@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

/* ===== CSS VARIABLES ===== */
:root {
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --primary-light: #eef2ff;
    --primary-glow: rgba(79,70,229,0.15);
    --secondary: #7c3aed;
    --success: #10b981;
    --success-light: #ecfdf5;
    --danger: #ef4444;
    --danger-light: #fef2f2;
    --warning: #f59e0b;
    --warning-light: #fffbeb;
    --info: #06b6d4;
    --dark: #1e293b;
    --gray-50: #f8fafc;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-300: #cbd5e1;
    --gray-400: #94a3b8;
    --gray-500: #64748b;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1e293b;
    --gray-900: #0f172a;
    --bg: #f0f4ff;
    --card-bg: rgba(255,255,255,0.95);
    --text: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --sidebar-w: 260px;
    --radius-sm: 8px;
    --radius: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-full: 9999px;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
    --shadow: 0 4px 16px rgba(0,0,0,0.06);
    --shadow-lg: 0 12px 40px rgba(0,0,0,0.08);
    --shadow-glow: 0 0 20px var(--primary-glow);
    --ease: cubic-bezier(0.4,0,0.2,1);
    --transition: all 0.25s var(--ease);
}

/* ===== RESET & BASE ===== */
*,*::before,*::after { margin:0;padding:0;box-sizing:border-box; }
html { 
    scroll-behavior:smooth;
    -webkit-text-size-adjust:100%;
    font-size:16px; 
    overflow-x: hidden;
    width: 100%;
}
body {
    font-family:'Inter',system-ui,-apple-system,sans-serif;
    background:var(--bg);
    color:var(--text);
    line-height:1.6;
    overflow-x:hidden;
    width: 100%;
    -webkit-font-smoothing:antialiased;
    -moz-osx-font-smoothing:grayscale;
    position: relative;
}
img { max-width:100%;height:auto; }
a { text-decoration:none;color:inherit; }
button { cursor:pointer; }

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar { width:6px;height:6px; }
::-webkit-scrollbar-track { background:transparent; }
::-webkit-scrollbar-thumb { background:var(--gray-300);border-radius:99px; }
::-webkit-scrollbar-thumb:hover { background:var(--gray-400); }

/* ===== AUTH PAGES ===== */
.auth-wrapper {
    min-height:100vh;
    display:flex;
    align-items:center;
    justify-content:center;
    background:linear-gradient(135deg,#667eea 0%,#764ba2 100%);
    padding:20px;
}
.auth-card {
    background:#fff;
    border-radius:var(--radius-xl);
    box-shadow:var(--shadow-lg);
    padding:clamp(24px,5vw,40px);
    width:100%;
    max-width:420px;
    animation:authSlide 0.5s var(--ease);
}
@keyframes authSlide {
    from { opacity:0;transform:translateY(20px); }
    to { opacity:1;transform:translateY(0); }
}
.auth-card h2 { color:var(--primary);font-weight:800;font-size:clamp(1.4rem,4vw,1.7rem); }
.auth-card .form-control { border-radius:var(--radius);padding:12px 16px;border:1.5px solid var(--gray-200);font-size:15px;transition:var(--transition); }
.auth-card .form-control:focus { border-color:var(--primary);box-shadow:var(--shadow-glow); }
.auth-card .input-group-text { border-radius:var(--radius) 0 0 var(--radius);border:1.5px solid var(--gray-200);border-right:0;background:var(--gray-50);color:var(--gray-500); }
.auth-card .btn-primary { background:linear-gradient(135deg,var(--primary),var(--secondary));border:none;border-radius:var(--radius);padding:13px;font-weight:600;font-size:15px;transition:var(--transition); }
.auth-card .btn-primary:hover { transform:translateY(-1px);box-shadow:var(--shadow-glow);filter:brightness(1.05); }

