/* =============================================================
   SaaS App Portal — UI Kit  v2
   Single source of truth. No inline styles in views.
   ============================================================= */

/* ── Design tokens ────────────────────────────────────────── */
:root {
    --sp-1:8px; --sp-2:16px; --sp-3:24px; --sp-4:32px; --sp-5:40px;
    --c-primary:#6366f1; --c-primary-dark:#4f46e5; --c-primary-light:#eef2ff;
    --c-primary-border:#c7d2fe; --c-primary-deep:#3730a3;
    --c-success:#10b981; --c-success-light:#f0fdf4; --c-success-border:#a7f3d0; --c-success-text:#065f46;
    --c-warning:#f59e0b; --c-warning-light:rgba(245,158,11,.1); --c-warning-text:#92400e;
    --c-danger:#ef4444; --c-danger-light:#fef2f2; --c-danger-border:#fca5a5; --c-danger-text:#991b1b;
    --c-text:#111827; --c-text-2:#374151; --c-text-3:#6b7280; --c-text-muted:#9ca3af;
    --c-border:#e5e7eb; --c-border-light:#f3f4f6; --c-row-border:#f9fafb;
    --c-bg:#f8f8fc; --c-white:#fff;
    --r-sm:6px; --r-md:8px; --r-lg:12px; --r-xl:16px; --r-pill:20px;
    --t-xs:12px; --t-sm:13px; --t-base:14.5px; --t-md:15px; --t-lg:20px; --t-xl:26px;
}

/* ── Reset ────────────────────────────────────────────────── */
*,*::before,*::after{font-family:'DM Sans',sans-serif;box-sizing:border-box;margin:0;padding:0;}
body{background:var(--c-bg);color:var(--c-text);min-height:100vh;}

/* ── Sidebar layout shell ─────────────────────────────────── */
.app-wrapper { margin-left: 220px; min-height: 100vh; }
.app-topbar  { display: none; }  /* hidden on desktop */

/* ── Left sidebar ─────────────────────────────────────────── */
.app-sidebar {
    position: fixed;
    left: 0; top: 0;
    width: 220px;
    height: 100vh;
    background: var(--c-white);
    border-right: 1px solid var(--c-border);
    display: flex;
    flex-direction: column;
    z-index: 100;
    overflow-y: auto;
    scrollbar-width: none;
}
.app-sidebar::-webkit-scrollbar { display: none; }

/* Brand */
.app-sidebar-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 20px 16px 18px;
    border-bottom: 1px solid var(--c-border-light);
    text-decoration: none;
    flex-shrink: 0;
}
.app-sidebar-logo  { width: 36px; height: 36px; object-fit: contain; flex-shrink: 0; }
.app-sidebar-title { font-size: 15px; font-weight: 700; color: var(--c-text); letter-spacing: -0.02em; }

/* User info */
.app-sidebar-user-section {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 16px;
    border-bottom: 1px solid var(--c-border-light);
    flex-shrink: 0;
}
.app-sidebar-avatar {
    width: 32px; height: 32px;
    border-radius: var(--r-md);
    background: var(--c-primary);
    color: var(--c-white);
    display: flex; align-items: center; justify-content: center;
    font-size: 13px; font-weight: 700;
    flex-shrink: 0;
}
.app-sidebar-user-name { font-size: 13px; font-weight: 600; color: var(--c-text); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.app-sidebar-user-type { font-size: 11.5px; color: var(--c-text-muted); text-transform: capitalize; margin-top: 1px; }

/* Nav links */
.app-sidebar-nav  { flex: 1; padding: 8px 8px 0; }
.app-sidebar-link {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 10px;
    border-radius: var(--r-md);
    margin-bottom: 2px;
    font-size: 13.5px;
    font-weight: 500;
    color: var(--c-text-3);
    text-decoration: none;
    transition: background 0.1s, color 0.1s;
}
.app-sidebar-link:hover  { background: var(--c-border-light); color: var(--c-text); }
.app-sidebar-link.active { background: var(--c-primary-light); color: var(--c-primary); }
.app-sidebar-icon {
    width: 24px; height: 24px;
    display: flex; align-items: center; justify-content: center;
    flex-shrink: 0;
    border-radius: 6px;
    background: rgba(0,0,0,0.03);
    transition: background 0.1s;
}
.app-sidebar-link.active .app-sidebar-icon { background: rgba(99,102,241,0.12); color: var(--c-primary); }

