/* ===== RESET & BASE ===== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  --bg:#0d1117;--bg2:#161b22;--bg3:#21262d;--border:#30363d;
  --text:#e6edf3;--text2:#8b949e;
  --accent:#4f8aff;--accent2:#2ecc71;--danger:#e74c3c;--warning:#f39c12;--purple:#9b59b6;
  --radius:12px;--shadow:0 4px 24px rgba(0,0,0,.4);
  --font:'Be Vietnam Pro',sans-serif;
}
html{scroll-behavior:smooth}
body{font-family:var(--font);background:var(--bg);color:var(--text);min-height:100vh;overflow-x:hidden}
::-webkit-scrollbar{width:6px}::-webkit-scrollbar-track{background:var(--bg2)}::-webkit-scrollbar-thumb{background:var(--border);border-radius:3px}
a{color:inherit;text-decoration:none}
input,select,textarea,button{font-family:var(--font)}

/* ===== NAVBAR ===== */
.navbar{position:fixed;top:0;left:0;right:0;height:64px;background:rgba(13,17,23,.92);backdrop-filter:blur(16px);border-bottom:1px solid var(--border);z-index:1000;transition:box-shadow .3s}
.navbar.scrolled{box-shadow:0 4px 32px rgba(0,0,0,.5)}
.nav-inner{max-width:1300px;margin:0 auto;height:100%;display:flex;align-items:center;gap:24px;padding:0 24px}
.logo{display:flex;align-items:center;gap:8px;font-size:1.2rem;font-weight:700;color:var(--text);text-decoration:none;letter-spacing:-.5px;white-space:nowrap}
.logo-icon{color:var(--accent);font-size:1.4rem}
.nav-links{display:flex;gap:2px;flex:1}
.nav-link{padding:6px 12px;border-radius:8px;color:var(--text2);font-size:.85rem;font-weight:500;transition:all .2s}
.nav-link:hover{background:var(--bg3);color:var(--text)}
.nav-link.active{background:rgba(79,138,255,.15);color:var(--accent)}
.nav-right{display:flex;align-items:center;gap:12px;margin-left:auto}
.nav-user-info{display:flex;flex-direction:column;align-items:flex-end;gap:2px}
.nav-name{font-size:.78rem;font-weight:600}
.nav-role-badge{font-size:.65rem;font-weight:700;padding:2px 8px;border-radius:20px}
.nav-role-badge.teacher{background:rgba(79,138,255,.2);color:var(--accent)}
.nav-role-badge.student{background:rgba(46,204,113,.2);color:var(--accent2)}
.avatar{width:36px;height:36px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:.72rem;font-weight:800;color:#fff;cursor:pointer;flex-shrink:0}
.btn-logout{background:none;border:none;color:var(--text2);font-size:1.1rem;cursor:pointer;padding:4px;transition:color .2s;text-decoration:none}
.btn-logout:hover{color:var(--danger)}

/* ===== MAIN ===== */
.main-content{max-width:1300px;margin:0 auto;padding:88px 24px 48px}

/* ===== PAGE HEADER ===== */
.page-header{display:flex;justify-content:space-between;align-items:flex-end;margin-bottom:28px;flex-wrap:wrap;gap:16px}
.page-sub{font-size:.75rem;font-weight:700;color:var(--accent);text-transform:uppercase;letter-spacing:1px;margin-bottom:4px}
.page-title{font-family:'Playfair Display',serif;font-size:2rem;font-weight:800;background:linear-gradient(135deg,var(--text),var(--text2));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;line-height:1.2}

/* ===== CARDS ===== */
.card{background:var(--bg2);border:1px solid var(--border);border-radius:var(--radius);padding:20px}
.card-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:16px}
.card-header h3{font-size:.95rem;font-weight:700}
.mt-20{margin-top:16px}

/* ===== STATS ===== */
.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin-bottom:20px}
.stat-card{background:var(--bg2);border:1px solid var(--border);border-radius:var(--radius);padding:18px;position:relative;overflow:hidden;transition:transform .2s,border-color .2s}
.stat-card:hover{transform:translateY(-3px);border-color:var(--accent)}
.stat-card::before{content:'';position:absolute;top:0;left:0;right:0;height:3px;background:var(--accent)}
.stat-icon{font-size:1.4rem;margin-bottom:10px}
.stat-val{font-size:1.9rem;font-weight:800;line-height:1}
.stat-label{font-size:.78rem;color:var(--text2);margin-top:4px}