/* ===== LAYOUT ===== */
.app-container { display:flex;min-height:100vh; }

/* ===== SIDEBAR ===== */
.sidebar {
    width:var(--sidebar-w);
    background:#fff;
    border-right:1px solid var(--border);
    position:fixed;
    top:0;left:0;
    height:100vh;
    z-index:1000;
    display:flex;
    flex-direction:column;
    transition:transform 0.3s var(--ease);
    overflow-y:auto;
}
.sidebar-header {
    padding:20px;
    text-align:center;
    border-bottom:1px solid var(--border);
    flex-shrink:0;
}
.sidebar-header h3 { color:var(--primary);font-weight:800;font-size:1.2rem;margin:0; }
.sidebar-nav { padding:12px 0;flex:1; }
.sidebar-nav .nav-link {
    display:flex;align-items:center;
    padding:11px 22px;
    color:var(--gray-600);
    font-weight:500;font-size:14px;
    border-left:3px solid transparent;
    transition:var(--transition);
    gap:10px;
}
.sidebar-nav .nav-link i { font-size:1.1rem;color:var(--gray-400);transition:var(--transition);width:20px;text-align:center; }
.sidebar-nav .nav-link:hover,
.sidebar-nav .nav-link.active {
    background:var(--primary-light);
    color:var(--primary);
    border-left-color:var(--primary);
}
.sidebar-nav .nav-link:hover i,
.sidebar-nav .nav-link.active i { color:var(--primary); }

/* ===== SIDEBAR OVERLAY ===== */
.sidebar-overlay {
    display:none;
    position:fixed;top:0;left:0;
    width:100%;height:100%;
    background:rgba(15,23,42,0.5);
    backdrop-filter:blur(4px);
    -webkit-backdrop-filter:blur(4px);
    z-index:999;
    opacity:0;
    transition:opacity 0.3s var(--ease);
}
.sidebar-overlay.show { display:block;opacity:1; }

/* ===== TOGGLE SIDEBAR ===== */
.toggle-sidebar {
    display:none;
    background:var(--card-bg);
    border:1px solid var(--border);
    border-radius:var(--radius);
    font-size:20px;
    color:var(--dark);
    padding:8px 12px;
    margin-bottom:16px;
    transition:var(--transition);
    box-shadow:var(--shadow-sm);
}
.toggle-sidebar:hover { background:var(--primary-light);color:var(--primary); }

/* ===== MAIN CONTENT ===== */
.main-content {
    flex:1;
    margin-left:var(--sidebar-w);
    padding:clamp(16px,3vw,30px);
    transition:var(--transition);
    min-height:100vh;
    overflow-x: hidden;
}

/* ===== STAT CARDS ===== */
.stat-card {
    background:#fff;
    border:1px solid var(--border);
    border-radius:var(--radius-lg);
    padding:clamp(14px,2vw,20px);
    display:flex;
    align-items:center;
    box-shadow:var(--shadow-sm);
    transition:var(--transition);
    gap:clamp(8px,2vw,16px);
}
.stat-card:hover { transform:translateY(-4px);box-shadow:var(--shadow-lg);border-color:transparent; }

.stat-icon {
    width:clamp(40px,8vw,56px);
    height:clamp(40px,8vw,56px);
    border-radius:var(--radius);
    display:flex;align-items:center;justify-content:center;
    font-size:clamp(16px,3vw,22px);
    flex-shrink:0;
}
.stat-icon.primary { background:var(--primary-light);color:var(--primary); }
.stat-icon.success { background:var(--success-light);color:var(--success); }
.stat-icon.warning { background:var(--warning-light);color:var(--warning); }
.stat-icon.danger { background:var(--danger-light);color:var(--danger); }

.stat-details h4 { margin:0;font-size:clamp(18px,3vw,26px);font-weight:700;line-height:1.2; }
.stat-details p { margin:0;color:var(--text-muted);font-size:clamp(11px,1.5vw,13px);font-weight:500; }