/* Footer / sign-out */
.app-sidebar-footer { padding: 10px 8px; border-top: 1px solid var(--c-border-light); flex-shrink: 0; }
.app-sidebar-signout {
    display: flex;
    align-items: center;
    gap: 8px;
    width: 100%;
    padding: 8px 10px;
    border-radius: var(--r-md);
    font-size: 13.5px; font-weight: 500;
    color: var(--c-text-3);
    background: none; border: none;
    cursor: pointer;
    transition: background 0.1s, color 0.1s;
    font-family: 'DM Sans', sans-serif;
    text-align: left;
}
.app-sidebar-signout:hover { background: var(--c-danger-light); color: var(--c-danger); }

/* Drawer overlay (mobile) */
.app-sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.4);
    z-index: 250;
    animation: sb-fade-in 0.2s ease;
}
.app-sidebar-overlay.open { display: block; }
@keyframes sb-fade-in { from { opacity: 0; } to { opacity: 1; } }

/* ── Page shell ───────────────────────────────────────────── */
.app-page{max-width:900px;margin:0 auto;padding:var(--sp-4) var(--sp-3);}
.app-page-title{font-size:var(--t-xl);font-weight:700;color:var(--c-text);letter-spacing:-.03em;margin-bottom:4px;}
.app-page-sub{font-size:var(--t-base);color:var(--c-text-muted);margin-bottom:var(--sp-3);}
.app-page-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:var(--sp-3);}
.app-form-wrap{max-width:520px;}

/* ── Grid helpers ─────────────────────────────────────────── */
.app-grid-2{display:grid;grid-template-columns:1fr 1fr;gap:var(--sp-2);align-items:start;}
.app-grid-3-2{display:grid;grid-template-columns:minmax(0,3fr) minmax(0,2fr);gap:var(--sp-2);align-items:start;}
.app-card-list{display:grid;gap:10px;}

/* ── Cards ────────────────────────────────────────────────── */
.app-card{background:var(--c-white);border-radius:var(--r-lg);border:1px solid var(--c-border);margin-bottom:var(--sp-2);overflow:hidden;}
.app-card-flush{margin-bottom:0;}
.app-card-header{padding:var(--sp-2) 20px;border-bottom:1px solid var(--c-border-light);display:flex;align-items:center;justify-content:space-between;}
.app-card-title{font-size:var(--t-md);font-weight:600;color:var(--c-text);}
.app-card-subtitle{font-size:12.5px;color:var(--c-text-muted);margin-top:2px;}
.app-card-body{padding:var(--sp-3) 20px;}
.app-card-body-sm{padding:var(--sp-2) 20px;}
.app-card-footer{padding:var(--sp-2) 20px;border-top:1px solid var(--c-border-light);}

/* ── Buttons ──────────────────────────────────────────────── */
.app-btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:7px 14px;border-radius:var(--r-md);font-size:14px;font-weight:500;text-decoration:none;border:none;cursor:pointer;transition:all .12s;font-family:'DM Sans',sans-serif;line-height:1;}
.app-btn-primary{background:var(--c-primary);color:var(--c-white);}
.app-btn-primary:hover{background:var(--c-primary-dark);}
.app-btn-secondary{background:var(--c-white);border:1px solid var(--c-border);color:var(--c-text-2);}
.app-btn-secondary:hover{background:#f9fafb;}
.app-btn-ghost{background:none;border:1px solid var(--c-border);color:var(--c-text-2);}
.app-btn-ghost:hover{background:#f9fafb;}
.app-btn-danger{background:none;border:1px solid var(--c-danger-border);color:var(--c-danger);}
.app-btn-danger:hover{background:var(--c-danger-light);}
.app-btn-sm{padding:4px 10px;font-size:12px;}
.app-btn-lg{padding:10px 24px;font-size:var(--t-md);}
.app-btn-full{width:100%;}
.app-btn-link{background:none;border:none;color:var(--c-primary);font-size:var(--t-sm);text-decoration:none;cursor:pointer;}