/* ===== LAYOUT ===== */
.row-2{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-bottom:16px}
.row-2-3{display:grid;grid-template-columns:1fr 2fr;gap:20px;align-items:start}

/* ===== TABLES ===== */
.table-wrap{overflow-x:auto}
.data-table{width:100%;border-collapse:collapse;font-size:.875rem}
.data-table th{padding:10px 12px;text-align:left;font-size:.72rem;font-weight:700;color:var(--text2);text-transform:uppercase;letter-spacing:.5px;border-bottom:1px solid var(--border)}
.data-table td{padding:12px;border-bottom:1px solid rgba(48,54,61,.5)}
.data-table tr:last-child td{border-bottom:none}
.data-table tr:hover td{background:rgba(255,255,255,.02)}

/* ===== TAGS & STATUS ===== */
.tag{padding:3px 10px;border-radius:20px;font-size:.72rem;font-weight:700;display:inline-block}
.status{padding:3px 10px;border-radius:20px;font-size:.72rem;font-weight:600;display:inline-block}
.status.upcoming,.status.active{background:rgba(46,204,113,.15);color:var(--accent2)}
.status.draft{background:rgba(139,148,158,.15);color:var(--text2)}
.status.closed{background:rgba(231,76,60,.15);color:var(--danger)}
.badge{padding:3px 10px;border-radius:20px;font-size:.72rem;font-weight:700;background:rgba(79,138,255,.15);color:var(--accent)}
.badge.red{background:rgba(231,76,60,.15);color:var(--danger)}

/* ===== BUTTONS ===== */
.btn-primary{padding:10px 20px;background:var(--accent);color:#fff;border:none;border-radius:8px;font-size:.875rem;font-weight:600;cursor:pointer;transition:all .2s;display:inline-block;text-decoration:none}
.btn-primary:hover{background:#3a72e8;transform:translateY(-1px);box-shadow:0 4px 16px rgba(79,138,255,.4)}
.btn-full{width:100%;text-align:center}
.btn-sm{padding:6px 12px;background:var(--bg3);color:var(--text2);border:1px solid var(--border);border-radius:6px;font-size:.78rem;font-weight:600;cursor:pointer;transition:all .2s;display:inline-block;text-decoration:none}
.btn-sm:hover{color:var(--text);border-color:var(--text2)}
.btn-sm-p{padding:8px 16px;background:var(--accent);color:#fff;border:1px solid transparent;border-radius:8px;font-size:.82rem;font-weight:600;cursor:pointer;transition:all .2s;display:inline-block}
.btn-sm.btn-danger{color:var(--danger);border-color:rgba(231,76,60,.3)}
.btn-sm.btn-accent{background:rgba(79,138,255,.15);color:var(--accent);border-color:rgba(79,138,255,.3)}
.btn-copy{background:none;border:1px solid var(--border);border-radius:6px;padding:3px 8px;cursor:pointer;font-size:.8rem;color:var(--text2);transition:all .2s}
.btn-copy:hover{border-color:var(--accent);color:var(--accent)}

/* ===== FORM ELEMENTS ===== */
.form-group{margin-bottom:16px}
.form-label{display:block;font-size:.78rem;font-weight:700;color:var(--text2);margin-bottom:6px;text-transform:uppercase;letter-spacing:.5px}
.req{color:var(--danger)}
.form-input,.form-select,.form-textarea{width:100%;padding:10px 14px;background:var(--bg3);border:1px solid var(--border);border-radius:8px;color:var(--text);font-size:.875rem;outline:none;transition:border-color .2s}
.form-input:focus,.form-select:focus,.form-textarea:focus{border-color:var(--accent)}
.form-textarea{resize:vertical;min-height:90px}
.form-row{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.form-actions{display:flex;gap:10px;justify-content:flex-end}

/* ===== ALERTS ===== */
.alert{padding:12px 16px;border-radius:8px;font-size:.875rem;margin-bottom:16px;display:flex;align-items:flex-start;gap:8px}
.alert-error{background:rgba(231,76,60,.12);border:1px solid rgba(231,76,60,.3);color:#ff7f7f}
.alert-success{background:rgba(46,204,113,.12);border:1px solid rgba(46,204,113,.3);color:var(--accent2)}
.alert-info{background:rgba(79,138,255,.1);border:1px solid rgba(79,138,255,.25);color:#7fb3ff}

