:root {
    --primary-black: #0a0a0a;
    --secondary-black: #1a1a1a;
    --accent-red: #dc2626;
    --accent-red-light: #ef4444;
    --accent-red-dark: #b91c1c;
    --text-white: #f8fafc;
    --text-gray: #cbd5e1;
    --border-dark: #374151;
    --shadow-red: rgba(220, 38, 38, 0.2);
    --success-green: #10b981;
    --error-red: #ef4444;
    --warning-yellow: #f59e0b;
    --info-blue: #3b82f6;
}
* { 
    margin: 0; 
    padding: 0; 
    box-sizing: border-box; 
}
body {
    font-family: 'Inter', sans-serif;
    background-color: var(--primary-black);
    color: var(--text-white);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
}
.container {
    width: 100%;
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 1.5rem;
}
.trainer-topbar {
    background-color: var(--secondary-black);
    border-bottom: 2px solid var(--accent-red);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
}
.trainer-topbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}
.trainer-title {
    color: var(--text-white);
    font-weight: 700;
    font-size: 1.3rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}
.trainer-actions {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}
.btn-trainer {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.6rem 1.2rem;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    font-size: 0.95rem;
    background-color: transparent;
    color: var(--text-white);
    border: 2px solid var(--border-dark);
    text-decoration: none;
    min-width: 100px;
}
.btn-trainer:hover {
    border-color: var(--accent-red);
    color: var(--accent-red-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(220, 38, 38, 0.2);
}
.btn-trainer.primary {
    background: linear-gradient(135deg, var(--accent-red), var(--accent-red-dark));
    border-color: var(--accent-red);
    color: white;
    box-shadow: 0 4px 15px var(--shadow-red);
}
.btn-trainer.primary:hover {
    background: linear-gradient(135deg, var(--accent-red-dark), #991b1b);
    border-color: var(--accent-red-dark);
    transform: translateY(-3px);
    box-shadow: 0 8px 25px var(--shadow-red);
}
.btn-trainer.active {
    border-color: var(--accent-red);
    background-color: rgba(220, 38, 38, 0.1);
    color: var(--accent-red-light);
    box-shadow: 0 0 0 2px rgba(220, 38, 38, 0.15);
}
.btn-trainer:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
    box-shadow: none !important;
}
.trainer-layout {
    padding: 2rem 0;
}
.trainer-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-top: 1.5rem;
}
.trainer-panel {
    background-color: var(--secondary-black);
    border: 1px solid var(--border-dark);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 10px 35px rgba(0, 0, 0, 0.4);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.trainer-panel:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.5);
}
.trainer-panel h2,
.trainer-panel h3 {
    color: var(--text-white);
    margin-bottom: 1rem;
    font-weight: 700;
}
.trainer-panel h2 {
    font-size: 1.5rem;
    border-bottom: 2px solid var(--accent-red);
    padding-bottom: 0.5rem;
}
.trainer-panel h3 {
    font-size: 1.25rem;
}
.trainer-panel p,
.trainer-panel li {
    color: var(--text-gray);
    margin-bottom: 0.75rem;
}
.trainer-panel ul,
.trainer-panel ol {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}
.trainer-panel code {
    background-color: rgba(220, 38, 38, 0.1);
    color: var(--accent-red-light);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
}
.trainer-panel pre {
    background-color: var(--primary-black);
    border: 1px solid var(--border-dark);
    border-radius: 10px;
    padding: 1.25rem;
    overflow: auto;
    margin: 1rem 0;
    position: relative;
}
.trainer-panel pre code {
    background: none;
    color: var(--text-white);
    padding: 0;
}
.trainer-panel blockquote {
    border-left: 4px solid var(--accent-red);
    padding-left: 1rem;
    margin: 1rem 0;
    color: var(--text-gray);
    font-style: italic;
}
.trainer-editor-container {
    display: flex;
    width: 100%;
    height: 340px;
    margin-top: 1rem;
    border-radius: 12px;
    border: 1px solid var(--border-dark);
    background-color: var(--primary-black);
    overflow: hidden;
    position: relative;
}
.trainer-line-numbers {
    width: 50px;
    min-width: 50px;
    padding: 1rem 0.5rem;
    text-align: right;
