/* ===========================
   BUTTONS
   =========================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.7rem 1.5rem;
    font-size: 0.95rem;
    font-weight: 500;
    font-family: var(--font-sans);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
    cursor: pointer;
    border: none;
    position: relative;
    letter-spacing: 0.01em;
}

.btn svg {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
}

.btn-primary {
    background-color: var(--color-primary);
    color: white;
    box-shadow: 0 2px 8px rgba(45, 90, 142, 0.25);
}

.btn-primary:hover {
    background-color: var(--color-primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(45, 90, 142, 0.3);
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: 0 1px 4px rgba(45, 90, 142, 0.2);
}

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

.btn-secondary:hover {
    background-color: var(--color-secondary-hover);
    transform: translateY(-1px);
}

.btn-outline {
    background-color: transparent;
    color: var(--color-text-primary);
    border: 1px solid var(--color-border);
}

.btn-outline:hover {
    background-color: var(--color-surface-alt);
    border-color: var(--color-text-muted);
}

.btn-block {
    display: flex;
    width: 100%;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
    border-radius: var(--radius-sm);
}


/* ===========================
   NAVBAR
   =========================== */
.navbar {
    padding: var(--space-3) 0;
    position: sticky;
    top: 0;
    background-color: rgba(248, 246, 241, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    z-index: 200;
    border-bottom: 1px solid transparent;
    transition: border-color var(--transition-base), box-shadow var(--transition-base);
}

.navbar.scrolled {
    border-bottom-color: var(--color-border-light);
    box-shadow: 0 1px 8px rgba(0,0,0,0.04);
}

.navbar-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.3rem;
    letter-spacing: -0.03em;
    cursor: pointer;
    transition: opacity var(--transition-fast);
}

.logo:hover {
    opacity: 0.7;
}

.logo-bold {
    font-weight: 700;
    color: var(--color-text-primary);
}

.logo-light {
    font-weight: 400;
    color: var(--color-primary);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

/* Theme Toggle Button */
.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 1px solid var(--color-border-light);
    background: var(--color-surface);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-base);
    color: var(--color-text-secondary);
    flex-shrink: 0;
}

.theme-toggle:hover {
    background: var(--color-secondary);
    color: var(--color-text-primary);
    transform: rotate(15deg);
    border-color: var(--color-text-muted);
}

.theme-toggle svg {
    width: 18px;
    height: 18px;
    transition: transform var(--transition-base);
}

/* Show sun by default (light mode), hide moon */
.theme-icon-moon {
    display: none;
}

.theme-icon-sun {
    display: block;
}

/* In dark mode: show moon, hide sun */
[data-theme="dark"] .theme-icon-sun {
    display: none;
}

[data-theme="dark"] .theme-icon-moon {
    display: block;
}

/* Keyboard shortcut hint for navbar */
.nav-kbd {
    display: none;
    font-size: 0.7rem;
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    background: var(--color-secondary);
    color: var(--color-text-muted);
    font-family: var(--font-sans);
    border: 1px solid var(--color-border-light);
}

@media (min-width: 1024px) {
    .nav-kbd {
        display: inline;
    }
}


/* ===========================
   BREADCRUMBS
   =========================== */
.breadcrumbs {
    display: flex;
    align-items: center;
    gap: var(--space-1);
    font-size: 0.82rem;
    color: var(--color-text-muted);
    flex-wrap: wrap;
}

.crumb {
    padding: 0.2rem 0.6rem;
    border-radius: var(--radius-sm);
    background-color: transparent;
    transition: all var(--transition-fast);
}

a.crumb:hover {
    background-color: var(--color-secondary);
    color: var(--color-text-primary);
}

.crumb.active {
    background-color: var(--color-primary-light);
    color: var(--color-primary);
    font-weight: 500;
}

.crumb-sep {
    color: var(--color-border);
    font-size: 0.75rem;
    user-select: none;
}


/* ===========================
   EDITORIAL CONTENT (SLIDES)
   =========================== */
.slide-content {
    font-family: var(--font-sans);
    color: var(--color-text-primary);
    line-height: 1.8;
}

.slide-content h3 {
    font-family: var(--font-serif);
    font-size: 2rem;
    margin-bottom: var(--space-4);
    color: var(--color-text-primary);
    border-bottom: 2px solid var(--color-border-light);
    padding-bottom: var(--space-2);
}

.slide-content h4 {
    font-size: 1.2rem;
    font-family: var(--font-sans);
    font-weight: 600;
    margin-top: var(--space-5);
    margin-bottom: var(--space-3);
    color: var(--color-primary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.slide-content p {
    font-size: 1.1rem;
    margin-bottom: var(--space-4);
    color: var(--color-text-secondary);
}

.editorial-quote {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    font-style: italic;
    color: var(--color-text-primary);
    border-left: 4px solid var(--color-accent);
    padding: var(--space-4) var(--space-5);
    margin: var(--space-5) 0;
    line-height: 1.5;
    background: linear-gradient(135deg, var(--color-accent-light) 0%, rgba(255,255,255,0) 100%);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.editorial-list {
    margin-bottom: var(--space-5);
    padding-left: 0;
    list-style: none;
}

.editorial-list li {
    position: relative;
    padding-left: var(--space-5);
    margin-bottom: var(--space-3);
    font-size: 1.1rem;
    color: var(--color-text-secondary);
}

.editorial-list li::before {
    content: '';
    position: absolute;
    left: 6px;
    top: 10px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background-color: var(--color-accent);
}

