/* ==========================================================================
   WordFlow - Design System & Stylesheet (Palette A: Indigo & Violet)
   ========================================================================== */

/* --- Base Custom Properties & Colors --- */
:root {
    /* Fonts */
    --font-primary: 'Inter', system-ui, -apple-system, sans-serif;
    --font-heading: 'Outfit', var(--font-primary);

    /* Animation Timing */
    --transition-slow: 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    --transition-medium: 0.25s cubic-bezier(0.16, 1, 0.3, 1);
    --transition-fast: 0.15s ease;

    /* Semantic Colors (Shared) */
    --color-success: #10b981;      /* Emerald Green */
    --color-success-rgb: 16, 185, 129;
    --color-danger: #ef4444;       /* Rose Red */
    --color-danger-rgb: 239, 68, 68;
    --color-warning: #f59e0b;      /* Amber Orange */
    --color-info: #3b82f6;         /* Blue */

    /* Scrollbar */
    color-scheme: dark light;
}

/* --- Dark Theme Variables (Default) --- */
.dark-theme {
    --bg-gradient: radial-gradient(circle at 50% 0%, #1e1b4b 0%, #0f172a 60%, #020617 100%);
    --bg-color: #090d1a;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;

    /* Brand Gradients (Indigo / Violet) */
    --primary: #6366f1;
    --primary-rgb: 99, 102, 241;
    --primary-glow: rgba(99, 102, 241, 0.35);
    --primary-hover: #4f46e5;
    
    --secondary: #a855f7;
    --secondary-hover: #9333ea;
    
    --gradient-brand: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #d946ef 100%);
    --gradient-glow: linear-gradient(135deg, rgba(99,102,241,0.2) 0%, rgba(139,92,246,0.2) 100%);

    /* Glassmorphism Values */
    --glass-bg: rgba(15, 23, 42, 0.55);
    --glass-border: rgba(255, 255, 255, 0.08);
    --glass-shadow: rgba(0, 0, 0, 0.35);
    --glass-blur: 16px;

    /* Card Details */
    --card-bg-hover: rgba(255, 255, 255, 0.02);
    --border-color: rgba(255, 255, 255, 0.08);
    --input-bg: rgba(2, 6, 17, 0.6);
    --input-border: rgba(255, 255, 255, 0.12);
    --input-focus-border: #6366f1;
}

/* --- Light Theme Variables --- */
.light-theme {
    --bg-gradient: radial-gradient(circle at 50% 0%, #eef2ff 0%, #f8fafc 70%, #f1f5f9 100%);
    --bg-color: #f8fafc;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;

    /* Brand Gradients (Indigo / Violet) */
    --primary: #4f46e5;
    --primary-rgb: 79, 70, 229;
    --primary-glow: rgba(79, 70, 229, 0.15);
    --primary-hover: #3730a3;
    
    --secondary: #9333ea;
    --secondary-hover: #7e22ce;
    
    --gradient-brand: linear-gradient(135deg, #4f46e5 0%, #7c3aed 50%, #c084fc 100%);
    --gradient-glow: linear-gradient(135deg, rgba(79,70,229,0.08) 0%, rgba(124,58,237,0.08) 100%);

    /* Glassmorphism Values */
    --glass-bg: rgba(255, 255, 255, 0.65);
    --glass-border: rgba(79, 70, 229, 0.08);
    --glass-shadow: rgba(31, 38, 135, 0.06);
    --glass-blur: 12px;

    /* Card Details */
    --card-bg-hover: rgba(79, 70, 229, 0.02);
    --border-color: rgba(79, 70, 229, 0.1);
    --input-bg: rgba(255, 255, 255, 0.9);
    --input-border: rgba(79, 70, 229, 0.18);
    --input-focus-border: #4f46e5;
}