    font-family: 'Fira Code', 'Consolas', 'Monaco', monospace;
    font-size: 14px;
    line-height: 1.5;
    color: var(--text-gray);
    background-color: var(--secondary-black);
    border-right: 1px solid var(--border-dark);
    overflow-y: hidden;
    user-select: none;
    pointer-events: none;
}
.trainer-editor {
    flex: 1;
    height: 100%;
    padding: 1rem;
    border: none;
    background-color: var(--primary-black);
    color: var(--text-white);
    font-family: 'Fira Code', 'Consolas', 'Monaco', monospace;
    font-size: 15px;
    line-height: 1.5;
    outline: none;
    resize: none;
    overflow-y: auto;
    overflow-x: auto;
    white-space: pre;
    tab-size: 4;
    caret-color: var(--accent-red);
}
.trainer-editor::selection {
    background-color: rgba(220, 38, 38, 0.3);
}
.trainer-editor:focus {
    border-color: var(--accent-red);
    box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.15);
}
.trainer-output {
    margin-top: 1rem;
    background-color: var(--primary-black);
    border: 1px solid var(--border-dark);
    border-radius: 12px;
    padding: 1.25rem;
    min-height: 150px;
    max-height: 300px;
    overflow-y: auto;
    white-space: pre-wrap;
    color: var(--text-white);
    font-family: 'Fira Code', 'Consolas', 'Monaco', monospace;
    font-size: 14px;
    line-height: 1.6;
}
.trainer-output.error {
    border-color: var(--error-red);
    background-color: rgba(239, 68, 68, 0.05);
}
.trainer-output.success {
    border-color: var(--success-green);
    background-color: rgba(16, 185, 129, 0.05);
}
.lessons-navigation {
    margin-bottom: 1.5rem;
    padding: 1.25rem;
    background-color: var(--secondary-black);
    border-radius: 12px;
    border: 1px solid var(--border-dark);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.3);
}
.lessons-navigation h3 {
    color: var(--text-white);
    margin-bottom: 1rem;
    font-size: 1.2rem;
    font-weight: 600;
}
.lessons-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}
.lesson-link {
    display: inline-block;
    padding: 0.6rem 1rem;
    background-color: var(--primary-black);
    border: 2px solid var(--border-dark);
    border-radius: 8px;
    text-decoration: none;
    color: var(--text-gray);
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.3s ease;
    min-width: 60px;
    text-align: center;
}
.lesson-link:hover {
    border-color: var(--accent-red);
    color: var(--accent-red-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(220, 38, 38, 0.2);
}
.lesson-link.active {
    background-color: rgba(220, 38, 38, 0.1);
    border-color: var(--accent-red);
    color: var(--accent-red-light);
    font-weight: 600;
    box-shadow: 0 0 0 2px rgba(220, 38, 38, 0.2);
}
.lesson-pagination {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 1.5rem 0;
    padding: 1rem 0;
    border-top: 1px solid var(--border-dark);
    border-bottom: 1px solid var(--border-dark);
}
.btn-pagination {
    padding: 0.7rem 1.5rem;
    background-color: var(--secondary-black);
    border: 2px solid var(--border-dark);
    border-radius: 8px;
    color: var(--text-white);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    min-width: 160px;
}
.btn-pagination:hover:not(:disabled) {
    border-color: var(--accent-red);
    color: var(--accent-red-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(220, 38, 38, 0.2);
}
.btn-pagination:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}
.progress-text {
    font-weight: 700;
    color: var(--text-white);
    font-size: 1.1rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 1rem 1.5rem;
    border-radius: 10px;
    z-index: 10000;
    font-weight: 600;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.4);
    animation: slideIn 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    max-width: 400px;
    backdrop-filter: blur(10px);
}
.notification.success {
    background: linear-gradient(135deg, var(--success-green), #059669);
    color: white;
    border: 1px solid rgba(16, 185, 129, 0.3);
}
.notification.error {
    background: linear-gradient(135deg, var(--error-red), #dc2626);
    color: white;
    border: 1px solid rgba(239, 68, 68, 0.3);
}
.notification.info {
    background: linear-gradient(135deg, var(--info-blue), #2563eb);
    color: white;
    border: 1px solid rgba(59, 130, 246, 0.3);
}
.notification.warning {
