:root {
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --primary-light: #eef2ff;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --bg-main: #f8fafc;
    --bg-card: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --radius: 16px;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background: radial-gradient(circle at top right, #f1f5f9, #f8fafc);
    color: var(--text-main);
    line-height: 1.5;
    min-height: 100vh;
}

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

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 2rem;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    margin-bottom: 2rem;
}

h1 {
    font-size: 1.75rem;
    font-weight: 800;
    background: linear-gradient(to right, var(--primary), #8b5cf6);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.btn {
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    border: none;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
}

.btn:active {
    transform: scale(0.95);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-hover));
    color: white;
    box-shadow: 0 4px 14px 0 rgba(99, 102, 241, 0.39);
}

.btn-primary:hover {
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.45);
    transform: translateY(-1px);
}

.btn-outline {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(8px);
    border: 1px solid #e2e8f0;
    color: var(--text-main);
}

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

/* Calendar Styling */
#calendar {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 2rem;
    border-radius: 24px;
    box-shadow: var(--shadow-lg);
    border: 1px solid rgba(255, 255, 255, 0.5);
}

.fc .fc-toolbar-title {
    font-weight: 700;
    color: var(--text-main);
}

.fc .fc-button {
    border-radius: 12px !important;
    text-transform: capitalize !important;
    font-weight: 600 !important;
}

.fc .fc-button-primary {
    background-color: var(--primary) !important;
    border: none !important;
}

.fc .fc-button-primary:hover {
    background-color: var(--primary-hover) !important;
}

.fc .fc-day-today {
    background: var(--primary-light) !important;
}

/* Modal Styling */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(15, 23, 42, 0.6);
    backdrop-filter: blur(12px);
    animation: fadeIn 0.3s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

.modal-content {
    background: white;
    margin: 5% auto;
    padding: 2.5rem;
    border-radius: 24px;
    width: 90%;
    max-width: 550px;
    box-shadow: var(--shadow-lg);
    transform: translateY(20px);
    animation: slideUp 0.3s ease-out forwards;
}

@keyframes slideUp {
    to {
        transform: translateY(0);
    }
}

.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-muted);
}

.form-control {
    width: 100%;
    padding: 0.8rem 1rem;
    border: 2px solid #f1f5f9;
    border-radius: 12px;
    font-size: 1rem;
    transition: all 0.2s;
    background: #f8fafc;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
    background: white;
    box-shadow: 0 0 0 4px var(--primary-light);
}

/* Auth Utility */
.auth-nav {
    display: flex;
    gap: 1rem;
    align-items: center;
}

#username-text {
    color: var(--primary);
    font-weight: 700;
}

@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }

    header {
        flex-direction: column;
        gap: 1.5rem;
    }

    #calendar {
        padding: 1rem;
        border-radius: 16px;
    }
}