@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap');

:root {
  --bg-main:      #0a0a0a;
  --bg-surface:   #121212;
  --bg-input:     #171717;
  --bg-hover:     #1e1e1e;
  
  --border:       #27272a;
  --border-focus: #52525b;
  
  --text-main:    #f4f4f5;
  --text-dim:     #a1a1aa;
  
  --primary:      #ffffff;
  --primary-text: #000000;
  
  --accent:       #3b82f6;
  
  --success:      #10b981;
  --error:        #ef4444;

  --font: 'Inter', -apple-system, sans-serif;
  --ease: 0.2s ease-out;
  
  --space-xs:  0.5rem;
  --space-sm:  1rem;
  --space-md:  1.5rem;
  --space-lg:  2.5rem;
  --space-xl:  4rem;
  
  --radius:    12px;
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes pulseGlow {
  0% { box-shadow: 0 0 0 0 rgba(255,255,255,0.1); }
  70% { box-shadow: 0 0 0 10px rgba(255,255,255,0); }
  100% { box-shadow: 0 0 0 0 rgba(255,255,255,0); }
}

html { scroll-behavior: smooth; }
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  color-scheme: dark;
  font-family: var(--font);
  background-color: var(--bg-main);
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--text-dim); text-decoration: none; transition: color var(--ease); }
a:hover { color: var(--text-main); }

button, input, select, textarea { 
  font-family: inherit; 
  font-size: 1rem;
}

.hidden { display: none !important; }
.flex { display: flex; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.w-full { width: 100%; }

.page-auth {
  display: flex; align-items: center; justify-content: center;
  min-height: 100vh; padding: var(--space-md);
  background: radial-gradient(circle at top right, rgba(0, 123, 255, 0.1), transparent 40%),
              radial-gradient(circle at bottom left, rgba(0, 168, 255, 0.05), transparent 40%),
              var(--bg-main);
  position: relative;
}

.auth-card {
  width: 100%; max-width: 440px; margin: 0 auto;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  padding: var(--space-xl) var(--space-lg);
  border-radius: var(--radius-lg);
  box-shadow: 0 24px 48px rgba(0,0,0,0.6);
  z-index: 10;
  animation: fadeInUp 0.5s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.auth-logo { text-align: center; margin-bottom: var(--space-lg); }
.logo-icon {
  width: 48px; height: 48px; margin: 0 auto var(--space-sm);
  background: var(--text-main); color: var(--bg-main);
  border-radius: 12px; display: flex; align-items: center; justify-content: center;
}
.auth-title { font-size: 1.5rem; font-weight: 600; margin-bottom: var(--space-xs); letter-spacing: -0.02em; }
.auth-sub { color: var(--text-dim); font-size: 0.95rem; }

.form-group { margin-bottom: var(--space-md); }

.form-label {
  display: block; font-size: 0.85rem; font-weight: 500;
  color: var(--text-dim); margin-bottom: 0.6rem;
}
.form-label.required::after { content: ' *'; color: var(--text-dim); }

.input-wrap { position: relative; display: flex; align-items: center; }

.form-input {
  width: 100%;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-main);
  padding: 1rem 1.25rem 1rem 2.85rem; /* Space for the icon */
  transition: all 0.3s cubic-bezier(0.2, 0.8, 0.2, 1);
  outline: none;
}
.form-input.no-icon, select.form-input { 
  padding-left: 1.25rem; 
}

.form-input:hover { border-color: #3f3f46; transform: translateY(-1px); }
.form-input:focus {
  border-color: var(--border-focus);
  background: #1f1f22;
  transform: translateY(-2px);
  box-shadow: 0 8px 16px rgba(0,0,0,0.4);
  z-index: 5;
  position: relative;
}
.form-input::placeholder { color: #52525b; transition: opacity 0.3s; }
.form-input:focus::placeholder { opacity: 0.5; }

select.form-input {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  padding-right: 3rem;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%23ffffff' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1.25rem center;
  background-size: 16px;
  cursor: pointer;
}
select.form-input:hover {
  background-position: right 1rem center;
}
select.form-input:focus {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%23ffffff' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M18 15l-6-6-6 6'/%3E%3C/svg%3E");
}
select.form-input option {
  background-color: var(--bg-surface);
  color: var(--text-main);
}
.input-toggle {
  position: absolute; right: 1rem; top: 50%; transform: translateY(-50%);
  background: none; border: none; color: var(--text-dim); 
  cursor: pointer; padding: 0.25rem; z-index: 10;
}
.input-toggle:hover { color: var(--text-main); }
.input-toggle svg { width: 1.25rem; height: 1.25rem; }