/* ===== FLASH ===== */
.flash{position:fixed;top:70px;right:20px;z-index:2000;padding:12px 18px;border-radius:10px;font-size:.875rem;font-weight:500;display:flex;align-items:center;gap:10px;box-shadow:var(--shadow);max-width:380px;animation:slideIn .3s ease}
.flash-success{background:var(--bg2);border-left:4px solid var(--accent2);border:1px solid var(--border);border-left-width:4px}
.flash-error{background:var(--bg2);border-left:4px solid var(--danger);border:1px solid var(--border);border-left-width:4px}
.flash-info{background:var(--bg2);border-left:4px solid var(--accent);border:1px solid var(--border);border-left-width:4px}
.flash-close{background:none;border:none;color:var(--text2);cursor:pointer;margin-left:auto;font-size:.9rem}
@keyframes slideIn{from{opacity:0;transform:translateX(20px)}to{opacity:1;transform:translateX(0)}}

/* ===== MODAL ===== */
.modal-overlay{position:fixed;inset:0;background:rgba(0,0,0,.7);backdrop-filter:blur(4px);z-index:2000;display:none;align-items:center;justify-content:center;padding:20px}
.modal-overlay.open{display:flex;animation:fadeIn .2s ease}
.modal{background:var(--bg2);border:1px solid var(--border);border-radius:16px;width:100%;max-width:560px;max-height:90vh;overflow-y:auto;box-shadow:0 24px 80px rgba(0,0,0,.6)}
.modal-header{display:flex;justify-content:space-between;align-items:center;padding:18px 22px;border-bottom:1px solid var(--border)}
.modal-header h3{font-size:1rem;font-weight:700}
.modal-close{background:none;border:none;color:var(--text2);font-size:1rem;cursor:pointer;padding:4px;transition:color .2s}
.modal-close:hover{color:var(--text)}
.modal-body{padding:22px}
@keyframes fadeIn{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}

/* ===== EMPTY STATES ===== */
.empty-state{display:flex;flex-direction:column;align-items:center;justify-content:center;padding:32px;text-align:center;color:var(--text2)}
.empty-state.large{padding:64px 32px}
.empty-icon{font-size:2.5rem;margin-bottom:12px}
.empty-state h3{color:var(--text);font-size:1.1rem;margin-bottom:8px}
.empty-state p{font-size:.875rem}
.mt-16{margin-top:16px}

/* ===== CLASS LIST (dashboard) ===== */
.class-list{display:flex;flex-direction:column;gap:8px}
.class-item{display:flex;align-items:center;gap:12px;padding:12px;border-radius:8px;border:1px solid transparent;transition:all .2s;cursor:pointer}
.class-item:hover{background:var(--bg3);border-color:var(--border)}
.class-icon{width:40px;height:40px;border-radius:8px;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:.85rem;flex-shrink:0}
.class-name{font-weight:600;font-size:.875rem}
.class-meta{font-size:.75rem;color:var(--text2)}
.class-code{font-family:monospace;font-size:.7rem;background:var(--bg3);padding:2px 8px;border-radius:4px;color:var(--text2);margin-left:auto}

/* ===== CLASS GRID (student) ===== */
.class-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:14px}
.class-card{background:var(--bg2);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden;transition:all .25s;cursor:pointer}
.class-card:hover{border-color:var(--accent);transform:translateY(-2px)}
.class-card-header{padding:18px;border-bottom:1px solid var(--border)}
.class-card-name{font-weight:700;margin-bottom:4px}
.class-card-subject{font-size:.78rem;color:var(--text2)}
.class-card-body{padding:12px;font-size:.78rem;color:var(--text2)}

/* ===== TEACHER CLASS CARDS ===== */
.class-grid-teacher{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:16px}
.teacher-class-card{background:var(--bg2);border:1px solid var(--border);border-radius:var(--radius);padding:20px;transition:all .25s}
.teacher-class-card:hover{border-color:var(--accent)}
.tcc-header{display:flex;justify-content:space-between;align-items:flex-start;margin-bottom:10px}
.tcc-name{font-size:1rem;font-weight:700}
.tcc-desc{font-size:.8rem;color:var(--text2);margin-bottom:12px;line-height:1.5}
.tcc-stats{display:flex;gap:16px;font-size:.78rem;color:var(--text2);margin-bottom:14px}
.tcc-code{display:flex;align-items:center;gap:8px;padding:10px;background:var(--bg3);border-radius:8px;margin-bottom:14px;flex-wrap:wrap}
.code-label{font-size:.72rem;color:var(--text2);font-weight:600;text-transform:uppercase}
.code-val{font-family:monospace;font-weight:800;font-size:.95rem;letter-spacing:1px;color:var(--accent);background:none;border:none;cursor:text}
.tcc-actions{display:flex;gap:8px;flex-wrap:wrap}

