/* ========== Reset & Base ========== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  --primary:#74B9FF;--primary-dim:rgba(116,185,255,.12);
  --secondary:#0984E3;--accent:#FDCB6E;--accent-dim:rgba(253,203,110,.12);
  --bg:#0A0F1A;--surface:#111827;--surface2:#1A2235;
  --border:rgba(116,185,255,.1);--text:#F1F5F9;--text-dim:#94A3B8;
  --radius:12px;--font:'Inter',system-ui,-apple-system,sans-serif;
  --transition:250ms ease;
  --easy:#2ECC71;--moderate:#F39C12;--hard:#E74C3C;--none:rgba(255,255,255,.05);
}
html{font-size:16px;scroll-behavior:smooth}
body{background:var(--bg);color:var(--text);font-family:var(--font);line-height:1.6;min-height:100vh}

/* ========== Header ========== */
.header{position:sticky;top:0;z-index:100;backdrop-filter:blur(16px);background:rgba(10,15,26,.8);border-bottom:1px solid var(--border)}
.header-inner{max-width:1100px;margin:0 auto;padding:.75rem 1.5rem;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:.75rem}
.logo{display:flex;align-items:center;gap:.5rem}
.logo-icon{font-size:1.25rem}
.logo h1{font-size:1.1rem;font-weight:700;background:linear-gradient(135deg,var(--primary),var(--accent));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.header-right{display:flex;gap:.5rem}

/* ========== Buttons ========== */
.btn{display:inline-flex;align-items:center;gap:.3rem;padding:.45rem .85rem;border:none;border-radius:8px;font-size:.8rem;font-weight:600;cursor:pointer;transition:all var(--transition);font-family:var(--font)}
.btn-primary{background:linear-gradient(135deg,var(--primary),var(--secondary));color:#fff}
.btn-primary:hover{filter:brightness(1.15);transform:translateY(-1px)}
.btn-sm{background:var(--surface2);color:var(--text-dim);border:1px solid var(--border)}
.btn-sm:hover{border-color:var(--primary);color:var(--primary)}
.btn-chip{background:var(--surface2);color:var(--text-dim);border:1px solid var(--border);font-size:.7rem;padding:.3rem .6rem;border-radius:20px}
.btn-chip:hover{border-color:var(--primary);color:var(--primary)}
.btn-remove{background:none;border:none;color:var(--text-dim);cursor:pointer;font-size:.8rem;padding:.2rem .4rem;border-radius:4px;transition:color var(--transition)}
.btn-remove:hover{color:var(--hard)}

/* ========== Main ========== */
.main{max-width:1100px;margin:0 auto;padding:1.5rem}

/* ========== Add Section ========== */
.add-section{margin-bottom:1.5rem}
.add-row{display:flex;gap:.5rem;margin-bottom:.75rem}
.add-row input{flex:1;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:.6rem 1rem;color:var(--text);font-family:var(--font);font-size:.85rem;outline:none;transition:border-color var(--transition)}
.add-row input:focus{border-color:var(--primary)}
.presets{display:flex;align-items:center;gap:.5rem;flex-wrap:wrap}
.presets-label{font-size:.75rem;color:var(--text-dim)}

/* ========== TZ List ========== */
.tz-list{display:flex;flex-wrap:wrap;gap:.5rem;margin-bottom:1.5rem}
.tz-tag{display:flex;align-items:center;gap:.5rem;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:.5rem .75rem;font-size:.8rem;transition:border-color var(--transition)}
.tz-tag:hover{border-color:var(--primary)}
.tz-tag .tz-name{font-weight:600;color:var(--primary)}
.tz-tag .tz-offset{color:var(--text-dim);font-size:.7rem}
.tz-tag .tz-time{color:var(--accent);font-weight:500}

/* ========== Section Title ========== */
.section-title{font-size:1rem;font-weight:700;margin-bottom:1rem;display:flex;align-items:center;gap:.5rem}
.section-title::before{content:'';width:4px;height:20px;background:linear-gradient(to bottom,var(--primary),var(--accent));border-radius:2px}

/* ========== Chart ========== */
.chart-section{margin-bottom:2rem}
.chart-container{display:grid;grid-template-columns:repeat(24,1fr);gap:2px;margin-bottom:1rem}
.chart-col{display:flex;flex-direction:column;align-items:center;gap:3px}
.chart-hour{font-size:.6rem;color:var(--text-dim);margin-bottom:2px}
.chart-cell{width:100%;aspect-ratio:1;border-radius:4px;transition:all var(--transition);cursor:pointer;position:relative}
.chart-cell:hover{transform:scale(1.2);z-index:10}
.chart-cell.easy{background:var(--easy)}
.chart-cell.moderate{background:var(--moderate)}
.chart-cell.hard{background:var(--hard)}
.chart-cell.none{background:var(--none)}
.legend{display:flex;gap:1.25rem;flex-wrap:wrap;font-size:.75rem;color:var(--text-dim)}
.legend-item{display:flex;align-items:center;gap:.35rem}
.legend-dot{width:12px;height:12px;border-radius:3px}
.legend-dot.easy{background:var(--easy)}.legend-dot.moderate{background:var(--moderate)}.legend-dot.hard{background:var(--hard)}.legend-dot.none{background:var(--none)}

/* ========== Windows ========== */
.window-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:1rem;margin-bottom:.75rem;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:.75rem}
.window-time{font-size:1.1rem;font-weight:700;color:var(--primary)}
.window-detail{font-size:.8rem;color:var(--text-dim)}
.window-rating{padding:.25rem .6rem;border-radius:20px;font-size:.7rem;font-weight:700}
.window-rating.easy{background:rgba(46,204,113,.15);color:var(--easy)}
.window-rating.moderate{background:rgba(243,156,18,.15);color:var(--moderate)}
.window-rating.hard{background:rgba(231,76,60,.15);color:var(--hard)}

/* ========== Converter ========== */
.converter-section{margin-top:2rem}
.converter-row{display:flex;gap:.75rem;margin-bottom:1rem;flex-wrap:wrap}
.converter-row input,.converter-row select{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:.5rem .75rem;color:var(--text);font-family:var(--font);font-size:.85rem;outline:none}
.converter-row input:focus,.converter-row select:focus{border-color:var(--primary)}
.convert-result{background:var(--surface);border:1px solid var(--border);border-radius:8px;padding:.6rem 1rem;margin-bottom:.5rem;display:flex;justify-content:space-between;align-items:center;font-size:.85rem}
.convert-result .tz-label{color:var(--text-dim)}
.convert-result .tz-converted{font-weight:600;color:var(--accent)}

/* ========== Toast ========== */
.toast{position:fixed;bottom:2rem;left:50%;transform:translateX(-50%) translateY(100px);background:var(--surface2);color:var(--text);padding:.6rem 1.25rem;border-radius:var(--radius);font-size:.8rem;font-weight:500;border:1px solid var(--primary);box-shadow:0 8px 32px rgba(0,0,0,.4);transition:transform 300ms ease;z-index:9999;pointer-events:none}
.toast.show{transform:translateX(-50%) translateY(0)}

/* ========== Responsive ========== */
@media(max-width:768px){
  .header-inner{flex-direction:column;align-items:flex-start}
  .chart-container{gap:1px}
  .chart-hour{font-size:.5rem}
}
@media(max-width:480px){
  .main{padding:1rem}
  .add-row{flex-direction:column}
}