/* AIPilot Product Base Styles — Clean UI Design System */
:root {
  --bg: #f8f9fa; --card-bg: #ffffff; --card-border: #e8e8e8;
  --primary: #2563eb; --primary-hover: #1d4ed8; --accent: #16a34a;
  --heading: #1a1a2e; --text: #333; --text-muted: #666;
  --shadow: 0 1px 3px rgba(0,0,0,.06); --shadow-lg: 0 4px 16px rgba(0,0,0,.08);
  --radius: 8px; --radius-lg: 12px;
  --font: -apple-system,"PingFang SC","Microsoft YaHei","Noto Sans SC",sans-serif;
  --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --red: #dc2626; --orange: #ea580c; --blue: #0891b2; --purple: #7c3aed;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
body{background:var(--bg);color:var(--text);font-family:var(--font);line-height:1.6;min-height:100vh}
.container{max-width:1100px;margin:0 auto;padding:0 24px}

nav{display:flex;justify-content:space-between;align-items:center;padding:20px 0;border-bottom:1px solid var(--card-border);flex-wrap:wrap;gap:12px}
.logo{font-size:20px;font-weight:700;color:var(--primary);text-decoration:none;letter-spacing:-0.5px}
.nav-links{display:flex;gap:20px;align-items:center;flex-wrap:wrap}
.nav-links a{color:var(--text-muted);text-decoration:none;font-size:14px;transition:color var(--transition)}
.nav-links a:hover{color:var(--primary)}
.lang-switch{display:flex;gap:4px;background:var(--card-bg);border:1px solid var(--card-border);border-radius:6px;padding:2px}
.lang-switch button{padding:4px 12px;border:none;background:none;font-size:12px;cursor:pointer;border-radius:4px;color:var(--text-muted);transition:all var(--transition)}
.lang-switch button.active{background:var(--primary);color:#fff}

.page-header{text-align:center;padding:40px 0 20px;animation:fadeIn .5s ease}
.page-header h1{font-size:30px;color:var(--heading);margin-bottom:8px}
.page-header .sub{color:var(--text-muted);font-size:15px;max-width:640px;margin:0 auto}
@keyframes fadeIn{from{opacity:0;transform:translateY(-12px)}to{opacity:1;transform:translateY(0)}}
@keyframes slideUp{from{opacity:0;transform:translateY(16px)}to{opacity:1;transform:translateY(0)}}

.panel{background:var(--card-bg);border:1px solid var(--card-border);border-radius:var(--radius-lg);padding:24px;box-shadow:var(--shadow);animation:slideUp .4s ease .1s both;margin-bottom:20px}
.panel h3{font-size:17px;color:var(--heading);margin-bottom:16px}

.form-group{margin-bottom:14px}
.form-group label{display:block;font-size:13px;color:var(--text-muted);margin-bottom:5px;font-weight:500}
.form-group input,.form-group select,.form-group textarea{width:100%;padding:10px 14px;background:var(--bg);border:1px solid var(--card-border);border-radius:6px;color:var(--text);font-size:14px;font-family:var(--font);outline:none;transition:border-color var(--transition),box-shadow var(--transition);resize:vertical}
.form-group input:focus,.form-group select:focus,.form-group textarea:focus{border-color:var(--primary);box-shadow:0 0 0 3px rgba(37,99,235,.1)}
.form-group textarea{min-height:60px}

.btn{display:inline-block;padding:10px 24px;border-radius:6px;font-size:14px;font-weight:600;cursor:pointer;border:none;transition:all var(--transition);font-family:var(--font);text-decoration:none}
.btn-primary{background:var(--primary);color:#fff}
.btn-primary:hover{background:var(--primary-hover);transform:translateY(-1px);box-shadow:0 4px 12px rgba(37,99,235,.25)}
.btn-accent{background:var(--accent);color:#fff}
.btn-accent:hover{filter:brightness(0.9)}
.btn-outline{background:transparent;color:var(--primary);border:1px solid var(--primary)}
.btn-outline:hover{background:#eef2ff}
.btn-sm{padding:6px 14px;font-size:12px}

.result-card{background:var(--bg);border:1px solid var(--card-border);border-radius:var(--radius);padding:16px;margin-bottom:10px;transition:all var(--transition)}
.result-card:hover{border-color:var(--primary)}

.chip{display:inline-block;padding:6px 14px;border:1px solid var(--card-border);border-radius:20px;font-size:12px;cursor:pointer;background:var(--bg);color:var(--text-muted);transition:all var(--transition);user-select:none;font-family:var(--font)}
.chip:hover{border-color:var(--primary);color:var(--primary)}
.chip.active{background:var(--primary);color:#fff;border-color:var(--primary)}

.chip-row{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:14px}

footer{border-top:1px solid var(--card-border);padding:28px 0;display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:12px;color:var(--text-muted);font-size:13px;margin-top:20px}
footer a{color:var(--text-muted);text-decoration:none;font-size:13px;transition:color var(--transition)}
footer a:hover{color:var(--primary)}

.grid-2{display:grid;grid-template-columns:1fr 1fr;gap:20px}
@media(max-width:768px){.grid-2{grid-template-columns:1fr}.page-header h1{font-size:22px}}

.cta-box{background:var(--card-bg);border:2px solid var(--primary);border-radius:var(--radius-lg);padding:32px;text-align:center;margin:32px 0;box-shadow:var(--shadow-lg)}
.cta-box h3{font-size:20px;color:var(--heading);margin-bottom:8px}
.cta-box p{color:var(--text-muted);font-size:14px;margin-bottom:16px}