/* Concept Mastery — TeachTime
 * Official Concept Mastery brand palette:
 *   CM Blue #1A5EAB (dominant) · CM Gold #E8A020 (accent) · CM Sky #EAF1FB (fill)
 *   CM Orange #D4620E · Gray Lines #D0D0D0 · Dark #1A1A1A · Mid #666 · White
 * Arial / system sans-serif, 16px base. */
*{box-sizing:border-box;margin:0;padding:0}
:root{
  --font:Arial,'Helvetica Neue',Helvetica,system-ui,-apple-system,sans-serif;
  --bg:#f6f8fc;--card:#fff;--border:#D0D0D0;--text:#1A1A1A;--muted:#666666;
  --brand:#1A5EAB;--brand-2:#12467e;--gold:#E8A020;--sky:#EAF1FB;--orange:#D4620E;
  --green:#067647;--green-bg:#ecfdf3;--red:#b42318;--red-bg:#fef3f2;
  --amber:#b54708;--amber-bg:#fdf3e0;--radius:12px;
}
html,body{min-height:100%;font-family:var(--font);background:var(--bg);color:var(--text);-webkit-font-smoothing:antialiased;line-height:1.45}
a{color:inherit;text-decoration:none}

/* top bar */
.nav{background:var(--card);border-bottom:2px solid var(--brand);padding:.7rem 1.4rem;display:flex;align-items:center;gap:1rem;flex-wrap:wrap;position:sticky;top:0;z-index:40}
.brand{display:flex;align-items:center;gap:.6rem;font-weight:700}
.brand .mark{width:34px;height:34px;border-radius:8px;background:var(--brand);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:1rem;letter-spacing:-.02em;flex:none}
.brand .txt{font-size:1.05rem;color:var(--brand);letter-spacing:-.01em;line-height:1.1}
.brand .txt small{display:block;font-size:.7rem;color:var(--muted);font-weight:600;letter-spacing:.06em;text-transform:uppercase}
.nav-right{margin-left:auto;display:flex;align-items:center;gap:.6rem;flex-wrap:wrap}
.nav-name{font-size:.82rem;color:var(--muted);font-weight:600}

/* buttons */
.btn{border:none;border-radius:8px;padding:.6rem 1.1rem;font-family:var(--font);font-size:.88rem;font-weight:700;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;gap:.4rem;transition:filter .15s,background .15s}
.btn-primary{background:var(--brand);color:#fff}
.btn-primary:hover{filter:brightness(1.1)}
.btn-ghost{background:var(--sky);color:var(--brand);border:1px solid #cddcf3}
.btn-sm{padding:.4rem .7rem;font-size:.76rem;border-radius:8px}
.btn:disabled{opacity:.55;cursor:default}
.btn-danger{background:var(--red-bg);color:var(--red);border:1px solid #fbcfc9}

/* layout */
.wrap{max-width:1080px;margin:0 auto;padding:1.5rem 1.4rem 3rem}
.wrap-lift{max-width:1080px;margin:-1.8rem auto 3rem;padding:0 1.4rem;position:relative;z-index:2}

/* hero */
.hero{background:linear-gradient(135deg,var(--brand),var(--brand-2));color:#fff;padding:2.6rem 1.4rem 3.4rem;position:relative;overflow:hidden}
.hero::after{content:"";position:absolute;left:0;right:0;bottom:0;height:5px;background:var(--gold)}
.hero-in{max-width:1080px;margin:0 auto}
.hero h1{font-size:2rem;letter-spacing:-.02em;margin-bottom:.5rem;font-weight:800}
.hero p{opacity:.92;font-size:1rem;max-width:62ch}
.hero .stats{display:flex;gap:2.2rem;margin-top:1.5rem;flex-wrap:wrap}
.hero .stat b{display:block;font-size:1.6rem;font-weight:800}
.hero .stat span{font-size:.76rem;opacity:.85;text-transform:uppercase;letter-spacing:.05em}
/* compact hero (dashboard) */
.hero-sm{padding:1.6rem 1.8rem;border-radius:16px;margin-bottom:1.4rem}
.hero-sm::after{display:none}
.hero-sm h1{font-size:1.5rem;margin-bottom:.3rem}
.hero-sm p{font-size:.9rem}

.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:1.2rem 1.3rem}
.card h2{font-size:1rem;font-weight:800;margin-bottom:.9rem;color:var(--brand);display:flex;align-items:center;gap:.45rem}

