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

:root {
    --primary-color: #667eea;
    --primary-dark: #5568d3;
    --secondary-color: #764ba2;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-light: #f9fafb;
    --bg-white: #ffffff;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --glass-bg: rgba(255, 255, 255, 0.1);
    --glass-border: rgba(255, 255, 255, 0.2);
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    :root {
        --text-primary: #f9fafb;
        --text-secondary: #d1d5db;
        --bg-light: #1f2937;
        --bg-white: #374151;
        --border-color: #4b5563;
    }
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-light);
}

/* Login Page */
.login-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 20px;
}

.login-container {
    width: 100%;
    max-width: 400px;
}

.login-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    padding: 40px 30px;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.login-card h1 {
    text-align: center;
    margin-bottom: 10px;
    color: var(--text-primary);
    font-size: 28px;
}

.login-card .subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 30px;
    font-size: 14px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-primary);
    font-weight: 500;
    font-size: 14px;
}

.form-group input {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 16px;
    transition: all 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

/* Buttons */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    text-decoration: none;
    display: inline-block;
    text-align: center;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    width: 100%;
}

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

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

.btn-secondary:hover {
    background: var(--text-primary);
}

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

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

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

.btn-small {
    padding: 8px 16px;
    font-size: 14px;
}

.btn-large {
    padding: 15px 30px;
    font-size: 18px;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.error-message {
    color: var(--danger-color);
    margin-top: 10px;
    font-size: 14px;
    text-align: center;
}

/* Admin Page */
.admin-page {
    min-height: 100vh;
    background: var(--bg-light);
}

.admin-nav {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 15px 20px;
    box-shadow: var(--shadow-md);
}

.nav-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

.nav-content h2 {
    font-size: 22px;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 15px;
}

.username {
    font-size: 14px;
}

.admin-container {
    display: flex;
    max-width: 1400px;
    margin: 0 auto;
    min-height: calc(100vh - 70px);
}

.admin-sidebar {
    width: 250px;
    background: white;
    padding: 20px;
    box-shadow: var(--shadow-sm);
    border-right: 1px solid var(--border-color);
}

.sidebar-btn {
    width: 100%;
    padding: 15px;
    margin-bottom: 10px;
    border: none;
    border-radius: 10px;
    background: var(--bg-light);
    color: var(--text-primary);
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
    text-align: left;
    display: flex;
    align-items: center;
    gap: 10px;
}

.sidebar-btn:hover {
    background: #f3f4f6;
}

.sidebar-btn.active {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
}

.admin-main {
    flex: 1;
    padding: 30px;
    overflow-x: hidden;
}

.view {
    display: none;
}

.view.active {
    display: block;
}

.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
    gap: 15px;
}

.page-header h1 {
    font-size: 28px;
    color: var(--text-primary);
}

/* Papers Grid */
.papers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.paper-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-radius: 15px;
    padding: 20px;
    box-shadow: var(--shadow-md);
    transition: all 0.3s;
    border: 2px solid transparent;
}

.paper-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.paper-card.draft {
    border-color: var(--warning-color);
}

.paper-card.published {
    border-color: var(--success-color);
}

.paper-card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 15px;
}

.paper-card-header h3 {
    font-size: 18px;
    color: var(--text-primary);
    flex: 1;
    margin-right: 10px;
}

.paper-status {
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}

.paper-status.published {
    background: #d1fae5;
    color: var(--success-color);
}

.paper-status.draft {
    background: #fef3c7;
    color: var(--warning-color);
}

.paper-card-body {
    margin-bottom: 15px;
}

.paper-card-body p {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.paper-card-actions {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-secondary);
    font-size: 18px;
}

.loading {
    text-align: center;
    padding: 40px;
    color: var(--text-secondary);
}

/* Upload Page */
.upload-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 40px;
    box-shadow: var(--shadow-md);
    max-width: 800px;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.upload-form {
    width: 100%;
}

.file-upload-area {
    border: 3px dashed var(--border-color);
    border-radius: 15px;
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    background: var(--bg-light);
    position: relative;
}

.file-upload-area input[type="file"] {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    cursor: pointer;
    z-index: 1;
}

.file-upload-area:hover,
.file-upload-area.dragover {
    border-color: var(--primary-color);
    background: rgba(102, 126, 234, 0.05);
}

.file-upload-area input[type="file"] {
    display: none;
}

.file-upload-preview {
    pointer-events: none;
}

.upload-icon {
    font-size: 48px;
    display: block;
    margin-bottom: 15px;
}

.file-upload-preview p {
    color: var(--text-secondary);
    margin: 5px 0;
}

.file-info {
    font-size: 12px;
    color: var(--text-secondary);
}

.file-preview {
    margin-top: 20px;
}

.file-preview-item {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 15px;
    background: var(--bg-light);
    border-radius: 10px;
    margin-top: 10px;
}

.file-icon {
    font-size: 32px;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
}

.checkbox-label input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.upload-status {
    margin-top: 20px;
    text-align: center;
}

.uploading {
    color: var(--primary-color);
    font-weight: 600;
}

.upload-success {
    color: var(--success-color);
    font-weight: 600;
}

.upload-error {
    color: var(--danger-color);
    font-weight: 600;
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .admin-container {
        flex-direction: column;
    }

    .admin-sidebar {
        width: 100%;
        padding: 15px;
        display: flex;
        gap: 10px;
        overflow-x: auto;
    }

    .sidebar-btn {
        white-space: nowrap;
        min-width: 150px;
        margin-bottom: 0;
    }

    .admin-main {
        padding: 20px 15px;
    }

    .page-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .page-header h1 {
        font-size: 24px;
    }

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

    .upload-card {
        padding: 25px 20px;
    }

    .file-upload-area {
        padding: 30px 15px;
    }

    .paper-card-actions {
        flex-direction: column;
    }

    .paper-card-actions .btn {
        width: 100%;
    }

    .login-card {
        padding: 30px 20px;
    }

    .login-card h1 {
        font-size: 24px;
    }

    .nav-content {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 480px) {
    .admin-sidebar {
        padding: 10px;
    }

    .sidebar-btn {
        padding: 12px;
        font-size: 14px;
        min-width: 120px;
    }

    .upload-card {
        padding: 20px 15px;
    }

    .page-header h1 {
        font-size: 20px;
    }
}

/* Security - Prevent easy copying */
body {
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

img {
    -webkit-user-drag: none;
    -khtml-user-drag: none;
    -moz-user-drag: none;
    -o-user-drag: none;
    user-drag: none;
    pointer-events: none;
}

/* Print styles - disable printing */
@media print {
    body {
        display: none;
    }
}