/* ── Forms ────────────────────────────────────────────────── */
.form-group{margin-bottom:var(--sp-2);}
.form-group-sm{margin-bottom:10px;}
.form-label{display:block;font-size:14px;font-weight:500;color:var(--c-text-2);margin-bottom:var(--sp-1);}
.form-label-required::after{content:' *';color:var(--c-danger);}
.form-hint{font-size:var(--t-xs);color:var(--c-text-muted);margin-top:4px;}
.form-actions{display:flex;gap:var(--sp-1);margin-top:var(--sp-3);}
.form-error-msg{font-size:var(--t-xs);color:var(--c-danger);margin-top:4px;}
.form-input,.form-select,.form-textarea{width:100%;padding:9px 13px;border-radius:var(--r-md);border:1px solid var(--c-border);font-size:var(--t-md);color:var(--c-text);background:var(--c-white);outline:none;transition:border-color .15s,box-shadow .15s;font-family:'DM Sans',sans-serif;}
.form-input:focus,.form-select:focus,.form-textarea:focus{border-color:var(--c-primary);box-shadow:0 0 0 3px rgba(99,102,241,.1);}
.form-input::placeholder,.form-textarea::placeholder{color:#d1d5db;}
.form-textarea{resize:vertical;min-height:80px;}
.form-select{cursor:pointer;}
.form-datepicker-wrap{position:relative;}
.form-datepicker-input{cursor:pointer;padding-right:36px!important;}
.form-datepicker-clear{position:absolute;right:10px;top:50%;transform:translateY(-50%);background:none;border:none;color:var(--c-text-muted);cursor:pointer;font-size:16px;line-height:1;padding:2px 4px;display:none;}
.form-datepicker-clear:hover{color:var(--c-text);}
.form-wrap-sm{max-width:400px;}
.form-wrap-md{max-width:520px;}
.form-wrap-lg{max-width:680px;}

/* ── Alerts ───────────────────────────────────────────────── */
.app-alert{padding:12px var(--sp-2);border-radius:var(--r-md);font-size:14px;font-weight:500;margin-bottom:var(--sp-2);display:flex;align-items:center;gap:var(--sp-1);}
.app-alert-success{background:var(--c-success-light);color:var(--c-success-text);border:1px solid var(--c-success-border);}
.app-alert-danger{background:var(--c-danger-light);color:var(--c-danger-text);border:1px solid var(--c-danger-border);}
.app-alert-info{background:var(--c-primary-light);color:var(--c-primary-deep);border:1px solid var(--c-primary-border);}
.app-alert-warning{background:var(--c-warning-light);color:var(--c-warning-text);border:1px solid #fcd34d;}

/* ── Badges ───────────────────────────────────────────────── */
.badge{display:inline-flex;align-items:center;padding:2px 9px;border-radius:var(--r-pill);font-size:var(--t-xs);font-weight:600;text-transform:capitalize;}
.badge-primary{background:var(--c-primary-light);color:var(--c-primary);}
.badge-success{background:rgba(16,185,129,.1);color:var(--c-success-text);}
.badge-warning{background:var(--c-warning-light);color:var(--c-warning-text);}
.badge-danger{background:var(--c-danger-light);color:var(--c-danger);}
.badge-neutral{background:var(--c-border-light);color:var(--c-text-3);}
.badge-parent{background:rgba(16,185,129,.1);color:var(--c-success-text);}
.badge-child{background:rgba(99,102,241,.1);color:#4338ca;}
.badge-tutor{background:var(--c-warning-light);color:var(--c-warning-text);}
.badge-pending{background:var(--c-border-light);color:var(--c-text-3);}
.badge-in-progress{background:var(--c-warning-light);color:var(--c-warning-text);}
.badge-completed{background:rgba(16,185,129,.1);color:var(--c-success-text);}

/* ── Tables ───────────────────────────────────────────────── */
.app-table{width:100%;border-collapse:collapse;}
.app-table-th{padding:10px 20px;text-align:left;font-size:var(--t-xs);color:var(--c-text-muted);font-weight:600;letter-spacing:.04em;text-transform:uppercase;border-bottom:1px solid var(--c-border-light);}
.app-table-th-center{padding:10px 20px;text-align:center;font-size:var(--t-xs);color:var(--c-text-muted);font-weight:600;letter-spacing:.04em;text-transform:uppercase;border-bottom:1px solid var(--c-border-light);}
.app-table-th-empty{padding:10px 20px;border-bottom:1px solid var(--c-border-light);}
.app-table-row{border-bottom:1px solid var(--c-row-border);}
.app-table-row:last-child{border-bottom:none;}
.app-table-td{padding:12px 20px;font-size:14px;color:var(--c-text-2);}
.app-table-td-primary{padding:12px 20px;font-size:14px;font-weight:600;color:var(--c-text);}
.app-table-td-muted{padding:12px 20px;font-size:var(--t-sm);color:var(--c-text-muted);}
.app-table-td-actions{padding:12px 20px;text-align:right;white-space:nowrap;}
.app-table-td-badge{padding:12px 20px;}
.app-table-td-center{padding:12px 20px;text-align:center;}
.app-table-td-word{padding:11px 20px;}

