(--primary);background:transparent}
.btn-ghost{background:transparent;border-color:transparent;color:var(--muted)}
.btn-ghost:hover{background:var(--panel);color:var(--text)}
.btn-danger{border-color:var(--danger);color:var(--danger);background:transparent}
.btn-sm{padding:6px 11px;font-size:13px;border-radius:9px}
.btn-block{width:100%}
.icon-btn{background:transparent;border:1px solid var(--line);border-radius:9px;width:38px;height:38px;display:inline-flex;align-items:center;justify-content:center;color:var(--muted);transition:.15s}
.icon-btn:hover{color:var(--text);background:var(--panel)}

/* cards */
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:18px}
.card-pad{padding:18px}
.grid{display:grid;gap:16px}
.grid-2{grid-template-columns:repeat(2,1fr)}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-4{grid-template-columns:repeat(4,1fr)}
@media(max-width:980px){.grid-3,.grid-4{grid-template-columns:repeat(2,1fr)}.sidebar{display:none}}
@media(max-width:680px){.grid-2,.grid-3,.grid-4{grid-template-columns:1fr}}

/* form */
.field{margin-bottom:14px}
.field>label{display:block;font-size:13px;color:var(--muted);margin-bottom:6px}
.input,.textarea,.select{width:100%;background:var(--bg2);border:1px solid var(--line);color:var(--text);border-radius:10px;padding:10px 12px;font-size:14px;outline:none;transition:.15s}
.input:focus,.textarea:focus,.select:focus{border-color:var(--accent);box-shadow:0 0 0 3px rgba(61,169,252,.15)}
.textarea{min-height:120px;resize:vertical;line-height:1.7}
.select{appearance:none;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='14' height='14' viewBox='0 0 24 24' fill='none' stroke='%238ba0bd' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");background-repeat:no-repeat;background-position:right 12px center;padding-right:34px}
.row{display:flex;gap:12px}
.row>*{flex:1}
.muted{color:var(--muted)}
.muted.small{font-size:12px}
.small{font-size:12px}
.hint{font-size:12px;color:var(--muted2)}
.spacer{flex:1}
.mb-12{margin-bottom:12px}
.flex-between{display:flex;align-items:center;justify-content:space-between;gap:10px}

/* badges */
.badge{display:inline-block;font-size:11px;padding:2px 8px;border-radius:999px;background:var(--panel2);color:var(--muted);border:1px solid var(--line)}
.badge-info{color:var(--accent);border-color:rgba(61,169,252,.3)}
.badge-teal{color:var(--teal);border-color:rgba(45,212,191,.3)}
.badge-warn{color:var(--warn);border-color:rgba(251,191,36,.3)}

/* hero / landing */
.hero{padding:60px 22px 30px;text-align:center;max-width:980px;margin:0 auto}
.hero h1{font-size:42px;font-weight:800;margin:0 0 14px;line-height:1.2;background:linear-gradient(135deg,#fff,#c7d4e6);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p{font-size:17px;color:var(--muted);margin:0 auto 26px;max-width:640px}
.hero .cta{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.feature-list{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;max-width:980px;margin:34px auto 0;padding:0 22px}
@media(max-width:780px){.feature-list{grid-template-columns:1fr}.hero h1{font-size:32px}}
.feature{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:18px}
.feature .ic{width:40px;height:40px;border-radius:11px;background:linear-gradient(135deg,rgba(255,90,95,.2),rgba(61,169,252,.15));display:flex;align-items:center;justify-content:center;color:var(--primary);margin-bottom:10px}
.feature h3{margin:0 0 6px;font-size:15px}
.feature p{margin:0;font-size:13px;color:var(--muted)}

/* studio / generator */
.gen-wrap{display:grid;grid-template-columns:380px 1fr;gap:18px;align-items:start}
@media(max-width:1000px){.gen-wrap{grid-template-columns:1fr}}
.steps{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:14px}
.step-chip{font-size:12px;padding:5px 11px;border-radius:999px;background:var(--panel);border:1px solid var(--line);color:var(--muted)}
.step-chip.active{background:linear-gradient(135deg,var(--primary),var(--primary2));color:#fff;border:none}
.step-chip.done{border-color:rgba(52,211,153,.4);color:var(--ok)}
.editor{background:var(--bg2);border:1px solid var(--line);border-radius:12px;padding:16px;min-height:120px;white-space:pre-wrap;overflow:auto;font-size:15px;line-height:1.8}
.editor:empty:before{content:attr(data-ph);color:var(--muted2)}
.preview{background:#fff;color:#1a1a1a;border-radius:12px;padding:24px 20px;min-height:200px;overflow:auto;max-height:70vh}
.preview h1,.preview h2,.preview h3{color:#1a1a1a}
.preview p{color:#333;line-height:1.9}
.toolbar{display:flex;gap:8px;flex-wrap:wrap;margin-top:10px}
.kicker{font-size:12px;color:var(--muted2);text-transform:uppercase;letter-spacing:1px;margin-bottom:6px}
.title-pick{display:flex;flex-direction:column;gap:8px}
.title-opt{background:var(--bg2);border:1px solid var(--line);border-radius:10px;padding:10px 12px;font-size:14px;cursor:pointer;transition:.15s}
.title-opt:hover{border-color:var(--primary);background:var(--panel)}
.title-opt.sel{border-color:var(--primary);background:rgba(255,90,95,.1)}
.empty{text-align:center;color:var(--muted2);padding:40px 10px}
.empty i{margin-bottom:8px;color:var(--muted)}