.editorial-list li strong {
    color: var(--color-text-primary);
}

.editorial-table-wrapper {
    overflow-x: auto;
    margin: var(--space-6) 0;
    background: var(--color-surface);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border-light);
}

.editorial-table {
    width: 100%;
    border-collapse: collapse;
    min-width: 600px;
}

.editorial-table th {
    background-color: var(--color-surface-alt);
    color: var(--color-text-primary);
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.8rem;
    letter-spacing: 0.06em;
    padding: var(--space-3) var(--space-4);
    text-align: left;
}

.editorial-table td {
    padding: var(--space-3) var(--space-4);
    border-top: 1px solid var(--color-border-light);
    font-size: 1rem;
    color: var(--color-text-secondary);
    vertical-align: top;
}

.editorial-highlight {
    background: linear-gradient(135deg, #FDF4E5 0%, #FFF9F0 100%);
    padding: var(--space-4);
    border-radius: var(--radius-md);
    margin: var(--space-5) 0;
    color: #8C6A2F;
    border-left: 4px solid var(--color-accent);
}

.editorial-highlight p {
    color: currentColor;
    margin-bottom: 0;
}


/* ===========================
   FLASHCARDS
   =========================== */
.flashcards-container {
    max-width: 680px;
    margin: 0 auto;
}

.fc-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-3);
}

.fc-counter {
    font-size: 1rem;
    color: var(--color-text-muted);
    font-weight: 500;
}

.fc-counter-current {
    font-size: 1.3rem;
    color: var(--color-text-primary);
    font-weight: 700;
}

.fc-dots {
    display: flex;
    justify-content: center;
    gap: 5px;
    margin-bottom: var(--space-5);
    flex-wrap: wrap;
}

.fc-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--color-border);
    transition: all var(--transition-base);
}

.fc-dot.done {
    background: var(--color-primary);
    opacity: 0.4;
}

.fc-dot.active {
    background: var(--color-primary);
    transform: scale(1.4);
    opacity: 1;
}

/* Card wrapper for perspective */
.fc-card-wrapper {
    perspective: 1200px;
    margin-bottom: var(--space-5);
    cursor: pointer;
}

.fc-card {
    position: relative;
    width: 100%;
    min-height: 320px;
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    transform-style: preserve-3d;
}

.fc-card.flipped {
    transform: rotateY(180deg);
}

.fc-card-face {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: var(--space-6) var(--space-5);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.fc-card-front {
    background: linear-gradient(145deg, var(--color-surface) 0%, var(--color-surface-alt) 100%);
    border: 2px solid var(--color-border-light);
}

.fc-card-back {
    background: linear-gradient(145deg, var(--color-primary) 0%, var(--color-primary-hover) 100%);
    border: 2px solid var(--color-primary);
    transform: rotateY(180deg);
    color: white;
}

.fc-card-label {
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    margin-bottom: var(--space-4);
    opacity: 0.5;
}

.fc-card-front .fc-card-label {
    color: var(--color-accent);
    opacity: 1;
}

.fc-card-back .fc-card-label {
    color: rgba(255, 255, 255, 0.7);
}

.fc-card-text {
    font-family: var(--font-serif);
    font-size: 1.4rem;
    line-height: 1.6;
    max-width: 540px;
    margin: 0;
}

.fc-card-front .fc-card-text {
    color: var(--color-text-primary);
}

.fc-card-back .fc-card-text {
    color: white;
    font-family: var(--font-sans);
    font-size: 1.15rem;
}

.fc-card-hint {
    position: absolute;
    bottom: var(--space-3);
    font-size: 0.75rem;
    opacity: 0.4;
    font-weight: 500;
}

.fc-card-front .fc-card-hint {
    color: var(--color-text-muted);
}

.fc-card-back .fc-card-hint {
    color: rgba(255, 255, 255, 0.6);
}

/* Navigation */
.fc-nav {
    display: flex;
    justify-content: center;
    gap: var(--space-3);
    margin-bottom: var(--space-4);
}

.fc-nav-btn {
    min-width: 140px;
}

.fc-nav-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
    transform: none !important;
}

/* Keyboard hint */
.fc-keyboard-hint {
    text-align: center;
    font-size: 0.8rem;
    color: var(--color-text-muted);
    margin-bottom: var(--space-2);
}

.fc-keyboard-hint kbd {
    display: inline-block;
    padding: 0.15rem 0.5rem;
    font-size: 0.75rem;
    font-family: var(--font-sans);
    background: var(--color-secondary);
    border: 1px solid var(--color-border-light);
    border-radius: 4px;
    margin: 0 0.1rem;
}

/* Flashcard button in subject view */
.subject-unit-footer-flashcards {
    border-top: none !important;
    padding-top: 0 !important;
    color: var(--color-accent) !important;
}

.subject-unit-footer-flashcards span {
    color: var(--color-accent);
}

.subject-unit-footer-flashcards svg {
    color: var(--color-accent);
}

/* Mobile responsive */
@media (max-width: 640px) {
    .fc-card {
        min-height: 280px;
    }
    
    .fc-card-face {
        padding: var(--space-5) var(--space-4);
    }
    
    .fc-card-text {
        font-size: 1.15rem;
    }
    
    .fc-card-back .fc-card-text {
        font-size: 1rem;
    }
    
    .fc-nav-btn {
        min-width: 110px;
    }
    
    .fc-keyboard-hint {
        display: none;
    }
}