/* Global Styles */
:root {
    --primary-bg: #070c16;
    --secondary-bg: #0d1524;
    --sidebar-bg: rgba(9, 15, 27, 0.95);
    --card-bg: rgba(14, 22, 36, 0.95);
    --border-color: rgba(100, 116, 139, 0.25);
    --text-primary: #f8fbff;
    --text-secondary: #98a9c6;
    --accent-blue: #3b82f6;
    --accent-purple: #8b5cf6;
    --accent-green: #22d3a6;
    --accent-yellow: #facc15;
    --accent-red: #f87171;
    --hover-bg: rgba(59, 130, 246, 0.12);
    --input-bg: rgba(10, 16, 28, 0.9);
    --shadow-soft: 0 24px 60px rgba(8, 12, 22, 0.55);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: radial-gradient(circle at top left, rgba(37, 99, 235, 0.25), transparent 45%),
                radial-gradient(circle at bottom right, rgba(124, 58, 237, 0.2), transparent 40%),
                var(--primary-bg);
    color: var(--text-primary);
    line-height: 1.6;
}

/* Loading Screen */
.loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--primary-bg);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    transition: opacity 0.3s ease;
}

/* CRITICAL: When hidden, don't block clicks */
.loading-screen[style*="display: none"],
.loading-screen[style*="visibility: hidden"] {
    pointer-events: none !important;
    opacity: 0 !important;
}

.loader {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--accent-blue);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Login Screen */
.login-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, var(--primary-bg) 0%, var(--secondary-bg) 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    transition: opacity 0.3s ease;
}

/* CRITICAL: When hidden, don't block clicks */
.login-screen[style*="display: none"],
.login-screen[style*="visibility: hidden"] {
    pointer-events: none !important;
    opacity: 0 !important;
}

.login-container {
    text-align: center;
    padding: 3rem;
    background: var(--card-bg);
    border-radius: 20px;
    border: 1px solid var(--border-color);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
}

.login-container h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.login-container p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
    font-size: 1.1rem;
}

/* App Container */
.app-container {
    display: flex;
    height: 100vh;
    overflow: hidden;
}

/* Sidebar */
.sidebar {
    width: 260px;
    background: linear-gradient(180deg, rgba(11, 19, 34, 0.95) 0%, rgba(7, 11, 20, 0.95) 100%);
    border-right: 1px solid rgba(59, 130, 246, 0.12);
    box-shadow: inset -1px 0 0 rgba(59, 130, 246, 0.08);
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    backdrop-filter: blur(18px);
}

.sidebar::-webkit-scrollbar {
    width: 6px;
}

.sidebar::-webkit-scrollbar-track {
    background: transparent;
}

.sidebar::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

/* Logo */
.logo {
    padding: 1.75rem 1.5rem 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.85rem;
    border-bottom: 1px solid rgba(59, 130, 246, 0.08);
}

.logo-icon {
    width: 42px;
    height: 42px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.35), rgba(139, 92, 246, 0.35));
    color: var(--text-primary);
    box-shadow: inset 0 0 0 1px rgba(59, 130, 246, 0.45);
}

.logo-text {
    font-size: 1.3rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* User Profile */
.user-profile {
    padding-bottom: 1rem;
}

.user-info {
    padding: 1rem 1.5rem;
}

.user-badge {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.badge-label {
    font-size: 0.875rem;
    font-weight: 600;
}

.badge-level {
    background: var(--accent-purple);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 700;
}

.user-email {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.user-xp {
    display: flex;
    justify-content: space-between;
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.xp-bar {
    height: 6px;
    background: var(--border-color);
    border-radius: 3px;
    overflow: hidden;
}

.xp-progress {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple));
    border-radius: 3px;
    transition: width 0.3s ease;
}

/* Navigation */
.nav-menu {
    flex: 1;
    padding: 1rem 0;
}

.nav-section {
    margin-bottom: 2rem;
}

.nav-section-title {
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--text-secondary);
    padding: 0 1.5rem;
    margin-bottom: 0.5rem;
    letter-spacing: 0.05em;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 0.85rem;
    padding: 0.7rem 1.35rem;
    margin: 0.15rem 0;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all 0.2s;
    border-radius: 12px;
}

.nav-item:hover {
    background: rgba(59, 130, 246, 0.12);
    color: var(--text-primary);
}

.nav-item.active {
    background: rgba(59, 130, 246, 0.18);
    color: var(--text-primary);
    box-shadow: inset 0 0 0 1px rgba(59, 130, 246, 0.35);
}

.nav-item[data-disabled="true"] {
    opacity: 0.6;
    cursor: not-allowed;
}

.nav-item[data-disabled="true"]:hover {
    background: transparent;
    color: var(--text-secondary);
}

.nav-item[data-disabled="true"] .nav-icon {
    background: rgba(59, 130, 246, 0.12);
    color: var(--text-secondary);
}

.nav-icon {
    width: 36px;
    height: 36px;
    border-radius: 12px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: rgba(59, 130, 246, 0.08);
    color: var(--text-secondary);
    transition: all 0.2s;
}