/* chat */
.chat-box{display:flex;flex-direction:column;height:calc(100vh - 150px);max-height:760px}
.chat-log{flex:1;overflow:auto;padding:8px 4px;display:flex;flex-direction:column;gap:14px}
.msg{display:flex;gap:10px;max-width:82%}
.msg .av{width:34px;height:34px;border-radius:9px;flex:0 0 34px;display:flex;align-items:center;justify-content:center;font-size:15px;background:var(--panel2)}
.msg.ai .av{background:linear-gradient(135deg,var(--primary),var(--primary2));color:#fff}
.msg.me{margin-left:auto;flex-direction:row-reverse}
.msg.me .av{background:var(--accent);color:#fff}
.bubble{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:10px 14px;font-size:14px;line-height:1.7;white-space:pre-wrap}
.msg.me .bubble{background:rgba(61,169,252,.12);border-color:rgba(61,169,252,.3)}
.chat-input{display:flex;gap:10px;padding-top:12px;border-top:1px solid var(--line);margin-top:10px}
.chat-input .textarea{min-height:48px;flex:1}

/* article list */
.art-item{display:flex;flex-direction:column;gap:6px;background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:14px;cursor:pointer;transition:.15s}
.art-item:hover{border-color:#36507080;background:var(--panel2)}
.art-item h4{margin:0;font-size:15px}
.art-item .meta{font-size:12px;color:var(--muted2);display:flex;gap:10px;align-items:center}
.check{width:18px;height:18px;accent-color:var(--primary)}

/* hot */
.hot-item{display:flex;gap:14px;align-items:flex-start;background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:14px}
.hot-rank{font-size:18px;font-weight:800;color:var(--primary);width:28px;flex:0 0 28px}
.hot-item .body{flex:1;min-width:0}
.hot-item h4{margin:0 0 4px;font-size:15px}
.hot-item p{margin:0 0 8px;font-size:13px;color:var(--muted)}

/* modal */
.modal-mask{position:fixed;inset:0;background:rgba(5,10,18,.6);backdrop-filter:blur(3px);display:flex;align-items:center;justify-content:center;z-index:50;padding:18px}
.modal{background:var(--panel);border:1px solid var(--line);border-radius:16px;width:100%;max-width:520px;box-shadow:var(--shadow);overflow:hidden}
.modal-head{display:flex;align-items:center;justify-content:space-between;padding:16px 18px;border-bottom:1px solid var(--line)}
.modal-head h3{margin:0;font-size:16px}
.modal-body{padding:18px;max-height:70vh;overflow:auto}
.modal-foot{padding:14px 18px;border-top:1px solid var(--line);display:flex;justify-content:flex-end;gap:10px}

/* toast */
.toast{position:fixed;top:18px;left:50%;transform:translateX(-50%) translateY(-20px);background:var(--panel2);border:1px solid var(--line);color:var(--text);padding:10px 16px;border-radius:10px;display:flex;align-items:center;gap:8px;font-size:14px;box-shadow:var(--shadow);opacity:0;transition:.3s;z-index:80}
.toast.show{transform:translateX(-50%) translateY(0);opacity:1}
.toast-error{border-color:var(--danger)}
.toast-success{border-color:var(--ok)}

/* auth */
.auth-wrap{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:24px}
.auth-card{width:100%;max-width:400px;background:var(--panel);border:1px solid var(--line);border-radius:18px;padding:28px;box-shadow:var(--shadow)}
.auth-card h2{margin:0 0 4px}
.auth-card .sub{color:var(--muted);font-size:13px;margin-bottom:20px}
.auth-tabs{display:flex;gap:8px;margin-bottom:18px}
.auth-tabs button{flex:1;padding:9px;border-radius:10px;border:1px solid var(--line);background:var(--bg2);color:var(--muted)}
.auth-tabs button.active{background:var(--panel2);color:#fff;border-color:#36507080}

/* placeholder */
.placeholder{text-align:center;padding:60px 20px;color:var(--muted)}
.placeholder .ic{width:64px;height:64px;border-radius:18px;background:var(--panel2);display:inline-flex;align-items:center;justify-content:center;color:var(--muted);margin-bottom:14px}

.spinner{width:15px;height:15px;border:2px solid rgba(255,255,255,.4);border-top-color:#fff;border-radius:50%;display:inline-block;animation:spin .7s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
.tag-input{display:flex;gap:8px;flex-wrap:wrap}
.tag{background:var(--panel2);border:1px solid var(--line);border-radius:999px;padding:4px 10px;font-size:12px;color:var(--muted)}
.demo-flag{display:inline-flex;align-items:center;gap:5px;font-size:11px;color:var(--warn);background:rgba(251,191,36,.12);border:1px solid rgba(251,191,36,.3);padding:2px 8px;border-radius:999px;margin-left:8px}