/* ── Word list rows ───────────────────────────────────────── */
.word-list-row{display:flex;align-items:center;justify-content:space-between;padding:10px 20px;border-bottom:1px solid var(--c-row-border);}
.word-list-row:last-child{border-bottom:none;}
.word-list-row-name{font-size:14px;font-weight:600;color:var(--c-text);}
.word-list-row-def{font-size:var(--t-xs);color:var(--c-text-muted);margin-top:2px;}
.word-list-remove{background:none;border:none;color:var(--c-text-muted);cursor:pointer;font-size:12px;padding:3px 6px;border-radius:var(--r-sm);transition:color .12s;}
.word-list-remove:hover{color:var(--c-danger);}

/* ── User list rows ───────────────────────────────────────── */
.app-user-list{padding:4px 0;}
.app-user-row{display:flex;align-items:center;justify-content:space-between;padding:10px 20px;border-bottom:1px solid #f7f7f9;text-decoration:none;transition:background .08s;}
.app-user-row:hover{background:#fafafa;}
.app-user-row:last-child{border-bottom:none;}
.app-user-row-static{cursor:default;}
.app-user-row-no-border{border-bottom:none!important;}
.app-user-avatar{width:32px;height:32px;border-radius:var(--r-md);display:flex;align-items:center;justify-content:center;font-size:13px;font-weight:700;color:var(--c-white);flex-shrink:0;}
.app-user-info{flex:1;margin-left:10px;}
.app-user-name{font-size:14px;font-weight:600;color:var(--c-text);}
.app-user-email{font-size:var(--t-xs);color:var(--c-text-muted);}
.avatar-primary{background:var(--c-primary);}
.avatar-success{background:var(--c-success);}
.avatar-warning{background:var(--c-warning);}
.avatar-purple{background:#8b5cf6;}
.row-chevron{color:#d1d5db;flex-shrink:0;}
.child-row-wrap{border-bottom:1px solid #f7f7f9;}
.child-row-vocab-strip{padding:8px 20px 12px;}

/* ── Profile rows ─────────────────────────────────────────── */
.profile-row{display:flex;align-items:center;justify-content:space-between;padding:10px 0;border-bottom:1px solid var(--c-border-light);}
.profile-row:last-child{border-bottom:none;}
.profile-label{font-size:var(--t-sm);color:var(--c-text-muted);font-weight:500;}
.profile-value{font-size:14px;color:var(--c-text-2);font-weight:500;text-align:right;}
.profile-bio{margin-top:var(--sp-2);}
.profile-bio-label{font-size:var(--t-sm);color:var(--c-text-muted);font-weight:500;margin-bottom:6px;}
.profile-bio-text{font-size:14px;color:var(--c-text-2);line-height:1.6;}

/* ── Empty states ─────────────────────────────────────────── */
.app-empty{padding:var(--sp-5) 20px;text-align:center;}
.app-empty-sm{padding:var(--sp-3) 20px;text-align:center;}
.app-empty-icon{font-size:32px;margin-bottom:var(--sp-2);}
.app-empty-title{font-size:var(--t-md);font-weight:600;color:var(--c-text-2);margin-bottom:4px;}
.app-empty-text{font-size:14px;color:var(--c-text-muted);}

/* ── Misc helpers ─────────────────────────────────────────── */
.u-hidden{display:none!important;}
.app-section-label{font-size:12px;font-weight:600;color:var(--c-text-muted);letter-spacing:.05em;text-transform:uppercase;margin-bottom:var(--sp-1);}
.back-row{margin-bottom:var(--sp-2);}
.nav-quick-links{display:flex;gap:var(--sp-1);flex-wrap:wrap;margin-top:var(--sp-2);}
.text-warning{color:var(--c-warning);font-weight:500;}
.text-muted{color:var(--c-text-muted);}
.text-primary{color:var(--c-primary);}