/* ===== JOIN INFO BAR ===== */
.join-info-bar{display:flex;align-items:center;gap:12px;padding:12px 16px;background:var(--bg3);border:1px solid var(--border);border-radius:8px;margin-bottom:20px;flex-wrap:wrap;font-size:.875rem}
.join-info-bar code{font-family:monospace;font-weight:800;font-size:1rem;color:var(--accent);letter-spacing:1px}

/* ===== MEMBER GRID ===== */
.member-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:10px}
.member-chip{display:flex;align-items:center;gap:10px;padding:10px;background:var(--bg3);border-radius:8px}
.member-av{width:36px;height:36px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:.72rem;flex-shrink:0}
.member-name{font-size:.875rem;font-weight:600}
.member-school{font-size:.72rem;color:var(--text2)}

/* ===== SCORE CHIPS ===== */
.score-chip{padding:4px 12px;border-radius:20px;font-weight:800;font-size:.875rem}
.score-chip.green{background:rgba(46,204,113,.15);color:var(--accent2)}
.score-chip.orange{background:rgba(243,156,18,.15);color:var(--warning)}
.score-chip.red{background:rgba(231,76,60,.15);color:var(--danger)}
.score-num{font-size:1.4rem;font-weight:800;padding:4px 12px;border-radius:8px}
.score-num.green{color:var(--accent2)}
.score-num.orange{color:var(--warning)}
.score-num.red{color:var(--danger)}

/* ===== SUBMISSION LIST ===== */
.submission-list-compact{display:flex;flex-direction:column;gap:8px;max-height:360px;overflow-y:auto}
.sub-item-compact{display:flex;align-items:center;gap:10px;padding:10px;border-radius:8px;border:1px solid transparent;transition:all .2s;cursor:pointer}
.sub-item-compact:hover{background:var(--bg3);border-color:var(--border)}
.sub-avatar{flex-shrink:0;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:.72rem}
.sub-info .sub-name{font-weight:600;font-size:.875rem}
.sub-info .sub-meta{font-size:.75rem;color:var(--text2)}

/* ===== EXAM OPEN LIST (student) ===== */
.exam-open-list{display:flex;flex-direction:column;gap:12px}
.exam-open-item{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px;background:var(--bg3);border-radius:8px}
.exam-open-title{font-weight:600;font-size:.875rem;margin-bottom:3px}
.exam-open-meta{font-size:.75rem;color:var(--text2)}

/* ===== SCORE LIST ===== */
.score-list{display:flex;flex-direction:column;gap:10px}
.score-item{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px;background:var(--bg3);border-radius:8px}
.score-title{font-weight:600;font-size:.875rem;margin-bottom:3px}
.score-meta{font-size:.75rem;color:var(--text2)}

/* ===== EXAM BUILDER ===== */
.question-builder{background:var(--bg3);border:1px solid var(--border);border-radius:10px;padding:16px;animation:fadeIn .3s ease}
.q-builder-header{display:flex;align-items:center;gap:10px}
.q-num-badge{width:26px;height:26px;background:var(--accent);color:#fff;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:.75rem;font-weight:800;flex-shrink:0}
.q-type-badge{padding:2px 10px;border-radius:20px;font-size:.72rem;font-weight:700}
.q-type-badge.multiple_choice{background:rgba(79,138,255,.2);color:var(--accent)}
.q-type-badge.essay{background:rgba(155,89,182,.2);color:var(--purple)}
.q-pts{margin-left:auto;font-size:.75rem;color:var(--text2)}
.options-wrap{display:flex;flex-direction:column;gap:8px;margin-top:8px}
.option-row{display:flex;align-items:center;gap:10px}
.option-letter{width:24px;height:24px;border-radius:50%;background:var(--bg2);display:flex;align-items:center;justify-content:center;font-size:.72rem;font-weight:800;flex-shrink:0}