/* ===== CUSTOM CARD ===== */
.custom-card {
    background:#fff;
    border:1px solid var(--border);
    border-radius:var(--radius-xl);
    box-shadow:var(--shadow-sm);
    margin-bottom:24px;
    overflow:hidden;
}
.custom-card .card-header {
    background:transparent;
    border-bottom:1px solid var(--border);
    padding:18px 24px;
    font-weight:600;font-size:1rem;
    display:flex;justify-content:space-between;align-items:center;
}
.custom-card .card-body { padding:clamp(16px,3vw,24px); }

/* ===== NOTIFICATION BELL ===== */
.notification-wrapper { position:fixed;top:16px;right:20px;z-index:1050; }
.notification-wrapper .btn { width:42px;height:42px;padding:0;display:flex;align-items:center;justify-content:center;border-radius:var(--radius-full);border:1px solid var(--border);background:#fff;box-shadow:var(--shadow-sm);transition:var(--transition); }
.notification-wrapper .btn:hover { box-shadow:var(--shadow);border-color:var(--primary);color:var(--primary); }
.notification-wrapper .dropdown-menu { border:1px solid var(--border);border-radius:var(--radius-lg);box-shadow:var(--shadow-lg);overflow:hidden; }

/* ===== TABLES ===== */
.table { font-size:14px; }
.table thead th { font-weight:600;font-size:13px;text-transform:uppercase;letter-spacing:0.3px;color:var(--gray-500);border-bottom:2px solid var(--border);padding:12px; }
.table tbody td { padding:12px;vertical-align:middle;border-color:var(--gray-100); }
.table-hover tbody tr:hover { background:var(--primary-light); }

/* ===== AVATAR CIRCLE ===== */
.avatar-circle {
    width:40px;height:40px;
    border-radius:var(--radius-full);
    display:flex;align-items:center;justify-content:center;
    font-weight:600;font-size:14px;
    flex-shrink:0;
    background:linear-gradient(135deg,var(--primary-light),#ddd6fe);
    color:var(--primary);
}

/* ===== BUTTONS ===== */
.btn { border-radius:var(--radius);font-weight:500;font-size:14px;transition:var(--transition); }
.btn:active { transform:scale(0.97); }
.btn-primary { background:var(--primary);border-color:var(--primary); }
.btn-primary:hover { background:var(--primary-hover);border-color:var(--primary-hover);box-shadow:var(--shadow-glow); }
.btn-outline-primary { color:var(--primary);border-color:var(--primary); }
.btn-outline-primary:hover { background:var(--primary);border-color:var(--primary); }
.btn-success { background:var(--success); }
.btn-danger { background:var(--danger); }
.btn-warning { background:var(--warning); }

/* ===== GRADE BUTTONS ===== */
.grade-btn {
    width:clamp(30px,6vw,36px);height:clamp(30px,6vw,36px);
    border-radius:var(--radius-full)!important;
    display:inline-flex;align-items:center;justify-content:center;
    font-weight:700;font-size:clamp(10px,1.5vw,12px);
    padding:0;transition:var(--transition);
}
.grade-btn:hover { transform:scale(1.15);box-shadow:var(--shadow-glow); }
.grade-btn.btn-primary { background:linear-gradient(135deg,var(--primary),var(--secondary));border-color:transparent; }

/* ===== ATTENDANCE BUTTONS ===== */
.att-btn { transition:var(--transition);font-size:13px; }
.att-btn:hover { transform:scale(1.04); }
.btn-group .btn { border-radius:var(--radius-sm);margin:0 1px; }

/* ===== FORM CONTROLS ===== */
.form-control,.form-select {
    border-radius:var(--radius);
    border:1.5px solid var(--gray-200);
    padding:10px 14px;font-size:14px;
    transition:var(--transition);
}
.form-control:focus,.form-select:focus { border-color:var(--primary);box-shadow:var(--shadow-glow); }