/* ── Pending assignment banner ────────────────────────────── */
.pending-banner{background:var(--c-primary-light);border:1px solid var(--c-primary-border);border-radius:var(--r-lg);padding:var(--sp-2) 20px;margin-bottom:var(--sp-3);display:flex;align-items:center;justify-content:space-between;gap:var(--sp-2);}
.pending-banner-left{display:flex;align-items:center;gap:12px;}
.pending-banner-icon{font-size:24px;flex-shrink:0;}
.pending-banner-title{font-size:var(--t-md);font-weight:700;color:var(--c-primary-deep);}
.pending-banner-sub{font-size:var(--t-sm);color:var(--c-primary);margin-top:2px;}

/* ── Score display ────────────────────────────────────────── */
.score-card-body{text-align:center;padding:var(--sp-5) 20px;}
.score-hero{font-size:64px;font-weight:800;letter-spacing:-.04em;line-height:1;}
.score-hero-sm{font-size:48px;font-weight:800;letter-spacing:-.04em;line-height:1;}
.score-msg{font-size:16px;font-weight:600;color:var(--c-text-2);margin:8px 0 4px;}
.score-sub{font-size:var(--t-base);color:var(--c-text-muted);}
.score-label{font-size:12px;color:var(--c-text-muted);font-weight:500;margin-top:4px;text-transform:uppercase;letter-spacing:.04em;}
.score-high{color:var(--c-success);}
.score-mid{color:var(--c-primary);}
.score-low{color:var(--c-warning);}
.score-fail{color:var(--c-danger);}
.score-summary{display:flex;align-items:center;gap:32px;}
.score-summary-icon{flex-shrink:0;text-align:center;}
.score-summary-info{flex:1;}

/* ── Vocab-specific ───────────────────────────────────────── */
.vocab-word-title{font-size:var(--t-lg);font-weight:700;color:var(--c-primary);letter-spacing:-.02em;margin-bottom:var(--sp-1);}
.vocab-definition{font-size:var(--t-base);color:var(--c-text-2);margin-bottom:4px;}
.vocab-example{font-size:var(--t-sm);color:var(--c-text-muted);font-style:italic;}
.vocab-counter{font-size:11px;font-weight:700;color:var(--c-text-muted);background:var(--c-border-light);padding:2px 7px;border-radius:var(--r-sm);display:inline-block;margin-bottom:var(--sp-1);}
.vocab-answer-input{width:100%;padding:10px 14px;border-radius:var(--r-md);border:2px solid var(--c-border);font-size:15px;font-weight:500;outline:none;font-family:'DM Sans',sans-serif;transition:border-color .15s,box-shadow .15s;}
.vocab-answer-input:focus{border-color:var(--c-primary);box-shadow:0 0 0 3px rgba(99,102,241,.1);}
.vocab-study-count{font-size:var(--t-sm);color:var(--c-text-muted);}

/* Word breakdown rows (results pages) */
.word-breakdown-row{padding:14px 20px;border-bottom:1px solid var(--c-row-border);display:flex;align-items:flex-start;justify-content:space-between;gap:var(--sp-2);}
.word-breakdown-row:last-child{border-bottom:none;}
.word-breakdown-info{flex:1;}
.word-breakdown-name{font-size:14px;font-weight:700;color:var(--c-text);margin-bottom:2px;}
.word-breakdown-def{font-size:12.5px;color:var(--c-text-muted);}
.word-breakdown-answer{margin-top:6px;font-size:var(--t-sm);}
.word-breakdown-you{color:var(--c-text-muted);}
.word-breakdown-icon{flex-shrink:0;font-size:20px;}
.answer-correct{color:var(--c-success);font-weight:600;}
.answer-wrong{color:var(--c-danger);font-weight:600;}
.answer-empty{color:var(--c-text-muted);font-style:italic;}
.td-answer-correct{color:var(--c-text-2);}
.td-answer-wrong{color:var(--c-danger);}

/* ── Auth pages ───────────────────────────────────────────── */
.auth-body{background:var(--c-bg);display:flex;align-items:center;justify-content:center;min-height:100vh;}
.auth-wrap{background:var(--c-white);border-radius:var(--r-xl);border:1px solid var(--c-border);box-shadow:0 8px 32px rgba(0,0,0,.08);padding:var(--sp-5);width:100%;max-width:400px;}
.auth-logo {
    width: 88px;
    height: 88px;
    margin: 0 auto 24px;
    border-radius: 20px;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
}