.input-icon { 
  position: absolute; left: 1.1rem; top: 50%; transform: translateY(-50%);
  color: var(--text-dim); width: 1.2rem; height: 1.2rem;
  z-index: 10; pointer-events: none; transition: color 0.3s;
}
.form-input:focus ~ .input-icon, .form-input:focus + .input-icon {
  color: var(--text-main);
}

.form-row { display: grid; gap: var(--space-md); }
@media(min-width: 640px) { .form-row.cols-2 { grid-template-columns: 1fr 1fr; } }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 0.5rem;
  padding: 1rem 1.5rem;
  font-size: 1rem; font-weight: 600;
  border-radius: var(--radius);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.btn-full { width: 100%; }

.btn-primary {
  background: var(--primary);
  color: var(--primary-text);
  box-shadow: 0 4px 14px 0 rgba(255, 255, 255, 0.1);
}
.btn-primary:hover { 
  transform: translateY(-4px) scale(1.02);
  box-shadow: 0 6px 20px rgba(255,255,255,0.23); 
}
.btn-primary:active { transform: scale(0.96); }

.btn-secondary {
  background: var(--bg-hover);
  color: var(--text-main);
  border-color: var(--border);
}
.btn-secondary:hover { 
  background: #27272a; 
  transform: translateY(-2px);
  border-color: var(--text-dim);
}
.btn-secondary:active { transform: scale(0.96); }

.btn-danger {
  background: transparent;
  color: var(--error);
  border-color: rgba(239, 68, 68, 0.3);
}
.btn-danger:hover { background: rgba(239, 68, 68, 0.1); }

.btn-icon { padding: 0.5rem; border-radius: var(--radius); }
.btn-sm { padding: 0.5rem 1rem; font-size: 0.85rem; }

.dash-layout { display: flex; flex-direction: column; min-height: 100vh; }

.app-sidebar { display: none; }
.dash-header-mobile {
  position: sticky; top: 0; z-index: 100;
  background: var(--bg-main); border-bottom: 1px solid var(--border);
  padding: var(--space-sm) var(--space-md);
  display: flex; align-items: center; justify-content: space-between;
}

@media(min-width: 1024px) {
  .dash-layout { flex-direction: row; }
  .dash-header-mobile { display: none; }
  
  .app-sidebar {
    display: flex; flex-direction: column;
    width: 280px; background: var(--bg-surface);
    border-right: 1px solid var(--border);
    position: sticky; top: 0; height: 100vh;
    padding: var(--space-lg) var(--space-md);
  }
  .sidebar-header { margin-bottom: var(--space-xl); display: flex; align-items: center; gap: var(--space-sm); font-size: 1.1rem; font-weight: 600; }
  .sidebar-header .logo-icon { width: 32px; height: 32px; background: var(--text-main); color: var(--bg-main); border-radius: 6px; display: flex; align-items: center; justify-content: center; }
  
  .sidebar-nav { display: flex; flex-direction: column; gap: var(--space-xs); flex: 1; }
  .sidebar-link {
    display: flex; align-items: center; gap: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
    background: transparent; border: none; border-radius: var(--radius);
    color: var(--text-dim); font-size: 0.95rem; font-weight: 500;
    cursor: pointer; transition: all 0.2s; text-align: left;
  }
  .sidebar-link.active { background: #27272a; color: var(--text-main); font-weight: 600; }
  .sidebar-link:hover:not(.active) { background: var(--bg-hover); color: var(--text-main); }
  
  .sidebar-footer {
    display: flex; align-items: center; justify-content: space-between;
    padding-top: var(--space-lg); border-top: 1px solid var(--border);
    margin-top: auto;
  }
  .sidebar-footer .btn-icon {
    flex-shrink: 0;
    z-index: 10;
    position: relative;
  }
}

.header-logo { display: flex; align-items: center; gap: 0.75rem; }
.header-brand { font-size: 1rem; font-weight: 600; }
.header-brand span { font-size: 0.75rem; color: var(--text-dim); display: block; font-weight: 400; }

.header-user { display: flex; align-items: center; gap: var(--space-sm); }
.user-avatar {
  width: 36px; height: 36px; border-radius: 50%;
  background: var(--bg-hover); border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  font-weight: 600; font-size: 0.85rem; color: var(--text-main);
}
.user-info { display: none; }
@media(min-width: 640px) {
  .user-info { display: block; text-align: right; line-height: 1.2; }
  .user-name { font-size: 0.9rem; font-weight: 500; color: var(--text-main); }
  .user-role { font-size: 0.75rem; color: var(--text-dim); }
}

.dash-main { 
  flex: 1; width: 100%; max-width: 1000px; 
  padding: var(--space-lg) var(--space-sm) 100px; 
  animation: fadeInUp 0.5s ease-out forwards;
}
@media(min-width: 1024px) { 
  .dash-main { padding: var(--space-xl); margin: 0; max-width: 1200px;} 
}