/* ===== NAV TABS ===== */
.nav-tabs { border-bottom:2px solid var(--border);gap:4px; }
.nav-tabs .nav-link {
    border:none;border-radius:var(--radius) var(--radius) 0 0;
    font-weight:500;font-size:14px;
    color:var(--gray-500);
    padding:10px 18px;
    transition:var(--transition);
    position:relative;
}
.nav-tabs .nav-link:hover { color:var(--primary);background:var(--primary-light); }
.nav-tabs .nav-link.active {
    color:var(--primary);font-weight:600;background:transparent;
    border-bottom:none;
}
.nav-tabs .nav-link.active::after {
    content:'';position:absolute;bottom:-2px;left:0;right:0;
    height:3px;background:var(--primary);border-radius:3px 3px 0 0;
}

/* ===== BADGES ===== */
.badge { font-weight:500;border-radius:var(--radius-sm);padding:4px 10px;font-size:12px; }

/* ===== ALERTS ===== */
.alert { border-radius:var(--radius);border:none;font-size:14px; }

/* ===== CHAT ===== */
.chat-container {
    height:clamp(300px,50vh,450px);
    overflow-y:auto;
    padding:16px;
    background:var(--gray-50);
    border-radius:var(--radius-lg);
    border:1px solid var(--border);
}
.chat-message {
    margin-bottom:12px;
    display:flex;flex-direction:column;
    animation:chatIn 0.3s var(--ease);
}
@keyframes chatIn {
    from { opacity:0;transform:translateY(8px); }
    to { opacity:1;transform:translateY(0); }
}
.chat-message.me { align-items:flex-end; }
.chat-message.other { align-items:flex-start; }
.message-content {
    max-width:75%;
    padding:10px 16px;
    border-radius:var(--radius-lg);
    word-wrap:break-word;
    line-height:1.5;
    font-size:14px;
}
.chat-message.me .message-content {
    background:linear-gradient(135deg,var(--primary),var(--secondary));
    color:#fff;
    border-bottom-right-radius:4px;
}
.chat-message.other .message-content {
    background:#fff;
    color:var(--text);
    border-bottom-left-radius:4px;
    box-shadow:var(--shadow-sm);
    border:1px solid var(--gray-100);
}
.message-info { font-size:11px;color:var(--text-muted);margin-bottom:3px;font-weight:500; }
.message-views { 
    font-size: 10px; 
    color: var(--gray-400); 
    display: flex; 
    align-items: center; 
    gap: 4px; 
    cursor: help; 
    transition: var(--transition);
}
.chat-message.me .message-views { justify-content: flex-end; color: rgba(255,255,255,0.7); }
.chat-message.me .message-views:hover { color: #fff; }
.chat-message.other .message-views:hover { color: var(--primary); }

.chat-form .form-control { border-radius:var(--radius-full);padding:12px 20px; }
.chat-form .btn { border-radius:var(--radius-full);width:48px;height:48px;padding:0;display:flex;align-items:center;justify-content:center; }

/* ===== PROGRESS BAR ===== */
.progress { border-radius:var(--radius-full);height:22px;background:var(--gray-100); }
.progress-bar { border-radius:var(--radius-full);font-size:12px;font-weight:600; }

/* ===== TOAST ===== */
.toast { border-radius:var(--radius);box-shadow:var(--shadow-lg); }

/* ===== SPINNER ===== */
.spinner-border { width:2rem;height:2rem; }

/* ===== PRINT ===== */
@media print {
    .sidebar,.sidebar-overlay,.toggle-sidebar,.notification-wrapper,.btn,.chat-form,.nav-tabs { display:none!important; }
    .main-content { margin-left:0!important;padding:0!important; }
    .custom-card { box-shadow:none;border:1px solid #ddd; }
}

/* ===== RESPONSIVE — TABLET ===== */
@media (max-width:992px) {
    .main-content { padding:20px; }
    .stat-card { padding:14px; }
}