    background: linear-gradient(135deg, var(--warning-yellow), #d97706);
    color: white;
    border: 1px solid rgba(245, 158, 11, 0.3);
}
@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}
@keyframes slideOut {
    from {
        transform: translateX(0);
        opacity: 1;
    }
    to {
        transform: translateX(100%);
        opacity: 0;
    }
}
.error-message {
    padding: 1rem;
    background-color: rgba(239, 68, 68, 0.1);
    border: 1px solid var(--error-red);
    border-radius: 8px;
    color: var(--accent-red-light);
    margin: 1rem 0;
}
.success-message {
    padding: 1rem;
    background-color: rgba(16, 185, 129, 0.1);
    border: 1px solid var(--success-green);
    border-radius: 8px;
    color: var(--success-green);
    margin: 1rem 0;
}
.loading {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 3rem;
}
.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-dark);
    border-top-color: var(--accent-red);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}
@keyframes spin {
    to { transform: rotate(360deg); }
}
.hint {
    background-color: rgba(59, 130, 246, 0.1);
    border-left: 4px solid var(--info-blue);
    padding: 1rem;
    margin: 1rem 0;
    border-radius: 0 8px 8px 0;
}
.hint h4 {
    color: var(--info-blue);
    margin-bottom: 0.5rem;
}
@media (max-width: 1024px) {
    .trainer-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    .trainer-editor-container {
        height: 300px;
    }
}
@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
    }
    .trainer-topbar .container {
        flex-direction: column;
        align-items: stretch;
        gap: 1rem;
    }
    .trainer-actions {
        justify-content: center;
    }
    .btn-trainer {
        flex: 1;
        min-width: 0;
        padding: 0.5rem 0.8rem;
        font-size: 0.9rem;
    }
    .trainer-title {
        text-align: center;
        font-size: 1.1rem;
    }
    .lesson-pagination {
        flex-direction: column;
        gap: 1rem;
    }
    .btn-pagination {
        width: 100%;
        min-width: 0;
    }
    .progress-text {
        order: -1;
        margin-bottom: 0.5rem;
    }
    .lessons-list {
        justify-content: center;
    }
    .trainer-panel {
        padding: 1.25rem;
    }
    .trainer-editor {
        font-size: 14px;
        padding: 0.75rem;
    }
}
@media (max-width: 480px) {
    .btn-trainer {
        padding: 0.4rem 0.6rem;
        font-size: 0.85rem;
    }
    .trainer-panel h2 {
        font-size: 1.3rem;
    }
    .trainer-panel h3 {
        font-size: 1.1rem;
    }
    .notification {
        left: 10px;
        right: 10px;
        max-width: none;
    }
}
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}
::-webkit-scrollbar-track {
    background: var(--secondary-black);
    border-radius: 10px;
}
::-webkit-scrollbar-thumb {
    background: var(--border-dark);
    border-radius: 10px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--accent-red);
}
::selection {
    background-color: rgba(220, 38, 38, 0.3);
    color: var(--text-white);
}
:focus-visible {
    outline: 2px solid var(--accent-red);
    outline-offset: 2px;
}
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}
.trainer-panel {
    animation: fadeInUp 0.5s ease-out;
}
.code-example {
    position: relative;
    margin: 1.5rem 0;
}
.code-example .copy-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    background: var(--secondary-black);
    border: 1px solid var(--border-dark);
    color: var(--text-gray);
    padding: 0.4rem 0.8rem;
    border-radius: 6px;
    font-size: 0.8rem;
    cursor: pointer;
    transition: all 0.3s;
}
.code-example .copy-btn:hover {
    background: var(--accent-red);
    color: white;
    border-color: var(--accent-red);
}
.difficulty-badge {
    display: inline-block;
    padding: 0.3rem 0.7rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    margin-left: 0.5rem;
    vertical-align: middle;
}
.difficulty-badge.easy {
    background: rgba(16, 185, 129, 0.2);
    color: var(--success-green);
    border: 1px solid rgba(16, 185, 129, 0.3);
}
.difficulty-badge.medium {
    background: rgba(245, 158, 11, 0.2);
    color: var(--warning-yellow);
    border: 1px solid rgba(245, 158, 11, 0.3);
}
.difficulty-badge.hard {
    background: rgba(239, 68, 68, 0.2);
    color: var(--error-red);
    border: 1px solid rgba(239, 68, 68, 0.3);
}