/*
 * StudySphere - Core Styles & Design System
 * Features a premium glassmorphism theme, smooth animations, and fully responsive layout.
 */

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

:root {
    /* Premium Dark Theme Variables (Default) */
    --bg-primary: #05050a;
    --bg-secondary: #0a0b14;
    --bg-surface: rgba(18, 19, 31, 0.45);
    --bg-surface-opaque: #12131f;
    --border-color: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(255, 255, 255, 0.15);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #475569;
    
    --primary: #818cf8;
    --primary-rgb: 129, 140, 248;
    --primary-glow: rgba(129, 140, 248, 0.25);
    --primary-hover: #6366f1;
    
    --secondary: #2dd4bf;
    --secondary-rgb: 45, 212, 191;
    --secondary-glow: rgba(45, 212, 191, 0.25);
    
    --accent: #f43f5e;
    --accent-rgb: 244, 63, 94;
    
    --warning: #fbbf24;
    --warning-rgb: 251, 191, 36;
    
    --glass-blur: blur(24px);
    --shadow-main: 0 10px 40px -10px rgba(0, 0, 0, 0.8), inset 0 1px 0 0 rgba(255, 255, 255, 0.05);
    --transition-speed: 0.3s;
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Inter', sans-serif;
}

[data-theme="light"] {
    /* Premium Light Theme Variables */
    --bg-primary: #f1f5f9;
    --bg-secondary: #ffffff;
    --bg-surface: rgba(255, 255, 255, 0.8);
    --bg-surface-opaque: #ffffff;
    --border-color: rgba(15, 23, 42, 0.08);
    --border-hover: rgba(15, 23, 42, 0.15);
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    
    --primary: #4f46e5;
    --primary-rgb: 79, 70, 229;
    --primary-glow: rgba(79, 70, 229, 0.15);
    --primary-hover: #4338ca;
    
    --secondary: #0d9488;
    --secondary-rgb: 13, 148, 136;
    --secondary-glow: rgba(13, 148, 136, 0.15);
    
    --accent: #e11d48;
    --accent-rgb: 225, 29, 72;
    
    --warning: #d97706;
    --warning-rgb: 217, 119, 6;
    
    --glass-blur: blur(20px);
    --shadow-main: 0 10px 40px -10px rgba(0, 0, 0, 0.08), inset 0 1px 0 0 rgba(255, 255, 255, 0.5);
}

/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-body);
    overflow-x: hidden;
    line-height: 1.5;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 600;
    color: var(--text-primary);
}

a {
    color: var(--primary);
    text-decoration: none;
    transition: color var(--transition-speed);
}

a:hover {
    color: var(--primary-hover);
}

button {
    font-family: var(--font-body);
    cursor: pointer;
    border: none;
    outline: none;
    background: none;
}

ul {
    list-style: none;
}

/* Scrollbar Styles */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

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

/* Sidebar Navigation */
.sidebar {
    width: 260px;
    background-color: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    z-index: 100;
    transition: transform var(--transition-speed) ease, background-color var(--transition-speed);
}

.sidebar-logo {
    padding: 24px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-weight: 800;
    font-size: 1.25rem;
    font-family: var(--font-heading);
    box-shadow: 0 4px 15px rgba(var(--primary-rgb), 0.3);
}

.logo-text {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 800;
    letter-spacing: -0.5px;
    background: linear-gradient(to right, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.sidebar-nav {
    flex: 1;
    padding: 0 16px;
    display: flex;
    flex-direction: column;
    gap: 6px;
    overflow-y: auto;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    color: var(--text-secondary);
    font-weight: 500;
    border-radius: var(--radius-md);
    transition: all var(--transition-speed) ease;
}

.nav-item i {
    width: 20px;
    height: 20px;
}

.nav-item:hover {
    color: var(--text-primary);
    background-color: rgba(var(--primary-rgb), 0.06);
    transform: translateX(4px);
}

.nav-item.active {
    color: #ffffff;
    background: linear-gradient(135deg, var(--primary), rgba(var(--primary-rgb), 0.8));
    box-shadow: 0 4px 15px rgba(var(--primary-rgb), 0.25);
}

[data-theme="light"] .nav-item.active {
    color: #ffffff;
}

.sidebar-footer {
    padding: 20px 16px;
    border-top: 1px solid var(--border-color);
}

.user-mini-profile {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 8px;
    border-radius: var(--radius-md);
    transition: background var(--transition-speed);
    cursor: pointer;
}

.user-mini-profile:hover {
    background: rgba(var(--primary-rgb), 0.06);
}

.user-mini-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--border-color);
}