/* forms */
label{display:block;font-size:.7rem;font-weight:700;color:var(--muted);margin:.7rem 0 .3rem;text-transform:uppercase;letter-spacing:.04em}
input,select,textarea{width:100%;padding:.62rem .72rem;border:1px solid var(--border);border-radius:9px;font-family:var(--font);font-size:.92rem;background:#fff;color:var(--text)}
input:focus,select:focus,textarea:focus{outline:2px solid #bcd3f2;border-color:var(--brand)}
textarea{resize:vertical;min-height:64px}
.row2{display:grid;grid-template-columns:1fr 1fr;gap:.6rem}
.hint{font-size:.78rem;color:var(--muted);margin-top:.5rem}
.err{background:var(--red-bg);color:var(--red);border:1px solid #fbcfc9;border-radius:9px;padding:.55rem .7rem;font-size:.82rem;font-weight:600;margin-top:.7rem;display:none}
.err.show{display:block}

/* pills */
.pill{display:inline-block;font-size:.66rem;font-weight:700;padding:3px 9px;border-radius:20px;margin:2px 5px 2px 0;text-transform:uppercase;letter-spacing:.02em}
.pill-sub{background:var(--sky);color:var(--brand)}
.pill-grade{background:var(--amber-bg);color:var(--orange)}
.pill-mode{background:#eef4fd;color:var(--brand)}
.pill-open{background:#e2f6f3;color:#0f766e}
.pill-booked{background:#fdecea;color:#c0392b}

/* generic */
.empty{text-align:center;color:var(--muted);font-size:.9rem;padding:2.2rem 1rem}
.toast{position:fixed;bottom:1.2rem;left:50%;transform:translateX(-50%);background:#1A1A1A;color:#fff;padding:.7rem 1.2rem;border-radius:10px;font-size:.85rem;font-weight:600;opacity:0;pointer-events:none;transition:opacity .25s;z-index:200}
.toast.show{opacity:1}

/* section label */
.board-head{display:flex;align-items:center;gap:.6rem;margin:0 0 1rem}
.board-head h2{font-size:1.15rem;color:var(--brand);font-weight:800}
.board-head .rule{flex:1;height:2px;background:var(--gold);border-radius:2px}

/* parent filters */
.filters{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:1rem 1.2rem;box-shadow:0 4px 18px rgba(26,94,171,.08);margin-bottom:1.6rem}
.filter-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:.7rem}
@media(max-width:760px){.filter-grid{grid-template-columns:1fr 1fr}}
.filter-foot{display:flex;align-items:center;gap:1rem;margin-top:.85rem;flex-wrap:wrap}
.count{font-size:.82rem;color:var(--muted);font-weight:600}
.chk{display:flex;align-items:center;gap:.4rem;font-size:.85rem;font-weight:600}
.chk input{width:auto}
.clear{margin-left:auto}

/* teacher board card */
.teacher{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden;margin-bottom:1.1rem;box-shadow:0 1px 3px rgba(16,24,40,.05)}
.t-head{background:var(--sky);padding:1rem 1.2rem;display:flex;align-items:center;gap:.9rem;border-bottom:1px solid #dbe6f7}
.t-avatar{width:46px;height:46px;border-radius:50%;background:var(--brand);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:1.05rem;flex:none}
.t-name{font-size:1.12rem;font-weight:800;color:var(--brand)}
.t-subjects{font-size:.78rem;color:var(--muted);margin-top:.1rem}
.t-head .tally{margin-left:auto;text-align:right;font-size:.72rem;color:var(--muted);font-weight:600}
.t-head .tally b{color:var(--green);font-size:1.1rem;display:block}
.t-slots{padding:.3rem 1.2rem .8rem}
.srow{display:flex;align-items:center;gap:1rem;padding:.75rem 0;border-bottom:1px solid #eef1f6}
.srow:last-child{border-bottom:none}
.s-day{min-width:92px}
.sd-n{font-weight:800;font-size:.85rem;color:var(--brand)}
.s-time{font-size:.75rem;color:var(--muted)}
.s-info{flex:1;min-width:0}
.s-note{font-size:.77rem;color:var(--muted);margin-top:.3rem}
.s-status{font-size:.68rem;font-weight:800;padding:5px 12px;border-radius:20px;text-transform:uppercase;letter-spacing:.03em}
.st-open{background:#e2f6f3;color:#0f766e}
.st-booked{background:#fdecea;color:#c0392b}