.nav-icon svg {
    width: 18px;
    height: 18px;
}

.nav-item:hover .nav-icon,
.nav-item.active .nav-icon {
    background: rgba(59, 130, 246, 0.2);
    color: var(--accent-blue);
}

.nav-text {
    flex: 1;
    font-size: 0.92rem;
    font-weight: 500;
}

.nav-badge {
    background: rgba(59, 130, 246, 0.18);
    color: var(--accent-blue);
    padding: 0.15rem 0.55rem;
    border-radius: 999px;
    font-size: 0.75rem;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.nav-tag {
    padding: 0.15rem 0.55rem;
    border-radius: 999px;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.nav-tag.new {
    background: rgba(34, 211, 178, 0.15);
    color: var(--accent-green);
}

.nav-tag.beta {
    background: rgba(250, 204, 21, 0.15);
    color: var(--accent-yellow);
}

.nav-tag.soon {
    background: rgba(148, 163, 184, 0.12);
    color: var(--text-secondary);
}

/* Sidebar Footer */
.sidebar-footer {
    padding: 1rem 1.5rem;
    border-top: 1px solid var(--border-color);
}

.btn-logout {
    width: 100%;
    padding: 0.75rem;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    transition: all 0.2s;
}

.btn-logout:hover {
    background: var(--hover-bg);
    border-color: var(--accent-red);
    color: var(--accent-red);
}

/* Main Content */
.main-content {
    flex: 1;
    overflow-y: auto;
    background: var(--primary-bg);
    margin-left: 260px;
    min-height: 100vh;
    padding: 24px;
    transition: margin-left 0.3s ease;
}

.main-content::-webkit-scrollbar {
    width: 8px;
}

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

.main-content::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

.main-content::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Page Container */
.page-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem;
}

.page-header {
    margin-bottom: 2rem;
}

.page-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.page-subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* Buttons */
.btn-primary {
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    color: white;
    padding: 0.875rem 2rem;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(74, 158, 255, 0.3);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.btn-secondary {
    background: var(--card-bg);
    color: var(--text-primary);
    padding: 0.875rem 2rem;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-secondary:hover {
    background: var(--hover-bg);
    border-color: var(--accent-blue);
}

/* Responsive */
@media (max-width: 768px) {
    .main-content {
        margin-left: 0;
        width: 100%;
    }
}

/* ============================================
   LOADING OVERLAY & STATES
   ============================================ */

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    z-index: 10001;
    display: flex;
    justify-content: center;
    align-items: center;
    animation: fadeIn 0.2s ease-out;
}

.loading-spinner-container {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
    text-align: center;
    min-width: 200px;
    border: 1px solid var(--border-color);
}

.loading-text {
    margin-top: 1rem;
    color: var(--text-primary);
    font-size: 0.875rem;
    font-weight: 500;
}

/* Spinner animation */
.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-top-color: var(--accent-blue);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin: 0 auto;
}

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

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* Inline spinner for buttons */
.inline-spinner {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid currentColor;
    border-top-color: transparent;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
    margin-right: 0.5rem;
    vertical-align: middle;
}

/* Loading disabled state */
.loading-disabled {
    opacity: 0.6;
    cursor: not-allowed !important;
    pointer-events: none;
}

/* Element loading state */
.element-loading {
    position: relative;
    pointer-events: none;
    opacity: 0.7;
}

/* Input validation styles */
.input-field.error,
.input-field:invalid {
    border-color: #ef4444 !important;
    background-color: rgba(239, 68, 68, 0.1);
}

.input-field.success {
    border-color: #10b981 !important;
    background-color: rgba(16, 185, 129, 0.1);
}

.validation-message {
    font-size: 0.875rem;
    margin-top: 0.25rem;
    display: none;
}

.validation-message.error {
    color: #ef4444;
    display: block;
}

.validation-message.success {
    color: #10b981;
    display: block;
}

/* Show validation icon */
.input-wrapper {
    position: relative;
}

.input-wrapper::after {
    content: '';
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    width: 20px;
    height: 20px;
    display: none;
}

.input-wrapper.error::after {
    content: '✕';
    color: #ef4444;
    display: block;
    font-size: 18px;
    font-weight: bold;
}

.input-wrapper.success::after {
    content: '✓';
    color: #10b981;
    display: block;
    font-size: 18px;
    font-weight: bold;
}

/* ============================================
   OFFLINE DETECTION BANNER
   ============================================ */

.offline-banner {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: linear-gradient(135deg, #ef4444, #dc2626);
    color: white;
    padding: 0.75rem 1rem;
    display: none;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    font-size: 0.875rem;
    font-weight: 500;
    z-index: 10002;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
    animation: slideDown 0.3s ease-out;
}

@keyframes slideDown {
    from {
        transform: translateY(-100%);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

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

@media (max-width: 768px) {
    .offline-banner {
        font-size: 0.8125rem;
        padding: 0.625rem 0.875rem;
    }

    .offline-icon {
        width: 18px;
        height: 18px;
    }
}