.auth-logo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}
.auth-title{font-size:20px;font-weight:700;color:var(--c-text);letter-spacing:-.03em;margin-bottom:4px;}
.auth-sub{font-size:var(--t-base);color:var(--c-text-muted);margin-bottom:28px;line-height:1.6;}
.auth-btn{width:100%;padding:10px;background:var(--c-primary);color:var(--c-white);border:none;border-radius:var(--r-md);font-size:var(--t-md);font-weight:600;cursor:pointer;margin-top:var(--sp-1);transition:background .15s;font-family:'DM Sans',sans-serif;letter-spacing:-.01em;}
.auth-btn:hover{background:var(--c-primary-dark);}
.auth-link{color:var(--c-primary);font-size:14px;text-decoration:none;display:block;text-align:center;margin-top:var(--sp-2);}
.auth-note{margin-top:var(--sp-3);font-size:12px;color:#d1d5db;text-align:center;}
.auth-error{background:var(--c-danger-light);border:1px solid var(--c-danger-border);color:#dc2626;border-radius:var(--r-md);padding:10px 14px;font-size:14px;font-weight:500;margin-bottom:var(--sp-2);}
.auth-info{background:var(--c-success-light);border:1px solid var(--c-success-border);border-radius:var(--r-md);padding:14px var(--sp-2);font-size:14px;color:var(--c-success-text);line-height:1.6;margin-bottom:var(--sp-3);}
.auth-denied-wrap{text-align:center;max-width:360px;padding:var(--sp-5) var(--sp-3);}
.auth-denied-icon{width:64px;height:64px;background:var(--c-danger-light);border-radius:var(--r-xl);display:flex;align-items:center;justify-content:center;margin:0 auto var(--sp-3);}

/* ── Flatpickr theme ──────────────────────────────────────── */
.flatpickr-calendar{font-family:'DM Sans',sans-serif;border-radius:var(--r-lg);box-shadow:0 8px 32px rgba(0,0,0,.12);border:1px solid var(--c-border);}
.flatpickr-day.selected,.flatpickr-day.selected:hover{background:var(--c-primary);border-color:var(--c-primary);}
.flatpickr-day:hover{background:var(--c-primary-light);}
.flatpickr-months .flatpickr-month{background:var(--c-primary);border-radius:11px 11px 0 0;}
.flatpickr-current-month,.flatpickr-monthDropdown-months,.flatpickr-current-month input.cur-year{color:var(--c-white);}
.flatpickr-months .flatpickr-prev-month svg,.flatpickr-months .flatpickr-next-month svg{fill:var(--c-white);}
.flatpickr-weekday{color:var(--c-text-muted);font-weight:600;font-size:11px;}
.flatpickr-day.today{border-color:var(--c-primary);}

/* ── Responsive ───────────────────────────────────────────── */

/* Tablet / mobile: sidebar becomes a drawer (≤ 768px) */
@media (max-width: 768px) {
    /* Show mobile top bar */
    .app-topbar {
        display: flex;
        align-items: center;
        gap: 12px;
        height: 56px;
        padding: 0 var(--sp-2);
        background: var(--c-white);
        border-bottom: 1px solid var(--c-border);
        position: sticky;
        top: 0;
        z-index: 200;
    }
    .app-topbar-toggle {
        width: 36px; height: 36px;
        display: flex; align-items: center; justify-content: center;
        background: none;
        border: 1px solid var(--c-border);
        border-radius: var(--r-md);
        color: var(--c-text-3);
        cursor: pointer;
        flex-shrink: 0;
        transition: background 0.1s;
    }
    .app-topbar-toggle:hover { background: var(--c-border-light); }
    .app-topbar-brand {
        display: flex; align-items: center; gap: 8px;
        text-decoration: none;
    }
    .app-topbar-logo  { width: 32px; height: 32px; object-fit: contain; }
    .app-topbar-title { font-size: 16px; font-weight: 700; color: var(--c-text); letter-spacing: -0.02em; }

    /* Sidebar: off-screen by default, slides in when .open */
    .app-sidebar {
        transform: translateX(-100%);
        transition: transform 0.28s ease;
        z-index: 300;
        width: 240px;
    }
    .app-sidebar.open { transform: translateX(0); }

    /* Prevent body scroll when drawer is open */
    body.sidebar-open { overflow: hidden; }

    /* Wrapper: full viewport width */
    .app-wrapper { margin-left: 0; }

    /* Page padding */
    .app-page { padding: var(--sp-3) var(--sp-2); }

    /* Grids collapse to single column */
    .app-grid-2, .app-grid-3-2 { grid-template-columns: 1fr; }