/* ===== TAKE EXAM ===== */
.exam-header-bar{display:flex;justify-content:space-between;align-items:center;padding:16px 20px;background:var(--bg2);border:1px solid var(--border);border-radius:var(--radius);margin-bottom:20px;position:sticky;top:70px;z-index:100}
.exam-timer{display:flex;align-items:center;gap:8px;font-size:1.2rem;font-weight:800;color:var(--accent2)}
.question-card{background:var(--bg2);border:1px solid var(--border);border-radius:var(--radius);padding:20px;margin-bottom:14px}
.question-card.correct{border-color:rgba(46,204,113,.4);background:rgba(46,204,113,.04)}
.question-card.wrong{border-color:rgba(231,76,60,.3);background:rgba(231,76,60,.04)}
.q-header{display:flex;align-items:center;gap:10px;margin-bottom:12px}
.q-text{font-size:.95rem;line-height:1.7;margin-bottom:16px}
.q-options{display:flex;flex-direction:column;gap:8px}
.q-option{display:flex;align-items:center;gap:12px;padding:12px 14px;border-radius:8px;border:1px solid var(--border);cursor:pointer;transition:all .2s;font-size:.875rem}
.q-option:hover{border-color:var(--accent);background:rgba(79,138,255,.06)}
.q-option.selected{border-color:var(--accent);background:rgba(79,138,255,.12);color:var(--text)}
.opt-dot{width:16px;height:16px;border-radius:50%;border:2px solid var(--border);flex-shrink:0;transition:all .2s}
.q-option.selected .opt-dot{background:var(--accent);border-color:var(--accent)}
.exam-submit-bar{display:flex;justify-content:space-between;align-items:center;padding:16px 20px;background:var(--bg2);border:1px solid var(--border);border-radius:var(--radius);position:sticky;bottom:16px}

/* ===== GRADE PAGE ===== */
.qa-card{margin-bottom:14px}
.answer-row{display:flex;flex-direction:column;gap:6px;margin-top:12px;padding:10px;background:var(--bg3);border-radius:8px;font-size:.875rem}
.answer-label{color:var(--text2);font-weight:600;margin-right:8px}
.answer-val.green{color:var(--accent2)}
.answer-val.red{color:var(--danger)}
.answer-status{padding:2px 10px;border-radius:20px;font-size:.72rem;font-weight:700;margin-left:auto}
.answer-status.correct{background:rgba(46,204,113,.15);color:var(--accent2)}
.answer-status.wrong{background:rgba(231,76,60,.15);color:var(--danger)}
.answer-status.skip{background:rgba(139,148,158,.15);color:var(--text2)}
.essay-answer{margin-top:12px}
.essay-label{font-size:.78rem;font-weight:700;color:var(--text2);text-transform:uppercase;letter-spacing:.5px;margin-bottom:6px}
.essay-content{background:var(--bg3);padding:12px;border-radius:8px;font-size:.875rem;line-height:1.7}
.student-info-box{display:flex;align-items:center;gap:12px;padding:12px;background:var(--bg3);border-radius:8px}
.sib-av{width:42px;height:42px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:800;flex-shrink:0}
/* ===== FORUM ===== */
.forum-layout{display:grid;grid-template-columns:1fr 280px;gap:20px;align-items:start}
.forum-sidebar{display:flex;flex-direction:column;gap:14px;position:sticky;top:80px}
.tag-filter-bar{display:flex;gap:6px;flex-wrap:wrap;margin-bottom:16px}
.tag-filter{padding:5px 14px;border-radius:20px;border:1px solid var(--border);font-size:.78rem;font-weight:600;color:var(--text2);cursor:pointer;transition:all .2s}
.tag-filter:hover,.tag-filter.active{background:rgba(79,138,255,.15);color:var(--accent);border-color:rgba(79,138,255,.3)}

.forum-post-card{display:block;background:var(--bg2);border:1px solid var(--border);border-radius:var(--radius);padding:18px;margin-bottom:12px;transition:all .25s;cursor:pointer}
.forum-post-card:hover{border-color:var(--accent);transform:translateX(3px)}
.post-card-top{display:flex;align-items:flex-start;gap:10px;margin-bottom:8px}
.post-card-title{font-weight:700;font-size:.95rem;flex:1}
.post-card-body{font-size:.85rem;color:var(--text2);line-height:1.5;margin-bottom:12px}
.post-card-footer{display:flex;justify-content:space-between;align-items:center;font-size:.75rem}
.post-card-author{display:flex;align-items:center;gap:8px}
.post-card-stats{display:flex;gap:14px;color:var(--text2)}
.mini-av{width:22px;height:22px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:.6rem;font-weight:800}
.post-time-sm{color:var(--text2)}