.user-mini-info {
    overflow: hidden;
    white-space: nowrap;
    text-overflow: ellipsis;
    max-width: 140px;
}

.user-mini-name {
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text-primary);
}

.user-mini-role {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

/* Main Content Area */
.main-content {
    flex: 1;
    margin-left: 260px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    position: relative;
    transition: margin-left var(--transition-speed) ease;
}

/* Header / Top Bar */
.top-bar {
    height: 80px;
    padding: 0 40px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: rgba(var(--bg-primary), 0.8);
    backdrop-filter: var(--glass-blur);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 90;
    transition: background-color var(--transition-speed);
}

.hamburger-btn {
    display: none;
    font-size: 1.5rem;
    color: var(--text-primary);
}

.search-bar-container {
    position: relative;
    width: 320px;
}

.search-input {
    width: 100%;
    padding: 10px 16px 10px 42px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 0.9rem;
    transition: all var(--transition-speed) ease;
}

.search-input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-glow);
    outline: none;
}

.search-icon {
    position: absolute;
    left: 14px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    width: 18px;
    height: 18px;
    pointer-events: none;
}

.top-bar-actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

.theme-toggle-btn, .notifications-btn {
    width: 44px;
    height: 44px;
    border-radius: var(--radius-md);
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    transition: all var(--transition-speed) ease;
}

.theme-toggle-btn:hover, .notifications-btn:hover {
    border-color: var(--text-muted);
    background-color: rgba(var(--primary-rgb), 0.05);
}

.notification-badge {
    position: absolute;
    top: -2px;
    right: -2px;
    background-color: var(--accent);
    color: white;
    font-size: 0.7rem;
    font-weight: 700;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--bg-secondary);
}

/* Page Content Base */
.page-container {
    padding: 40px;
    flex: 1;
    opacity: 1;
    transform: translateY(0);
    transition: opacity 0.2s ease, transform 0.2s ease;
}

.page-container.fade-out {
    opacity: 0;
    transform: translateY(10px);
}

.page-header {
    margin-bottom: 32px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
}

.page-title-area h1 {
    font-size: 2rem;
    font-weight: 800;
    letter-spacing: -0.5px;
}

.page-title-area p {
    color: var(--text-secondary);
    margin-top: 4px;
    font-size: 0.95rem;
}

/* Glassmorphism Cards */
.glass-card {
    background: var(--bg-surface);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow-main);
    transition: border-color var(--transition-speed), transform var(--transition-speed), box-shadow var(--transition-speed);
}

.glass-card:hover {
    border-color: var(--border-hover);
}

.glass-card.interactive:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px 0 rgba(0,0,0,0.15);
    border-color: rgba(var(--primary-rgb), 0.2);
}

/* Buttons */
.btn {
    padding: 10px 20px;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 0.9rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: all var(--transition-speed) ease;
    cursor: pointer;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-hover));
    color: white;
    box-shadow: 0 4px 15px rgba(var(--primary-rgb), 0.2);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(var(--primary-rgb), 0.3);
}

.btn-secondary {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--border-hover);
    background-color: rgba(var(--primary-rgb), 0.05);
}

.btn-danger {
    background-color: rgba(244, 63, 94, 0.15);
    color: var(--accent);
    border: 1px solid rgba(244, 63, 94, 0.25);
}

.btn-danger:hover {
    background-color: var(--accent);
    color: white;
}

.btn-sm {
    padding: 6px 12px;
    font-size: 0.8rem;
    border-radius: var(--radius-sm);
}

.btn-icon {
    padding: 8px;
    border-radius: var(--radius-sm);
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}

.btn-icon:hover {
    color: var(--text-primary);
    border-color: var(--border-hover);
    background-color: var(--bg-primary);
}

.btn-icon.active {
    color: var(--accent);
    background-color: rgba(244, 63, 94, 0.1);
    border-color: rgba(244, 63, 94, 0.2);
}

/* Badges & Pills */
.badge {
    padding: 4px 10px;
    border-radius: 50px;
    font-size: 0.75rem;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.badge-primary {
    background-color: rgba(var(--primary-rgb), 0.12);
    color: var(--primary);
}

.badge-secondary {
    background-color: rgba(var(--secondary-rgb), 0.12);
    color: var(--secondary);
}

.badge-accent {
    background-color: rgba(var(--accent-rgb), 0.12);
    color: var(--accent);
}

.badge-warning {
    background-color: rgba(var(--warning-rgb), 0.12);
    color: var(--warning);
}

/* Inputs & Form Fields */
.form-group {
    margin-bottom: 20px;
}

.form-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 550;
    margin-bottom: 8px;
    color: var(--text-secondary);
}