/* ===== RESPONSIVE — MOBILE ===== */
@media (max-width:768px) {
    .sidebar { transform:translateX(-100%);box-shadow:var(--shadow-lg); }
    .sidebar.show { transform:translateX(0); }
    .main-content { margin-left:0;padding:12px; }
    .toggle-sidebar { display:flex!important;align-items:center;gap:8px; }
    .notification-wrapper { top:12px;right:12px; }
    .notification-wrapper .btn { width:38px;height:38px; }
    .notification-wrapper .dropdown-menu { width:280px!important;right:0!important; }
    
    /* Cards */
    .stat-card { padding:12px;gap:10px;border-radius:var(--radius); }
    .stat-icon { width:38px;height:38px;font-size:15px;border-radius:var(--radius-sm); }
    .stat-details h4 { font-size:18px; }
    .stat-details p { font-size:11px; }
    .custom-card { border-radius:var(--radius-lg);margin-bottom:16px; }
    .custom-card .card-body { padding:14px; }
    
    /* Tables */
    .table { font-size:13px; }
    .table thead th { font-size:11px;padding:8px; }
    .table tbody td { padding:8px; }
    
    /* Chat */
    .chat-container { height:350px;padding:12px; }
    .message-content { max-width:85%;font-size:13px;padding:8px 14px; }
    .chat-form .form-control { padding:10px 16px;font-size:14px; }
    .chat-form .btn { width:42px;height:42px; }
    
    /* Tabs */
    .nav-tabs .nav-link { padding:8px 12px;font-size:13px; }
    
    /* Buttons */
    .btn-group-sm .btn { font-size:12px;padding:4px 8px; }
    .grade-btn { width:30px;height:30px;font-size:10px; }
    
    /* Grade buttons — horizontal scroll */
    .grade-buttons { flex-wrap:nowrap!important;overflow-x:auto;-webkit-overflow-scrolling:touch;scrollbar-width:none; }
    .grade-buttons::-webkit-scrollbar { display:none; }
    
    /* Auth */
    .auth-card { padding:24px;margin:10px; }
    
    /* Page header */
    .page-header h2 { font-size:1.1rem; }
    .action-buttons .btn { padding:6px 10px;font-size:12px; }
    
    /* Avatar */
    .avatar-circle { width:34px;height:34px;font-size:12px; }
}

/* ===== RESPONSIVE — SMALL MOBILE ===== */
@media (max-width:480px) {
    html { font-size:14px; }
    .main-content { padding:10px; }
    .stat-icon { width:34px;height:34px;font-size:14px; }
    .stat-details h4 { font-size:16px; }
    .custom-card .card-body { padding:12px; }
    .chat-container { height:300px; }
    .message-content { max-width:90%; }
    .btn-group .btn { padding:4px 6px;font-size:11px; }
    .grade-btn { width:28px;height:28px;font-size:9px; }
    .avatar-circle { width:30px;height:30px;font-size:11px; }
    .table thead th { font-size:10px;padding:6px; }
    .table tbody td { padding:6px; }
    .notification-wrapper .dropdown-menu { width:260px!important; }
}

/* ===== SAFE AREA (iPhone notch) ===== */
@supports (padding: env(safe-area-inset-bottom)) {
    .main-content { padding-bottom:calc(16px + env(safe-area-inset-bottom)); }
    .sidebar { padding-top:env(safe-area-inset-top); }
    .chat-form { padding-bottom:env(safe-area-inset-bottom); }
}

/* ===== TOUCH IMPROVEMENTS ===== */
@media (hover:none) and (pointer:coarse) {
    .btn,.att-btn,.grade-btn,.nav-link,.sidebar-nav .nav-link { min-height:44px; }
    .form-control,.form-select { min-height:44px;font-size:16px; }
    .grade-btn { min-height:36px;min-width:36px; }
    .att-btn { min-height:40px; }
}

/* ===== REDUCED MOTION ===== */
@media (prefers-reduced-motion:reduce) {
    *,*::before,*::after { animation-duration:0.01ms!important;transition-duration:0.01ms!important; }
}