/* --- CSS Variables (Color Palette) --- */
html {
    overflow-y: scroll;
}

:root {
    --color-primary: #4f6dff;
    --color-primary-light: #2a3b7d;
    --color-primary-dark: #3a5bf0;
    --color-secondary: #ffcd1f; 
    
    --color-bg: #0a092b; 
    --color-bg-secondary: #1a2342; 
    --color-card-bg: #232e54; 
    --color-text-primary: #ffffff; 
    --color-text-secondary: #cbd5e1; /* Slightly brighter for better contrast */
    --color-border: #3a497c;
    
    --color-correct: #38c172;
    --color-correct-bg: rgba(56, 193, 114, 0.15);
    --color-incorrect: #e3342f;
    --color-incorrect-bg: rgba(227, 52, 47, 0.15);

    --shadow-sm: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.25);
    --shadow-lg: 0 10px 30px rgba(0,0,0,0.4);
    
    --border-radius-button: 12px;
}

body.light-mode {
    --color-primary: #4257b2;
    --color-primary-light: #f0f3ff;
    --color-primary-dark: #3a4b99;
    --color-secondary: #f2b000;
    
    --color-bg: #f6f7fb;
    --color-bg-secondary: #ffffff;
    --color-card-bg: #ffffff;
    --color-text-primary: #1e293b;
    --color-text-secondary: #64748b;
    --color-border: #e2e8f0;
    
    --color-correct: #16a34a;
    --color-incorrect: #dc2626;
    
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
}

body {
    background-color: var(--color-bg);
    color: var(--color-text-primary);
    font-family: 'Inter', sans-serif;
    transition: background-color 0.3s ease, color 0.3s ease;
    -webkit-font-smoothing: antialiased;
    /* Prevent selection of text globally for study helper */
    user-select: none;
    -webkit-user-select: none;
}

/* Allow selection in inputs */
input, textarea, [contenteditable] {
    user-select: text;
    -webkit-user-select: text;
}

/* --- Common UI --- */
.app-view { display: none; animation: fadeIn 0.4s cubic-bezier(0.16, 1, 0.3, 1); }

@keyframes fadeIn { 
    from { opacity: 0; transform: translateY(15px); } 
    to { opacity: 1; transform: translateY(0); } 
}

@keyframes popIn {
    0% { transform: scale(0.95); opacity: 0; }
    100% { transform: scale(1); opacity: 1; }
}

.animate-pop {
    animation: popIn 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

/* --- Header Logo --- */
#header-logo {
    left: 50%;
    transform: translateX(-50%);
    width: 48px;
    height: 48px;
    transition: all 0.3s ease;
    border-radius: 50%;
    box-shadow: var(--shadow-md);
}
#header-logo:hover {
    transform: translateX(-50%) scale(1.05);
    box-shadow: var(--shadow-lg);
}

/* --- Buttons --- */
.nav-button {
    background: transparent;
    color: var(--color-text-secondary);
    font-weight: 700;
    padding: 0.75rem 1.25rem;
    transition: all 0.2s ease;
    border-bottom: 3px solid transparent;
}
.nav-button:hover {
    color: var(--color-text-primary);
    background-color: rgba(128, 128, 128, 0.05);
}
.nav-button.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
    background-color: transparent;
}
/* Special style for Share button to stand out */
.nav-button.share-button {
    color: var(--color-primary);
    border: 1px solid var(--color-primary);
    border-bottom-width: 1px;
    padding: 0.5rem 1rem;
    margin-left: 0.5rem;
}
.nav-button.share-button:hover {
    background-color: var(--color-primary);
    color: white;
}

.main-action-button {
    background-color: var(--color-primary);
    color: white;
    border-radius: var(--border-radius-button);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}
.main-action-button:hover { 
    background-color: var(--color-primary-dark); 
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}
.main-action-button:active {
    transform: translateY(0);
}

.secondary-action-button {
    background-color: var(--color-card-bg);
    color: var(--color-text-secondary);
    border: 2px solid var(--color-border);
    border-radius: var(--border-radius-button);
    font-weight: 700;
    transition: all 0.2s ease;
}
.secondary-action-button:hover {
    border-color: var(--color-text-secondary);
    color: var(--color-text-primary);
    background-color: var(--color-bg-secondary);
}
.secondary-action-button.active {
    border-color: var(--color-primary);
    color: var(--color-primary);
    background-color: rgba(79, 109, 255, 0.1);
}

.danger-action-button {
    background-color: transparent;
    color: var(--color-incorrect);
    border: 1px solid var(--color-incorrect);
    border-radius: var(--border-radius-button);
    transition: all 0.2s ease;
}
.danger-action-button:hover {
    background-color: var(--color-incorrect);
    color: white;
}

.nav-arrow-button {
    background: var(--color-card-bg);
    border: 1px solid var(--color-border);
    border-radius: 50%;
    width: 44px;
    height: 44px;
    color: var(--color-text-primary);
    font-size: 1.25rem;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
}
.nav-arrow-button:hover {
    border-color: var(--color-primary);
    background: var(--color-bg-secondary);
    color: var(--color-primary);
    transform: scale(1.05);
}