/* dashboard grid + slot cards */
.grid{display:grid;grid-template-columns:350px 1fr;gap:1.3rem;align-items:start}
@media(max-width:840px){.grid{grid-template-columns:1fr}}
.slot{border:1px solid var(--border);border-radius:11px;padding:.85rem .95rem;margin-bottom:.75rem;display:flex;align-items:flex-start;gap:.85rem}
.slot.booked{background:#fdecea;border-color:#f4c6c0}
.slot-day{min-width:52px;text-align:center;background:var(--sky);border-radius:9px;padding:.45rem .3rem}
.sd-name{font-size:.66rem;font-weight:800;text-transform:uppercase;color:var(--brand)}
.slot-body{flex:1;min-width:0}
.slot-time{font-weight:800;font-size:1rem}
.slot-meta{font-size:.78rem;color:var(--muted);margin-top:.3rem}
.slot-actions{display:flex;flex-direction:column;gap:.35rem}

/* auth split screen */
.auth-shell{display:grid;grid-template-columns:1.1fr 1fr;min-height:calc(100vh - 53px)}
@media(max-width:820px){.auth-shell{grid-template-columns:1fr}.auth-aside{display:none}}
.auth-aside{background:linear-gradient(150deg,var(--brand),#0f3d70);color:#fff;padding:3rem;display:flex;flex-direction:column;justify-content:center;position:relative;overflow:hidden}
.auth-aside::before{content:"";position:absolute;top:-60px;right:-60px;width:220px;height:220px;border-radius:50%;background:rgba(232,160,32,.18)}
.auth-aside h2{font-size:1.8rem;font-weight:800;letter-spacing:-.02em;margin-bottom:.8rem;position:relative}
.auth-aside p{opacity:.9;font-size:1rem;max-width:38ch;position:relative}
.auth-aside ul{list-style:none;margin-top:1.8rem;position:relative}
.auth-aside li{display:flex;align-items:center;gap:.6rem;margin-bottom:.7rem;font-size:.92rem;opacity:.95}
.auth-aside li .tick{width:22px;height:22px;border-radius:50%;background:var(--gold);color:#1a1a1a;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:.7rem;flex:none}
.auth-main{display:flex;align-items:center;justify-content:center;padding:2.4rem 1.4rem;background:var(--sky)}
.auth-card{width:100%;max-width:410px;background:#fff;border:1px solid var(--border);border-radius:14px;padding:2rem 1.9rem;box-shadow:0 8px 30px rgba(26,94,171,.12)}
.auth-tabs{display:flex;background:var(--sky);border-radius:10px;padding:4px;margin-bottom:1.3rem}
.auth-tab{flex:1;border:none;background:transparent;padding:.6rem;border-radius:8px;font-family:var(--font);font-weight:700;font-size:.86rem;color:var(--muted);cursor:pointer}
.auth-tab.on{background:#fff;color:var(--brand);box-shadow:0 1px 3px rgba(16,24,40,.1)}
.auth-card h1{font-size:1.35rem;color:var(--brand);margin-bottom:.25rem;letter-spacing:-.02em}
.goldrule{height:3px;width:52px;background:var(--gold);border-radius:3px;margin:.35rem 0 .8rem}
.auth-card .sub{font-size:.86rem;color:var(--muted);margin-bottom:.4rem}

/* footer */
.site-foot{border-top:2px solid var(--gold);background:#fff;padding:1.4rem;text-align:center;color:var(--muted);font-size:.8rem}
.site-foot b{color:var(--brand)}

/* password strength meter (register) */
.seg{display:flex;gap:5px;margin-top:.55rem}
.seg span{flex:1;height:6px;border-radius:4px;background:#e6e6e6;transition:background .2s}
.meter-label{font-size:.74rem;font-weight:700;margin-top:.35rem;color:var(--muted)}

/* subject + grade rows (register) */
.subj-row{display:grid;grid-template-columns:1fr 120px 34px;gap:.5rem;align-items:center;margin-top:.5rem}
.subj-row .s-subject,.subj-row .s-grade{margin:0}
.subj-row .rm{border:1px solid var(--border);background:#fff;color:var(--red);border-radius:9px;height:40px;cursor:pointer;font-size:1.1rem;font-weight:700;font-family:var(--font)}
.subj-row .rm:hover{background:var(--red-bg)}
.add-subj{margin-top:.7rem;background:var(--sky);color:var(--brand);border:1px dashed #9db9e0;border-radius:9px;padding:.6rem;width:100%;font-weight:700;font-size:.85rem;cursor:pointer;font-family:var(--font)}
.add-subj:hover{background:#e0eafb}

/* timezone selector in nav */
.tz-select{padding:.4rem .55rem;border:1px solid #cddcf3;border-radius:8px;background:var(--sky);color:var(--brand);font-family:var(--font);font-size:.78rem;font-weight:700;cursor:pointer}
.tz-tag{display:inline-block;font-size:.6rem;font-weight:800;color:var(--muted);letter-spacing:.04em;margin-left:.35rem;vertical-align:middle}
.tz-hint{font-size:.74rem;color:var(--muted);margin-top:.35rem}