:root {
    /* Paleta Corporativa / Profesional */
    --primary-color: #2563eb; /* Blue 600 */
    --secondary-color: #3b82f6; /* Blue 500 */
    
    --bg-color-light: #f8fafc; /* Slate 50 */
    --text-color-light: #0f172a; /* Slate 900 */
    --card-bg-light: #ffffff;
    --card-border-light: #e2e8f0; /* Slate 200 */
    
    --bg-color-dark: #0f172a; /* Slate 900 */
    --text-color-dark: #f8fafc; /* Slate 50 */
    --card-bg-dark: #1e293b; /* Slate 800 */
    --card-border-dark: #334155; /* Slate 700 */
}

body.dark-mode {
    --bg-color: var(--bg-color-dark);
    --text-color: var(--text-color-dark);
    --card-bg: var(--card-bg-dark);
    --card-border: var(--card-border-dark);
}

body:not(.dark-mode) {
    --bg-color: var(--bg-color-light);
    --text-color: var(--text-color-light);
    --card-bg: var(--card-bg-light);
    --card-border: var(--card-border-light);
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

.course-card {
    background-color: var(--card-bg);
    border-color: var(--card-border);
    position: relative;
    overflow: hidden;
}

.locked-card {
    background-color: rgba(148, 163, 184, 0.1); /* Slate 400 with opacity */
    color: #94a3b8; /* Slate 400 */
    border-color: var(--card-border);
    cursor: not-allowed;
}

.locked-card h3 {
    opacity: 0.5;
}

.unlocked-card {
    border-left: 4px solid #94a3b8; /* Slate 400 indicator */
}

.completed-card {
    border-color: #10b981; /* Emerald 500 */
    border-left: 4px solid #10b981;
    background-color: rgba(16, 185, 129, 0.05); /* Slight emerald tint */
}

.completed-card h3 {
    color: #059669; /* Emerald 600 */
}
.dark-mode .completed-card h3 {
    color: #34d399; /* Emerald 400 */
}

.lock-icon {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 2rem;
    color: rgba(148, 163, 184, 0.2);
    z-index: 10;
}

.checkmark {
    position: absolute;
    top: 15px;
    right: 15px;
    color: #10b981; /* Emerald 500 */
    font-size: 1.5rem;
    animation: popIn 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes popIn {
    0% { transform: scale(0); opacity: 0; }
    100% { transform: scale(1); opacity: 1; }
}

.cycle-header {
    position: sticky;
    top: 0;
    background-color: var(--bg-color);
    z-index: 10;
    transition: background-color 0.3s ease;
}

@media (max-width: 768px) {
    .cycle-container {
        overflow-x: auto;
        padding-bottom: 10px;
    }
    .cycle-courses {
        min-width: 800px; /* Ensure horizontal scroll on mobile if needed */
    }
}

/* Toast notification styling override */
.toastify {
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    border-radius: 8px;
    font-family: inherit;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

/* Focus styling for accessibility */
button:focus,
input:focus,
.course-card:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}