/* --- Reset & Base Setup --- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-primary);
    background: var(--bg-color);
    background-image: var(--bg-gradient);
    background-attachment: fixed;
    color: var(--text-primary);
    min-height: 100vh;
    padding-bottom: 3rem;
    transition: background-color var(--transition-slow), color var(--transition-medium);
    overflow-x: hidden;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 99px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.25;
}

a {
    color: var(--primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}
a:hover {
    color: var(--primary-hover);
}

/* --- Common UI Components --- */

/* Glassmorphism Card Style */
.glass-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    box-shadow: 0 8px 32px var(--glass-shadow);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    transition: transform var(--transition-medium), box-shadow var(--transition-medium), border-color var(--transition-medium);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: 10px;
    font-family: var(--font-primary);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    border: 1px solid transparent;
    transition: all var(--transition-medium);
    user-select: none;
    outline: none;
}

.btn-primary {
    background: var(--gradient-brand);
    color: #ffffff;
    box-shadow: 0 4px 15px var(--primary-glow);
}
.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.45);
    filter: brightness(1.1);
}
.btn-primary:active {
    transform: translateY(0);
}

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

.btn-danger {
    background: var(--color-danger);
    color: #ffffff;
    box-shadow: 0 4px 12px rgba(239, 68, 68, 0.2);
}
.btn-danger:hover {
    background: #dc2626;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(239, 68, 68, 0.35);
}

.btn-success {
    background: var(--color-success);
    color: #ffffff;
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.2);
}
.btn-success:hover {
    background: #059669;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(16, 185, 129, 0.35);
}

.btn-glow {
    position: relative;
    overflow: hidden;
}
.btn-glow::after {
    content: '';
    position: absolute;
    top: 0;
    left: -50%;
    width: 200%;
    height: 100%;
    background: linear-gradient(to right, transparent, rgba(255, 255, 255, 0.25), transparent);
    transform: skewX(-30deg);
    transition: 0.75s;
    opacity: 0;
}
.btn-glow:hover::after {
    left: 125%;
    opacity: 1;
    transition: 0.75s ease-in-out;
}

.btn-text {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-weight: 500;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    border-radius: 8px;
    transition: all var(--transition-fast);
}
.btn-text:hover {
    color: var(--text-primary);
    background: var(--border-color);
}

.btn-large {
    padding: 14px 28px;
    font-size: 1.05rem;
    border-radius: 12px;
}

/* Badges / Chips */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 4px 10px;
    border-radius: 99px;
    font-size: 0.78rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    text-transform: uppercase;
}

.badge-learning {
    background: rgba(245, 158, 11, 0.12);
    color: var(--color-warning);
    border: 1px solid rgba(245, 158, 11, 0.25);
}
.badge-review {
    background: rgba(59, 130, 246, 0.12);
    color: var(--color-info);
    border: 1px solid rgba(59, 130, 246, 0.25);
}
.badge-mastered {
    background: rgba(16, 185, 129, 0.12);
    color: var(--color-success);
    border: 1px solid rgba(16, 185, 129, 0.25);
}

/* Form Elements */
.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 16px;
}
.form-row {
    display: flex;
    gap: 16px;
}
.flex-1 {
    flex: 1;
}

label {
    font-size: 0.88rem;
    font-weight: 600;
    color: var(--text-secondary);
}
.label-hint {
    font-size: 0.78rem;
    color: var(--text-muted);
    font-weight: 400;
}
.required {
    color: var(--color-danger);
}

input[type="text"],
select,
textarea {
    width: 100%;
    padding: 12px 16px;
    background: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: 10px;
    font-family: var(--font-primary);
    font-size: 0.95rem;
    color: var(--text-primary);
    outline: none;
    transition: all var(--transition-medium);
}
input[type="text"]:focus,
select:focus,
textarea:focus {
    border-color: var(--input-focus-border);
    box-shadow: 0 0 0 3px var(--primary-glow);
    background: var(--glass-bg);
}
textarea {
    resize: vertical;
}

