:root {
    --color-white: rgba(255, 255, 255, 1);
    --color-black: rgba(0, 0, 0, 1);
    --color-gray-200: rgba(245, 245, 245, 1);
    --color-gray-300: rgba(167, 169, 169, 1);
    --color-gray-400: rgba(119, 124, 124, 1);
    --color-slate-500: rgba(98, 108, 113, 1);
    --color-charcoal-700: rgba(31, 33, 33, 1);
    --color-charcoal-800: rgba(38, 40, 40, 1);
    --color-slate-900: rgba(19, 52, 59, 1);
    --color-teal-300: rgba(50, 184, 198, 1);
    --color-teal-500: rgba(33, 128, 141, 1);
    --color-teal-600: rgba(29, 116, 128, 1);
    --color-blue-400: rgba(64, 158, 255, 1);
    --color-blue-500: rgba(33, 120, 199, 1);
    --color-background: #232323;
    --color-surface: #252525;
    --color-surface-elevated: #2c2c2c;
    --color-text: var(--color-gray-200);
    --color-text-secondary: rgba(187, 187, 187, 0.9);
    --color-primary: var(--color-blue-400);
    --color-primary-hover: var(--color-blue-500);
    --color-border: rgba(57, 57, 57, 1);
    --color-card-border: rgba(57, 57, 57, 0.6);
    --font-family-base: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-size-base: 14px;
    --font-size-lg: 16px;
    --font-size-xl: 18px;
    --font-size-2xl: 20px;
    --font-size-3xl: 24px;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    --space-8: 8px;
    --space-12: 12px;
    --space-16: 16px;
    --space-20: 20px;
    --space-24: 24px;
    --space-32: 32px;
    --space-48: 48px;
    --radius-base: 8px;
    --radius-lg: 12px;
    --radius-xl: 18px;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3), 0 1px 2px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 8px 24px rgba(64, 158, 255, 0.2);
    --duration-fast: 150ms;
    --duration-normal: 200ms;
    --ease-standard: cubic-bezier(0.16, 1, 0.3, 1);
}

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

body {
    font-family: var(--font-family-base);
    font-size: var(--font-size-base);
    line-height: 1.5;
    color: var(--color-text);
    background-color: var(--color-charcoal-700);
    -webkit-font-smoothing: antialiased;
}

.course-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--space-32) var(--space-20);
}

/* Баннер авторизации */
.auth-banner {
    background: linear-gradient(135deg, #409eff 0%, #2178c7 100%);
    border-radius: var(--radius-xl);
    padding: var(--space-48) var(--space-32);
    margin-bottom: var(--space-48);
    text-align: center;
    box-shadow: 0 4px 24px rgba(64, 158, 255, 0.3);
}

.auth-banner-content {
    max-width: 600px;
    margin: 0 auto;
}

.auth-banner-title {
    color: var(--color-white);
    font-size: 2rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: 1rem;
}

.auth-banner-text {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.1rem;
    margin-bottom: 2rem;
}

.auth-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.auth-btn {
    display: inline-block;
    padding: 0.9rem 2rem;
    font-size: 1rem;
    font-weight: var(--font-weight-semibold);
    border-radius: 10px;
    text-decoration: none;
    transition: all var(--duration-normal) var(--ease-standard);
    cursor: pointer;
    border: 2px solid transparent;
}

.auth-btn-login {
    background-color: var(--color-white);
    color: #409eff;
    border-color: var(--color-white);
}

.auth-btn-login:hover {
    background-color: transparent;
    color: var(--color-white);
    border-color: var(--color-white);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(255, 255, 255, 0.3);
}

.auth-btn-register {
    background-color: transparent;
    color: var(--color-white);
    border-color: var(--color-white);
}

.auth-btn-register:hover {
    background-color: var(--color-white);
    color: #409eff;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(255, 255, 255, 0.3);
}

/* Заголовок курсов */
.courses-header {
    margin-bottom: var(--space-32);
    text-align: center;
}

.courses-title {
    color: var(--color-text);
    font-size: 2.5rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: 0.5rem;
}

.courses-subtitle {
    color: var(--color-text-secondary);
    font-size: var(--font-size-lg);
}

/* Сетка курсов */
.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--space-24);
    margin-top: var(--space-32);
}

/* Карточка курса */
.course-card {
    background-color: var(--color-surface);
    border: 1px solid var(--color-card-border);
    border-radius: var(--radius-xl);
    padding: var(--space-32);
    text-align: center;
    cursor: pointer;
    transition: all var(--duration-normal) var(--ease-standard);
    position: relative;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.course-icon {
    font-size: 4rem;
    margin-bottom: var(--space-20);
    display: block;
}

.course-name {
    color: var(--color-text);
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--space-12);
}

.course-description {
    color: var(--color-text-secondary);
    font-size: var(--font-size-base);
    margin-bottom: var(--space-24);
    line-height: 1.6;
}

/* Кнопки курсов */
.course-btn {
    display: inline-block;
    width: 100%;
    padding: 0.9rem 1.5rem;
    background-color: var(--color-primary);
    color: var(--color-white);
    font-weight: var(--font-weight-semibold);
    font-size: var(--font-size-base);
    border: none;
    border-radius: 10px;
    text-decoration: none;
    cursor: pointer;
    transition: all var(--duration-normal) var(--ease-standard);
}

.course-btn:hover {
    background-color: var(--color-primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(64, 158, 255, 0.3);
}

.course-btn-disabled {
    background-color: #555;
    color: #999;
    cursor: not-allowed;
    opacity: 0.6;
}

.course-btn-disabled:hover {
    background-color: #555;
    transform: none;
    box-shadow: none;
}

.course-progress {
    display: flex;
    align-items: center;
    gap: 10px;
    margin: 12px 0;
}
.progress-bar {
    flex: 1;
    height: 6px;
    background: rgba(255,255,255,0.1);
    border-radius: 3px;
    overflow: hidden;
}
.progress-fill {
    height: 100%;
    background: #32B8C6;
    border-radius: 3px;
    transition: width 0.4s ease;
}
.progress-label {
    font-size: 12px;
    color: #aaa;
    white-space: nowrap;
}

.course-locked {
    opacity: 0.5;
    position: relative;
    filter: grayscale(50%);
}

.lock-badge {
    position: absolute;
    top: 12px;
    right: 12px;
    font-size: 20px;
}

.locked-text {
    font-size: 12px;
    color: #888;
    text-align: center;
    margin: 8px 0;
}

.course-btn-locked {
    background: #555 !important;
    cursor: not-allowed !important;
    opacity: 0.7;
}

/* Адаптивность */
@media (max-width: 1200px) {
    .courses-grid {
        grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    }
}

@media (max-width: 768px) {
    .course-container {
        padding: var(--space-24) var(--space-16);
    }

    .auth-banner {
        padding: var(--space-32) var(--space-24);
        margin-bottom: var(--space-32);
    }

    .auth-banner-title {
        font-size: 1.5rem;
    }

    .auth-banner-text {
        font-size: 1rem;
    }

    .auth-buttons {
        flex-direction: column;
    }

    .auth-btn {
        width: 100%;
    }

    .courses-title {
        font-size: 2rem;
    }

    .courses-grid {
        grid-template-columns: 1fr;
        gap: var(--space-16);
    }

    .course-card {
        padding: var(--space-24);
    }
}

@media (max-width: 480px) {
    .auth-banner-title {
        font-size: 1.3rem;
    }

    .courses-title {
        font-size: 1.5rem;
    }

    .course-icon {
        font-size: 3rem;
    }
}