.create-toggle-button {
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-weight: 600;
    color: var(--color-text-secondary);
    background: transparent;
    border: 1px solid transparent;
    transition: all 0.2s;
}
.create-toggle-button.active {
    background-color: var(--color-card-bg);
    color: var(--color-primary);
    border-color: var(--color-border);
    font-weight: 700;
    box-shadow: var(--shadow-sm);
}

/* --- Create Mode --- */
.passage-editor-row {
    background-color: var(--color-card-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-button);
    padding: 1.5rem;
    cursor: grab;
    transition: box-shadow 0.2s, transform 0.2s;
}
.passage-editor-row:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--color-text-secondary);
}
.passage-editor-row.dragging { 
    opacity: 0.8; 
    border: 2px dashed var(--color-primary); 
    transform: scale(1.02);
    box-shadow: var(--shadow-lg);
    z-index: 10;
}

/* --- Reveal Mode Styles --- */
#reveal-container {
    background-color: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
}

.reveal-line {
    transition: all 0.6s cubic-bezier(0.16, 1, 0.3, 1);
    padding: 6px 10px;
    border-radius: 6px;
    cursor: pointer;
    /* Ensure clean rendering */
    transform-origin: left center;
    backface-visibility: hidden;
    /* Important: Preserves spaces so hints for indentation are visible */
    white-space: pre-wrap;
}

.reveal-line.hidden .reveal-hidden-part {
    /* The "Pristine" Blur Effect */
    filter: blur(8px);
    opacity: 0.3;
    user-select: none;
    transform: scale(0.99);
    display: inline-block;
}
.reveal-line.hidden:hover {
    opacity: 0.8; /* Hint that it's interactive */
}

.reveal-line.visible {
    opacity: 1;
    cursor: text;
    background-color: transparent;
}
.reveal-line.visible .reveal-hidden-part {
    filter: blur(0);
    opacity: 1;
}

/* Updated Reveal Mode Buttons (Sleeker Look) */
#reveal-line-button, #reveal-show-all, #reveal-hide-all {
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-size: 0.85rem;
    padding: 0.75rem 1.5rem;
    border-radius: 8px; /* Slightly tighter radius for a sleeker feel */
    font-weight: 800;
    box-shadow: var(--shadow-sm);
}
#reveal-line-button {
    /* Primary Action */
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
}
#reveal-show-all, #reveal-hide-all {
    /* Secondary Actions */
    padding: 0.75rem 1rem;
    font-size: 0.75rem;
}

/* --- Type Mode Styles --- */
#type-input-area {
    background: rgba(0,0,0,0.02); /* Very subtle tint */
    color: var(--color-text-primary);
    caret-color: var(--color-primary);
}
#type-ghost-overlay {
    color: var(--color-text-secondary);
    letter-spacing: normal;
    font-family: monospace; /* Ensure absolute alignment */
}

/* New Diff Feedback Styles */
.type-diff-word-group {
    display: inline-block; /* Keep words grouped */
    margin-right: 0.2em;
}
.type-diff-correct {
    color: var(--color-correct);
}
.type-diff-incorrect {
    color: var(--color-incorrect);
    text-decoration: underline wavy var(--color-incorrect);
}
.type-diff-missing {
    color: var(--color-text-secondary);
    opacity: 0.5;
}


/* --- Order Mode Styles --- */
.order-item {
    background-color: var(--color-card-bg);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 1.25rem;
    cursor: grab;
    transition: all 0.2s cubic-bezier(0.2, 0, 0, 1);
    font-weight: 500;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    box-shadow: var(--shadow-sm);
}
/* Add a handle icon via CSS */
.order-item::before {
    content: "⋮⋮";
    color: var(--color-border);
    font-weight: 900;
    letter-spacing: 2px;
    font-size: 1.2rem;
}

.order-item:hover {
    border-color: var(--color-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}
.order-item.dragging {
    opacity: 0.9;
    background-color: var(--color-bg-secondary);
    border: 2px dashed var(--color-primary);
    box-shadow: var(--shadow-lg);
    cursor: grabbing;
}
.order-item.correct {
    border-color: var(--color-correct);
    background-color: var(--color-correct-bg);
    color: var(--color-correct);
}
.order-item.incorrect {
    border-color: var(--color-incorrect);
    background-color: var(--color-incorrect-bg);
    color: var(--color-incorrect);
}

/* --- Toast --- */
#toast-notification {
    background-color: var(--color-bg-secondary);
    color: var(--color-text-primary);
    border: 1px solid var(--color-border);
}
#toast-notification.show { opacity: 1; transform: translateY(0); }

/* --- Modals --- */
#about-modal-overlay.visible, #keybinds-modal-overlay.visible, #clear-confirm-modal-overlay.visible {
    visibility: visible; 
    opacity: 1;
    pointer-events: auto;
}
#about-modal-overlay.visible #about-modal-content, 
#keybinds-modal-overlay.visible #keybinds-modal-content,
#clear-confirm-modal-overlay.visible #clear-confirm-modal-content {
    transform: scale(1);
}