.form-control {
    width: 100%;
    padding: 12px 16px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 0.95rem;
    transition: all var(--transition-speed) ease;
}

.form-control:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-glow);
    outline: none;
}

textarea.form-control {
    resize: vertical;
    min-height: 100px;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

/* Custom Modals */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(4px);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.modal-overlay.active {
    opacity: 1;
    pointer-events: auto;
}

.modal-container {
    width: 90%;
    max-width: 600px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-main);
    overflow: hidden;
    transform: scale(0.9);
    transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.modal-overlay.active .modal-container {
    transform: scale(1);
}

.modal-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.modal-header h3 {
    font-size: 1.25rem;
    font-weight: 700;
}

.modal-close-btn {
    font-size: 1.5rem;
    color: var(--text-secondary);
    transition: color 0.2s;
}

.modal-close-btn:hover {
    color: var(--text-primary);
}

.modal-body {
    padding: 24px;
    max-height: 70vh;
    overflow-y: auto;
}

.modal-footer {
    padding: 16px 24px;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: flex-end;
    gap: 12px;
}

/* Toast Notifications Container */
.toast-container {
    position: fixed;
    bottom: 24px;
    right: 24px;
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: 12px;
    max-width: 380px;
    width: 100%;
}

.toast {
    background-color: var(--bg-surface-opaque);
    border-left: 4px solid var(--primary);
    box-shadow: var(--shadow-main);
    border-radius: var(--radius-md);
    padding: 16px 20px;
    display: flex;
    align-items: flex-start;
    gap: 12px;
    color: var(--text-primary);
    transform: translateX(120%);
    animation: slideIn 0.3s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
    transition: transform 0.3s, opacity 0.3s;
}

.toast.toast-success { border-left-color: var(--secondary); }
.toast.toast-warning { border-left-color: var(--warning); }
.toast.toast-error { border-left-color: var(--accent); }
.toast.toast-info { border-left-color: var(--primary); }

.toast-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

.toast.toast-success .toast-icon { color: var(--secondary); }
.toast.toast-warning .toast-icon { color: var(--warning); }
.toast.toast-error .toast-icon { color: var(--accent); }
.toast.toast-info .toast-icon { color: var(--primary); }

.toast-content {
    flex: 1;
}

.toast-title {
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 2px;
}

.toast-message {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.toast-close {
    font-size: 1.1rem;
    color: var(--text-muted);
    cursor: pointer;
    line-height: 1;
}

.toast-close:hover {
    color: var(--text-primary);
}

@keyframes slideIn {
    to {
        transform: translateX(0);
    }
}

/* Responsive Styles */
@media (max-width: 1024px) {
    .main-content {
        margin-left: 0;
    }
    
    .sidebar {
        transform: translateX(-100%);
    }
    
    .sidebar.active {
        transform: translateX(0);
        box-shadow: 10px 0 30px rgba(0,0,0,0.5);
    }
    
    .hamburger-btn {
        display: block;
    }
    
    .top-bar {
        padding: 0 24px;
    }
    
    .page-container {
        padding: 24px;
    }
}

@media (max-width: 768px) {
    .top-bar {
        height: 70px;
    }
    
    .search-bar-container {
        display: none; /* Hide top search bar, handle inside pages if needed */
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .page-title-area h1 {
        font-size: 1.75rem;
    }
    
    .modal-container {
        width: 95%;
    }
}
/* ==========================================================================
   Site Footer — Feature #4
   ========================================================================== */

.site-footer {
  background: var(--bg-secondary, #1a1a2e);
  border-top: 1px solid var(--border-color, #2a2a3e);
  padding: 2rem 1.5rem;
  margin-top: auto;
  width: 100%;
}

.footer-content {
  max-width: 900px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  text-align: center;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.footer-logo {
  width: 32px;
  height: 32px;
  background: var(--accent-color, #6c63ff);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  color: #fff;
  font-size: 1rem;
}

.footer-name {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary, #ffffff);
}

.footer-tagline {
  color: var(--text-secondary, #a0a0b0);
  font-size: 0.85rem;
  margin: 0;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
}

.footer-links a {
  color: var(--text-secondary, #a0a0b0);
  text-decoration: none;
  font-size: 0.85rem;
  transition: color 0.2s ease;
}

.footer-links a:hover {
  color: var(--accent-color, #6c63ff);
}

.footer-copy {
  color: var(--text-secondary, #a0a0b0);
  font-size: 0.75rem;
  margin: 0;
}

/* Footer responsive */
@media (max-width: 480px) {
  .footer-links {
    gap: 0.75rem;
  }

  .footer-links a {
    font-size: 0.8rem;
  }
}