    /* Score / pending banner */
    .score-summary  { flex-direction: column; align-items: flex-start; gap: var(--sp-2); }
    .pending-banner { flex-direction: column; align-items: flex-start; }

    /* Assignment card: buttons wrap below title */
    .app-card-header { flex-wrap: wrap; gap: 10px; align-items: flex-start; }
    .app-card-header .form-actions { margin-top: 0; }
}

/* Small phones (≤ 480px) */
@media (max-width: 480px) {
    .app-topbar-title  { font-size: 15px; }
    .app-page          { padding: var(--sp-2); }
    .app-page-title    { font-size: 22px; }

    /* Study / Take Test buttons fill the row */
    .app-card-header .form-actions { width: 100%; flex-wrap: wrap; }
    .app-card-header .form-actions .app-btn { flex: 1; justify-content: center; }

    /* Completed-assignments table: horizontal scroll */
    .app-card .app-table { display: block; overflow-x: auto; -webkit-overflow-scrolling: touch; }
}

/* ── Inline form (delete buttons inline with other elements) ─ */
.form-inline { display: inline; }

/* ── Assignment Dashboard (6.1D) ─────────────────────────────────────────── */
.vocab-dashboard-cards   { display: flex; gap: var(--sp-2); flex-wrap: wrap; margin-bottom: var(--sp-3); }
.vocab-stat-card         { background: var(--c-white); border: 1px solid var(--c-border); border-radius: var(--r-lg); padding: var(--sp-2) var(--sp-3); min-width: 120px; text-align: center; }
.vocab-stat-number       { font-size: 28px; font-weight: 700; color: var(--c-text); letter-spacing: -.03em; }
.vocab-stat-label        { font-size: var(--t-xs); color: var(--c-text-muted); font-weight: 600; text-transform: uppercase; letter-spacing: .04em; margin-top: 4px; }
.vocab-stat-pending      { border-left: 3px solid var(--c-text-muted); }
.vocab-stat-inprogress   { border-left: 3px solid var(--c-warning); }
.vocab-stat-completed    { border-left: 3px solid var(--c-success); }
.vocab-stat-overdue      { border-left: 3px solid var(--c-danger); }
.vocab-stat-overdue .vocab-stat-number { color: var(--c-danger); }

/* Progress bar */
.vocab-progress-bar-wrap { background: var(--c-border-light); border-radius: 4px; height: 6px; width: 80px; overflow: hidden; display: inline-block; vertical-align: middle; margin-right: 6px; }
.vocab-progress-bar      { height: 100%; width: 0%; background: var(--c-primary); border-radius: 4px; transition: width 0.3s; }
.vocab-progress-full     { background: var(--c-success); }
.vocab-progress-mid      { background: var(--c-warning); }
.vocab-progress-label    { font-size: var(--t-xs); color: var(--c-text-muted); vertical-align: middle; }

/* ── Vocabulary sub-navigation (6.1D) ────────────────────── */
.vocab-subnav {
    display: flex;
    gap: 2px;
    margin-bottom: var(--sp-3);
    border-bottom: 1px solid var(--c-border);
    padding-bottom: 0;
}
.vocab-subnav-link {
    font-size: 14px;
    font-weight: 500;
    color: var(--c-text-3);
    text-decoration: none;
    padding: 8px 14px;
    border-radius: var(--r-sm) var(--r-sm) 0 0;
    border-bottom: 2px solid transparent;
    transition: color .12s, border-color .12s;
    margin-bottom: -1px;
}
.vocab-subnav-link:hover {
    color: var(--c-text);
    background: var(--c-border-light);
}
.vocab-subnav-link--active {
    color: var(--c-primary);
    border-bottom-color: var(--c-primary);
    font-weight: 600;
}

/* ── Table layout fix (6.1D) ─────────────────────────────── */
.app-table-fixed { table-layout: fixed; width: 100%; }

/* ── Dashboard table column widths ───────────────────────── */
.vocab-col-student   { width: 14%; }
.vocab-col-list      { width: 14%; }
.vocab-col-date      { width: 10%; }
.vocab-col-status    { width: 10%; }
.vocab-col-progress  { width: 12%; }
.vocab-col-activity  { width: 14%; }
.vocab-col-score     { width: 8%; }
.vocab-col-actions   { width: 170px; min-width: 170px; }