/* Single post */
.forum-post-full{margin-bottom:16px}
.post-author-row{display:flex;align-items:center;gap:12px;margin-bottom:16px;flex-wrap:wrap}
.author-av{width:40px;height:40px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:800;flex-shrink:0}
.author-name{font-weight:700;font-size:.9rem;display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.post-time{font-size:.75rem;color:var(--text2)}
.post-full-title{font-size:1.4rem;font-weight:800;margin-bottom:14px;line-height:1.4}
.post-full-body{font-size:.95rem;line-height:1.8;color:var(--text2);margin-bottom:16px}
.post-actions-row{display:flex;gap:16px;align-items:center;padding-top:14px;border-top:1px solid var(--border)}
.like-btn{background:none;border:1px solid var(--border);border-radius:20px;padding:6px 14px;font-size:.8rem;cursor:pointer;color:var(--text2);transition:all .2s}
.like-btn:hover,.like-btn.liked{background:rgba(231,76,60,.1);border-color:rgba(231,76,60,.4);color:#ff6b81}
.role-pill{padding:2px 8px;border-radius:20px;font-size:.65rem;font-weight:700}
.role-pill.teacher{background:rgba(79,138,255,.2);color:var(--accent)}
.role-pill.student{background:rgba(46,204,113,.15);color:var(--accent2)}
.pin-badge{padding:2px 10px;border-radius:20px;font-size:.72rem;font-weight:700;background:rgba(243,156,18,.15);color:var(--warning);white-space:nowrap}

/* Comments */
.comment-list{display:flex;flex-direction:column;gap:14px;margin-bottom:20px}
.comment-item{padding:14px;background:var(--bg3);border-radius:10px;border:1px solid var(--border)}
.comment-item.is-solution{border-color:rgba(46,204,113,.4);background:rgba(46,204,113,.05)}
.solution-badge{font-size:.75rem;font-weight:700;color:var(--accent2);margin-bottom:8px}
.comment-author-row{display:flex;align-items:center;gap:8px;margin-bottom:8px;flex-wrap:wrap}
.comment-av{width:30px;height:30px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:.65rem;font-weight:800;flex-shrink:0}
.comment-author{font-weight:700;font-size:.85rem}
.comment-time{font-size:.72rem;color:var(--text2)}
.comment-body{font-size:.875rem;line-height:1.7;color:var(--text2)}
.reply-toggle{background:none;border:none;color:var(--accent);font-size:.78rem;cursor:pointer;padding:6px 0 0;font-family:var(--font);transition:opacity .2s}
.reply-toggle:hover{opacity:.7}
.reply-form{margin-top:10px;padding-top:10px;border-top:1px solid var(--border)}
.add-comment-box{display:flex;gap:12px;align-items:flex-start;padding-top:16px;border-top:1px solid var(--border)}
.add-comment-av{width:36px;height:36px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:.72rem;flex-shrink:0;margin-top:4px}

/* Sidebar lists */
.sidebar-title{font-size:.875rem;font-weight:700;margin-bottom:12px}
.tag-sidebar-list{list-style:none;display:flex;flex-direction:column;gap:6px}
.tag-sidebar-list a{font-size:.82rem;color:var(--text2);padding:4px 8px;border-radius:6px;display:block;transition:all .2s}
.tag-sidebar-list a:hover,.tag-sidebar-list a.active{color:var(--accent);background:rgba(79,138,255,.08)}
.forum-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:8px;text-align:center}
.fs-item{padding:8px;background:var(--bg3);border-radius:8px}
.fs-num{display:block;font-size:1.1rem;font-weight:800;color:var(--accent)}
.fs-label{font-size:.7rem;color:var(--text2)}

