:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --accent-color: #3b82f6;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
    --primary-color: #60a5fa;
    --secondary-color: #3b82f6;
    --accent-color: #93c5fd;
    --text-primary: #f9fafb;
    --text-secondary: #d1d5db;
    --bg-primary: #111827;
    --bg-secondary: #1f2937;
    --bg-tertiary: #374151;
    --border-color: #4b5563;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    background: var(--bg-secondary);
    color: var(--text-primary);
    transition: var(--transition);
    overflow-x: hidden;
}

/* Header Styles */
header {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(10px);
    transition: var(--transition);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.logo i {
    font-size: 2rem;
}

nav {
    display: flex;
    gap: 2rem;
    align-items: center;
}

nav a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    transition: var(--transition);
    position: relative;
}

nav a:hover {
    color: var(--primary-color);
    background: var(--bg-tertiary);
}

nav a.active {
    color: var(--primary-color);
    background: var(--bg-tertiary);
}

.theme-toggle {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 0.5rem;
    transition: var(--transition);
}

.theme-toggle:hover {
    color: var(--primary-color);
    background: var(--bg-tertiary);
}

/* Main Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 4rem 0;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-radius: 1rem;
    margin-bottom: 3rem;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="25" cy="25" r="1" fill="white" opacity="0.1"/><circle cx="75" cy="75" r="1" fill="white" opacity="0.1"/><circle cx="50" cy="10" r="0.5" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    opacity: 0.3;
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1rem;
    animation: fadeInUp 1s ease-out;
}

.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
    margin-bottom: 2rem;
    animation: fadeInUp 1s ease-out 0.2s both;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp 1s ease-out 0.4s both;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 0.5rem;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.btn-primary {
    background: white;
    color: var(--primary-color);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-secondary:hover {
    background: white;
    color: var(--primary-color);
    transform: translateY(-2px);
}

/* Section Styles */
section {
    background: var(--bg-primary);
    border-radius: 1rem;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

section:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    transform: scaleX(0);
    transition: var(--transition);
}

section:hover::before {
    transform: scaleX(1);
}

h2 {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

h2 i {
    color: var(--primary-color);
}

/* Profile Section */
.profile-intro {
    margin-bottom: 2rem;
}

.profile-card {
    background: linear-gradient(135deg, var(--bg-primary), var(--bg-secondary));
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: 2rem;
    display: flex;
    align-items: center;
    gap: 2rem;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.profile-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.profile-avatar {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    width: 120px;
    height: 120px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 2rem;
    flex-shrink: 0;
    box-shadow: var(--shadow-md);
    position: relative;
    overflow: hidden;
    border: 3px solid var(--bg-primary);
}

.profile-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center top;
    border-radius: 50%;
    transition: var(--transition);
}

.profile-avatar-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.8), rgba(59, 130, 246, 0.8));
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: var(--transition);
    border-radius: 50%;
}

.profile-avatar:hover .profile-avatar-overlay {
    opacity: 1;
}

.profile-avatar:hover .profile-image {
    transform: scale(1.1);
}

.profile-info h3 {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.profile-info .title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.profile-info .location {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

.profile-info .location i {
    color: var(--accent-color);
}

.profile-info .description {
    color: var(--text-secondary);
    line-height: 1.6;
    font-size: 0.95rem;
    margin-bottom: 1rem;
}

.flags-display {
    display: flex;
    gap: 1rem;
    align-items: center;
    margin-top: 1rem;
}

.flag-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--bg-tertiary);
    border-radius: 2rem;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.flag-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
    border-color: var(--primary-color);
}

.flag-emoji {
    font-size: 1.2rem;
    filter: drop-shadow(0 2px 4px rgba(0,0,0,0.1));
}

  .flag-label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-primary);
  }

  /* Assignment Meta */
  .assignment-meta {
    margin-top: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
  }

  .upload-date {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 500;
  }

  .upload-date i {
    color: var(--accent-color);
    font-size: 0.9rem;
  }

/* Card Grid */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

/* Assignments section - display one per line */
#assignments .card-grid {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

#assignments .card {
    width: 100%;
    max-width: none;
}

.card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1.5rem;
    transition: var(--transition);
    cursor: pointer;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.card h3 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
}

.card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Links */
a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--secondary-color);
    text-decoration: underline;
}

ul {
    list-style: none;
    padding: 0;
}

li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition);
}

li:last-child {
    border-bottom: none;
}

li:hover {
    background: var(--bg-tertiary);
    padding-left: 0.5rem;
    border-radius: 0.25rem;
}

/* Calendar */
.calendar-wrapper {
    background: var(--bg-primary);
    border-radius: 1rem;
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