/* ── Bottom Nav (Mobile Only) ──────────────────────────────────── */
.bottom-nav {
  display: flex; position: fixed; bottom: 0; left: 0; right: 0; z-index: 100;
  background: var(--bg-main); border-top: 1px solid var(--border);
  padding: 0.75rem 0 calc(0.75rem + env(safe-area-inset-bottom));
}
.nav-item {
  flex: 1; display: flex; flex-direction: column; align-items: center; gap: 0.3rem;
  background: none; border: none; color: var(--text-dim);
  font-size: 0.7rem; font-weight: 500; cursor: pointer;
  transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.nav-item.active { color: var(--text-main); transform: translateY(-3px); }
.nav-item svg { width: 22px; height: 22px; transition: transform 0.3s; }
.nav-item.active svg { transform: scale(1.15); filter: drop-shadow(0 2px 4px rgba(255,255,255,0.2)); }
@media(min-width: 640px) { .bottom-nav { display: none; } }

/* ── Tabs (Mobile Only Now) ────────────────────────── */
.tabs {
  display: flex; gap: var(--space-md); margin-bottom: var(--space-lg);
  border-bottom: 1px solid var(--border);
}
@media(min-width: 1024px) {
  .tabs { display: none; }
}
.tab-btn {
  padding: 0 0 var(--space-sm) 0; border: none; background: transparent;
  color: var(--text-dim); font-size: 1rem; font-weight: 500;
  cursor: pointer; position: relative; transition: color 0.3s;
}
.tab-btn.active { color: var(--text-main); }
.tab-btn::after {
  content: ''; position: absolute; bottom: -1px; left: 0; right: 0;
  height: 2px; background: var(--text-main);
  transform: scaleX(0); transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  transform-origin: center;
}
.tab-btn.active::after { transform: scaleX(1); }
.tab-btn:hover:not(.active) { color: #d4d4d8; }

.stats-grid { display: grid; gap: var(--space-md); margin-bottom: var(--space-lg); }
@media(min-width: 640px) { .stats-grid { grid-template-columns: repeat(2, 1fr); } }

.stat-card {
  padding: var(--space-md);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-surface);
  transition: all 0.4s cubic-bezier(0.2, 0.8, 0.2, 1);
}
.stat-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 30px rgba(0,0,0,0.5);
  border-color: #3f3f46;
}
.stat-label { font-size: 0.85rem; color: var(--text-dim); margin-bottom: var(--space-sm); transition: color 0.3s; }
.stat-card:hover .stat-label { color: var(--text-main); }
.stat-value { font-size: 3rem; font-weight: 600; line-height: 1; margin-bottom: 0.5rem; letter-spacing: -1px; }
.stat-sub { font-size: 0.85rem; color: var(--text-dim); }

.lesson-card {
  padding: var(--space-md); margin-bottom: var(--space-sm);
  background: var(--bg-surface); border: 1px solid var(--border);
  border-radius: var(--radius);
  display: flex; flex-direction: column; gap: var(--space-sm);
  transition: all 0.3s ease;
  animation: fadeInUp 0.4s ease-out backwards;
}
.lesson-card:nth-child(2) { animation-delay: 0.1s; }
.lesson-card:nth-child(3) { animation-delay: 0.2s; }
.lesson-card:hover {
  transform: translateX(6px);
  border-color: #52525b;
  background: #18181b;
}
.lesson-card-head { display: flex; justify-content: space-between; align-items: flex-start; }
.lesson-student { font-size: 1.1rem; font-weight: 500; }

.badge {
  display: inline-flex; align-items: center; padding: 0.2rem 0.6rem;
  border-radius: 4px; font-size: 0.75rem; font-weight: 500;
  background: var(--bg-input); border: 1px solid var(--border); color: var(--text-dim);
}

.lesson-meta { display: flex; gap: var(--space-sm); align-items: center; flex-wrap: wrap; color: var(--text-dim); font-size: 0.85rem; }
.lesson-obs { margin-top: var(--space-xs); padding-top: var(--space-sm); border-top: 1px solid var(--border); color: var(--text-dim); font-size: 0.85rem; }