/* Utility layout helper */
.hidden {
    display: none !important;
}
.mt-4 { margin-top: 1.5rem !important; }
.w-full { width: 100% !important; }
.danger-text { color: var(--color-danger) !important; }

/* ==========================================================================
   LAYOUT STRUCTURE
   ========================================================================== */

/* --- App Header --- */
.app-header {
    position: sticky;
    top: 0;
    z-index: 50;
    width: 100%;
    background: rgba(var(--primary-rgb), 0.02);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-color);
}
.header-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 24px;
}

.logo-area {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
}
.logo-icon {
    width: 28px;
    height: 28px;
    color: var(--primary);
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    filter: drop-shadow(0 2px 8px var(--primary-glow));
}
.logo-text {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 800;
    background: var(--gradient-brand);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.app-nav {
    display: flex;
    gap: 8px;
    background: var(--border-color);
    padding: 4px;
    border-radius: 12px;
}
.nav-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition-fast);
}
.nav-btn:hover {
    color: var(--text-primary);
}
.nav-btn.active {
    background: var(--glass-bg);
    color: var(--primary);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.theme-toggle-btn {
    background: var(--border-color);
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-fast);
}
.theme-toggle-btn:hover {
    transform: scale(1.05);
    background: var(--primary-glow);
    color: var(--primary);
}
.sun-icon { display: none; }
.moon-icon { display: block; }
.dark-theme .sun-icon { display: block; }
.dark-theme .moon-icon { display: none; }

/* --- Main Views Section --- */
.main-content {
    max-width: 1200px;
    margin: 32px auto 0 auto;
    padding: 0 24px;
}

.app-view {
    display: none;
    animation: fadeIn var(--transition-medium) forwards;
}
.app-view.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ==========================================================================
   VIEW 1: DASHBOARD VIEW
   ========================================================================== */

/* Stats Summary Panel */
.stats-panel {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
    padding: 20px 24px;
    margin-bottom: 24px;
}
.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}
.stat-value {
    font-family: var(--font-heading);
    font-size: 2rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 4px;
}
.stat-label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.stat-item.learning .stat-value { color: var(--color-warning); }
.stat-item.review .stat-value { color: var(--color-info); }
.stat-item.mastered .stat-value { color: var(--color-success); }

/* Search & Filter Controls */
.controls-panel {
    padding: 24px;
    margin-bottom: 32px;
}
.search-wrapper {
    position: relative;
    width: 100%;
    margin-bottom: 20px;
}
.search-icon {
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    pointer-events: none;
}
.search-wrapper input {
    padding-left: 48px;
    font-size: 1.05rem;
    border-radius: 12px;
}

.filters-row {
    display: flex;
    align-items: flex-end;
    gap: 16px;
    flex-wrap: wrap;
}
.filters-row .filter-group {
    flex: 1;
    min-width: 180px;
    margin-bottom: 0;
}
.btn-add {
    height: 46px;
    min-width: 140px;
}

/* Quick Filter Tags */
.tags-quick-filter {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}
.tags-filter-title {
    font-size: 0.82rem;
    font-weight: 700;
    color: var(--text-muted);
}
.tags-filter-list {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    align-items: center;
}
.tag-filter-btn {
    background: var(--border-color);
    border: none;
    color: var(--text-secondary);
    padding: 4px 12px;
    border-radius: 99px;
    font-size: 0.78rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}
.tag-filter-btn:hover {
    color: var(--text-primary);
    background: var(--primary-glow);
}
.tag-filter-btn.active {
    background: var(--gradient-brand);
    color: #ffffff;
    box-shadow: 0 2px 8px var(--primary-glow);
}

/* Expressions Grid & Card Styling */
.expressions-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 24px;
}

.expression-card {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    height: 100%;
    padding: 24px;
    position: relative;
    overflow: hidden;
}
.expression-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: var(--border-color);
    transition: background var(--transition-medium);
}
.expression-card.learning::before { background: var(--color-warning); }
.expression-card.review::before { background: var(--color-info); }
.expression-card.mastered::before { background: var(--color-success); }