.calendar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.calendar-header h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.calendar-nav-btn {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 0.5rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2.5rem;
    height: 2.5rem;
}

.calendar-nav-btn:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.calendar-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 1px;
    background: var(--border-color);
    border-radius: 0.5rem;
    overflow: hidden;
    margin-bottom: 1.5rem;
}

.calendar-day-header {
    background: var(--bg-tertiary);
    padding: 0.75rem;
    text-align: center;
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.calendar-days {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 1px;
    background: var(--border-color);
}

.calendar-day {
    background: var(--bg-primary);
    min-height: 3rem;
    padding: 0.5rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}

.calendar-day:hover {
    background: var(--bg-secondary);
}

.calendar-day.other-month {
    color: var(--text-secondary);
    opacity: 0.5;
}

.calendar-day.today {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
}

.calendar-day.has-events {
    background: var(--accent-color);
    color: white;
}

.calendar-day.has-events.today {
    background: var(--secondary-color);
}

.day-number {
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 0.25rem;
}

.day-events {
    display: flex;
    flex-wrap: wrap;
    gap: 0.125rem;
    width: 100%;
    justify-content: center;
}

.event-dot {
    width: 0.25rem;
    height: 0.25rem;
    background: currentColor;
    border-radius: 50%;
    opacity: 0.8;
}

.calendar-events {
    background: var(--bg-secondary);
    border-radius: 0.75rem;
    padding: 1.5rem;
    border: 1px solid var(--border-color);
}

.calendar-events h4 {
    color: var(--text-primary);
    margin-bottom: 1rem;
    font-size: 1.1rem;
    font-weight: 600;
}

.events-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.event-item {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 1rem;
    transition: var(--transition);
    cursor: pointer;
}

.event-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
    border-color: var(--primary-color);
}

.event-title {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
    font-size: 0.95rem;
}

.event-time {
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-bottom: 0.25rem;
}

.event-location {
    color: var(--accent-color);
    font-size: 0.8rem;
    font-weight: 500;
}

.event-description {
    color: var(--text-secondary);
    font-size: 0.8rem;
    margin-top: 0.5rem;
    line-height: 1.4;
}

/* Responsive Calendar */
@media (max-width: 768px) {
    .calendar-wrapper {
        padding: 1rem;
    }
    
    .calendar-header h3 {
        font-size: 1.2rem;
    }
    
    .calendar-day {
        min-height: 2.5rem;
        padding: 0.25rem;
    }
    
    .day-number {
        font-size: 0.8rem;
    }
    
    .calendar-events {
        padding: 1rem;
    }
    
    .event-item {
        padding: 0.75rem;
    }
}

/* Progress Bar */
.progress-container {
    background: var(--bg-tertiary);
    border-radius: 0.5rem;
    height: 0.5rem;
    margin: 1rem 0;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    border-radius: 0.5rem;
    transition: width 1s ease-in-out;
    position: relative;
}

.progress-bar::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    animation: shimmer 2s infinite;
}

/* Animations */
@keyframes fadeInUp {
    from {
    opacity: 0;
    transform: translateY(30px);
    }
    to {
    opacity: 1;
    transform: translateY(0);
    }
}

@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

/* Responsive Design */
@media (max-width: 768px) {
    .header-container {
    flex-direction: column;
    gap: 1rem;
    }

    nav {
    flex-wrap: wrap;
    justify-content: center;
    }

    .hero h1 {
    font-size: 2rem;
    }

    .hero-buttons {
    flex-direction: column;
    align-items: center;
    }

    .container {
    padding: 1rem;
    }

    section {
    padding: 1.5rem;
    }

    .card-grid {
    grid-template-columns: 1fr;
    }

    .profile-card {
    flex-direction: column;
    text-align: center;
    gap: 1rem;
    }

    .profile-avatar {
    width: 100px;
    height: 100px;
    }

    .profile-info h3 {
    font-size: 1.5rem;
    }

    .flags-display {
    flex-direction: column;
    gap: 0.5rem;
    }

        .flag-item {
      width: 100%;
      justify-content: center;
    }

    .assignment-meta {
      flex-direction: column;
      gap: 0.5rem;
    }
  }

/* Loading Animation */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid var(--border-color);
    border-radius: 50%;
    border-top-color: var(--primary-color);
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Notification */
.notification {
    position: fixed;
    top: 2rem;
    right: 2rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 1rem;
    box-shadow: var(--shadow-lg);
    transform: translateX(100%);
    transition: var(--transition);
    z-index: 1001;
}

.notification.show {
    transform: translateX(0);
}

/* Scroll to top button */
.scroll-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 1000;
}

.scroll-top.visible {
    opacity: 1;
    visibility: visible;
}

.scroll-top:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}