/* ===== AUTH PAGES ===== */
.auth-body{background:var(--bg);display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:100vh;padding:20px;position:relative}
.auth-bg{position:fixed;inset:0;pointer-events:none;overflow:hidden;z-index:0}
.auth-blob{position:absolute;border-radius:50%;filter:blur(80px);opacity:.12}
.b1{width:500px;height:500px;background:var(--accent);top:-100px;left:-100px}
.b2{width:400px;height:400px;background:var(--purple);bottom:-100px;right:-50px}
.b3{width:300px;height:300px;background:var(--accent2);top:50%;left:50%;transform:translate(-50%,-50%)}
.auth-wrap{position:relative;z-index:1;width:100%;max-width:460px}
.auth-logo{display:flex;align-items:center;gap:8px;font-size:1.3rem;font-weight:700;color:var(--text);margin-bottom:24px;justify-content:center}
.auth-card{background:var(--bg2);border:1px solid var(--border);border-radius:16px;padding:28px}
.auth-card-header{margin-bottom:22px}
.auth-card-header h1{font-family:'Playfair Display',serif;font-size:1.7rem;font-weight:800;margin-bottom:4px}
.auth-card-header p{font-size:.875rem;color:var(--text2)}
.auth-form{}
.input-eye-wrap{position:relative}
.input-eye-wrap .form-input{padding-right:44px}
.eye-btn{position:absolute;right:10px;top:50%;transform:translateY(-50%);background:none;border:none;cursor:pointer;color:var(--text2);font-size:.9rem;padding:4px}
.auth-switch{text-align:center;font-size:.875rem;color:var(--text2);margin-top:16px}
.auth-switch a{color:var(--accent);font-weight:600}
.auth-demo{margin-top:20px;padding-top:16px;border-top:1px solid var(--border)}
.demo-label{font-size:.75rem;color:var(--text2);text-align:center;margin-bottom:10px;text-transform:uppercase;letter-spacing:.5px}
.demo-accounts{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.demo-btn{padding:8px;background:var(--bg3);border:1px solid var(--border);border-radius:8px;cursor:pointer;color:var(--text2);font-size:.8rem;font-weight:600;transition:all .2s}
.demo-btn:hover{border-color:var(--accent);color:var(--text)}
.reg-tabs{display:flex;background:var(--bg3);border-radius:8px;padding:3px;gap:3px;margin-bottom:20px}
.reg-tab{flex:1;padding:8px;background:transparent;border:none;border-radius:6px;cursor:pointer;color:var(--text2);font-size:.85rem;font-weight:600;transition:all .2s}
.reg-tab.active{background:var(--accent);color:#fff}
.hidden{display:none!important}

/* ===== HAMBURGER BUTTON ===== */
.hamburger{display:none;flex-direction:column;justify-content:center;gap:5px;width:36px;height:36px;background:var(--bg3);border:1px solid var(--border);border-radius:8px;cursor:pointer;padding:7px;flex-shrink:0}
.hamburger span{display:block;height:2px;background:var(--text2);border-radius:2px;transition:all .3s}
.hamburger.open span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.hamburger.open span:nth-child(2){opacity:0}
.hamburger.open span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}
.desktop-only{display:flex}

/* ===== MOBILE SLIDE-DOWN MENU ===== */
.mobile-menu{position:fixed;top:64px;left:0;right:0;background:var(--bg2);border-bottom:1px solid var(--border);z-index:999;transform:translateY(-110%);transition:transform .3s cubic-bezier(.4,0,.2,1);box-shadow:0 8px 32px rgba(0,0,0,.5)}
.mobile-menu.open{transform:translateY(0)}
.mobile-menu-header{display:flex;align-items:center;justify-content:space-between;padding:16px 20px;border-bottom:1px solid var(--border)}
.mobile-menu-nav{display:flex;flex-direction:column;padding:8px 12px}
.mobile-nav-link{display:flex;align-items:center;gap:14px;padding:13px 12px;border-radius:10px;color:var(--text2);font-size:.95rem;font-weight:500;transition:all .2s}
.mobile-nav-link:hover{background:var(--bg3);color:var(--text)}
.mobile-nav-link.active{background:rgba(79,138,255,.12);color:var(--accent)}
.mobile-nav-icon{font-size:1.2rem;width:28px;text-align:center}
.mobile-menu-footer{padding:12px 20px 16px;border-top:1px solid var(--border)}
.mobile-logout{display:flex;align-items:center;gap:8px;color:var(--danger);font-size:.875rem;font-weight:600;padding:10px 12px;border-radius:8px;transition:background .2s}
.mobile-logout:hover{background:rgba(231,76,60,.08)}
.mobile-overlay{display:none;position:fixed;inset:0;z-index:998;background:rgba(0,0,0,.4);backdrop-filter:blur(2px)}
.mobile-overlay.show{display:block}