.report-grid { display: flex; flex-direction: column; gap: var(--space-sm); }
.report-card {
  display: flex; align-items: center; justify-content: space-between;
  padding: var(--space-md); background: var(--bg-surface);
  border: 1px solid var(--border); border-radius: var(--radius);
  cursor: pointer; transition: all 0.2s;
}
.report-card:hover {
  border-color: #52525b; background: #18181b; transform: translateX(4px);
}
.report-rank {
  font-weight: 700; color: var(--border-focus); margin-right: var(--space-md);
  font-size: 1.25rem; width: 24px; text-align: center;
}
.report-info { flex: 1; }
.report-name { font-weight: 600; font-size: 1.05rem; }
.report-email { font-size: 0.85rem; color: var(--text-dim); }
.report-count {
  font-size: 1.5rem; font-weight: 700; color: var(--text-main);
  text-align: right; line-height: 1;
}
.report-count small { display: block; font-size: 0.75rem; font-weight: 400; color: var(--text-dim); }

.table-wrap {
  width: 100%; overflow-x: auto;
  border: 1px solid var(--border); border-radius: var(--radius);
  background: var(--bg-surface);
}
table { width: 100%; border-collapse: collapse; min-width: 600px; text-align: left; }
th { 
  padding: var(--space-sm) var(--space-md); 
  font-size: 0.8rem; font-weight: 500; color: var(--text-dim); 
  border-bottom: 1px solid var(--border); 
}
td { 
  padding: var(--space-md); 
  font-size: 0.95rem; border-bottom: 1px solid var(--border); 
}
tr:last-child td { border-bottom: none; }

.filter-bar {
  display: flex; flex-wrap: wrap; gap: var(--space-md); align-items: flex-end;
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--border);
}
.filter-group { flex: 1; min-width: 140px; }

.modal-overlay {
  position: fixed; inset: 0; z-index: 200;
  background: rgba(0,0,0,0.7); backdrop-filter: blur(2px);
  display: flex; align-items: center; justify-content: center; padding: var(--space-sm);
}
.modal {
  width: 100%; max-width: 480px; max-height: 90vh; overflow-y: auto;
  background: var(--bg-main); border: 1px solid var(--border);
  border-radius: var(--radius);
}
.modal-header {
  padding: var(--space-md) var(--space-lg); border-bottom: 1px solid var(--border);
  display: flex; justify-content: space-between; align-items: center;
  position: sticky; top: 0; background: var(--bg-main); z-index: 10;
}
.modal-title { font-size: 1.1rem; font-weight: 500; }
.modal-close { background: none; border: none; color: var(--text-dim); cursor: pointer; padding: 0.25rem; }
.modal-body { padding: var(--space-lg); }
.modal-footer { padding: var(--space-md) var(--space-lg); border-top: 1px solid var(--border); display: flex; gap: var(--space-sm); }

.confirm-overlay {
  position: fixed; inset: 0; z-index: 300;
  background: rgba(0,0,0,0.8); backdrop-filter: blur(4px);
  display: flex; align-items: center; justify-content: center; padding: var(--space-md);
}
.confirm-box {
  width: 100%; max-width: 400px;
  background: var(--bg-surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: var(--space-lg);
  box-shadow: 0 24px 48px rgba(0,0,0,0.8);
  animation: fadeInUp 0.3s cubic-bezier(0.16, 1, 0.3, 1) forwards;
  text-align: center;
}
.confirm-title { font-size: 1.2rem; font-weight: 600; margin-bottom: var(--space-sm); color: var(--text-main); }
.confirm-msg { font-size: 0.95rem; color: var(--text-dim); margin-bottom: var(--space-lg); }
.confirm-actions { display: flex; gap: var(--space-sm); }
.confirm-actions .btn { flex: 1; }

.empty-state { text-align: center; padding: var(--space-xl) var(--space-md); }
.empty-state svg { width: 48px; height: 48px; color: var(--border); margin: 0 auto var(--space-md); }
.empty-state p { font-size: 1rem; color: var(--text-dim); }

.spinner {
  width: 18px; height: 18px; border: 2px solid var(--border);
  border-top-color: var(--text-main); border-radius: 50%;
  animation: spin 0.6s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.alert { padding: var(--space-sm) var(--space-md); border-radius: var(--radius); font-size: 0.9rem; margin-bottom: var(--space-md); border: 1px solid transparent; }
.alert-error { background: rgba(239, 68, 68, 0.1); border-color: rgba(239, 68, 68, 0.2); color: #fca5a5; }
.alert-success{ background: rgba(16, 185, 129, 0.1); border-color: rgba(16, 185, 129, 0.2); color: #86efac; }

#toast {
  position: fixed; bottom: 5rem; right: var(--space-md); z-index: 999;
  padding: var(--space-sm) var(--space-md); border: 1px solid var(--border);
  background: var(--bg-surface); border-radius: var(--radius);
  font-size: 0.9rem; font-weight: 500; box-shadow: 0 10px 30px rgba(0,0,0,0.5);
}
@media(min-width: 640px) { #toast { bottom: var(--space-md); } }