/* ===== BOTTOM NAV BAR ===== */
.bottom-nav{display:none;position:fixed;bottom:0;left:0;right:0;height:62px;background:rgba(22,27,34,.96);backdrop-filter:blur(16px);border-top:1px solid var(--border);z-index:997;padding:0 4px}
.bottom-nav{align-items:stretch;justify-content:space-around}
.bottom-nav-item{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:3px;flex:1;padding:6px 4px;color:var(--text2);font-size:.6rem;font-weight:600;transition:color .2s;min-width:0;text-decoration:none}
.bottom-nav-item:hover,.bottom-nav-item.active{color:var(--accent)}
.bottom-nav-item.active .bottom-nav-icon{background:rgba(79,138,255,.15);border-radius:20px;padding:2px 12px}
.bottom-nav-icon{font-size:1.3rem;line-height:1;transition:all .2s}
.bottom-nav-label{white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:56px;text-align:center}

/* ===== FOOTER ===== */
.site-footer{border-top:1px solid var(--border);padding:20px 24px;margin-top:40px}
.footer-inner{max-width:1300px;margin:0 auto;display:flex;justify-content:space-between;align-items:center;font-size:.8rem;color:var(--text2);flex-wrap:wrap;gap:8px}

/* ===== RESPONSIVE ===== */
@media(max-width:900px){
  .stats-grid{grid-template-columns:1fr 1fr}
  .row-2,.row-2-3,.forum-layout{grid-template-columns:1fr}
  .forum-sidebar{display:none}
  .nav-links{display:none}          /* ẩn desktop links, dùng hamburger + bottom nav */
  .hamburger{display:flex}
  .desktop-only{display:none}
  .bottom-nav{display:flex}
  .nav-user-info{display:none}      /* ẩn tên trên navbar mobile, đã có trong menu */
  .main-content{padding-bottom:80px}/* chừa chỗ cho bottom nav */
  .form-row{grid-template-columns:1fr}
  .site-footer{margin-bottom:62px}  /* đẩy footer lên trên bottom nav */
}
@media(max-width:600px){
  .stats-grid{grid-template-columns:1fr}
  .page-title{font-size:1.5rem}
  .exam-header-bar{position:relative;top:auto}
  .nav-inner{padding:0 16px;gap:12px}
  .main-content{padding:80px 16px 80px}
}
/* ── New question type badges ──────────────────────────── */
.q-type-badge.short_answer{background:rgba(46,204,113,.2);color:var(--accent2)}
.q-type-badge.true_false{background:rgba(243,156,18,.2);color:var(--warning)}

/* ── Scroll card lists (fixed height, internal scroll) ─── */
.scroll-card-list{max-height:320px;overflow-y:auto;display:flex;flex-direction:column;gap:6px;padding-right:2px}
.scroll-card-list::-webkit-scrollbar{width:4px}
.scroll-card-list::-webkit-scrollbar-thumb{background:var(--border);border-radius:2px}

/* ── Class grid scroll ─────────────────────────────────── */
.class-grid-scroll{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:14px;max-height:340px;overflow-y:auto}

/* ── Member chip updated ───────────────────────────────── */
.member-chip{display:flex;align-items:center;gap:10px;padding:10px 12px;background:var(--bg3);border-radius:10px;border:1px solid var(--border)}

/* ── Answer status in grade/review ────────────────────── */
.answer-status{margin-left:auto;font-size:.75rem;font-weight:700;padding:3px 10px;border-radius:20px;display:inline-flex;align-items:center;gap:4px}
.answer-status.correct{background:rgba(46,204,113,.15);color:var(--accent2)}
.answer-status.wrong{background:rgba(231,76,60,.15);color:var(--danger)}
.answer-status.skip{background:var(--bg3);color:var(--text2)}

/* ── Forum nested reply indent ─────────────────────────── */
.reply-form{background:var(--bg3);border-radius:10px;padding:12px;margin-top:8px}

/* ── Score item flex fix ────────────────────────────────── */
.score-item{display:flex;align-items:center;gap:12px;padding:10px 12px;background:var(--bg3);border-radius:8px}
.score-title{font-weight:600;font-size:.875rem;margin-bottom:2px}
.score-meta{font-size:.75rem;color:var(--text2)}