.expression-card:hover {
    transform: translateY(-4px);
    background: var(--card-bg-hover);
    box-shadow: 0 12px 40px var(--glass-shadow);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 12px;
    margin-bottom: 14px;
}
.source-pill {
    background: var(--border-color);
    color: var(--text-secondary);
    padding: 2px 10px;
    border-radius: 99px;
    font-size: 0.75rem;
    font-weight: 600;
    max-width: 180px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* Card content */
.card-content-area {
    margin-bottom: 20px;
    flex-grow: 1;
}
.card-english {
    font-size: 1.2rem;
    font-weight: 700;
    font-family: var(--font-heading);
    color: var(--text-primary);
    line-height: 1.4;
    margin-bottom: 8px;
    word-break: break-word;
}
.card-japanese {
    font-size: 0.92rem;
    color: var(--text-secondary);
    line-height: 1.5;
    margin-bottom: 12px;
    word-break: break-word;
}

/* Card details optional */
.card-details-divider {
    border: none;
    height: 1px;
    background: var(--border-color);
    margin: 10px 0;
}
.card-notes {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-style: italic;
    background: rgba(var(--primary-rgb), 0.03);
    padding: 6px 10px;
    border-radius: 6px;
    margin-top: 6px;
    word-break: break-word;
}

/* Card footer details */
.card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 12px;
    border-top: 1px solid var(--border-color);
}
.card-keyword-pill {
    background: rgba(139, 92, 246, 0.08);
    color: var(--secondary);
    border: 1px solid rgba(139, 92, 246, 0.2);
    padding: 2px 10px;
    border-radius: 99px;
    font-size: 0.78rem;
    font-weight: 700;
    cursor: pointer;
    transition: all var(--transition-fast);
}
.card-keyword-pill:hover {
    background: var(--gradient-brand);
    color: #ffffff;
}

.card-actions {
    display: flex;
    gap: 4px;
}
.card-action-btn {
    background: transparent;
    border: none;
    width: 32px;
    height: 32px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    cursor: pointer;
    transition: all var(--transition-fast);
}
.card-action-btn:hover {
    background: var(--border-color);
    color: var(--text-primary);
}
.card-action-btn.btn-delete-card:hover {
    color: var(--color-danger);
    background: rgba(239, 68, 68, 0.1);
}

/* Empty State Styling */
.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 80px 24px;
    background: var(--glass-bg);
    border: 1px dashed var(--border-color);
    border-radius: 20px;
}
.empty-icon {
    width: 64px;
    height: 64px;
    color: var(--text-muted);
    margin-bottom: 20px;
    opacity: 0.6;
}
.empty-state h3 {
    font-size: 1.35rem;
    margin-bottom: 8px;
    font-family: var(--font-heading);
}
.empty-state p {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-bottom: 24px;
}

/* ==========================================================================
   VIEW 2: REVIEW MODE
   ========================================================================== */

/* Review Setup Form Card */
.review-setup {
    max-width: 680px;
    margin: 0 auto;
    padding: 36px;
}
.review-setup h2 {
    font-size: 1.8rem;
    font-family: var(--font-heading);
    margin-bottom: 8px;
    text-align: center;
}
.setup-subtitle {
    color: var(--text-secondary);
    text-align: center;
    margin-bottom: 32px;
    font-size: 0.95rem;
}
.setup-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}
.setup-actions {
    display: flex;
    justify-content: center;
    margin-top: 12px;
}
.setup-actions button {
    width: 100%;
    max-width: 280px;
}

/* Active Review Session Container */
.review-session {
    max-width: 760px;
    margin: 0 auto;
}
.review-progress-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}
.progress-info {
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--text-secondary);
}

.progress-bar-container {
    width: 100%;
    height: 6px;
    background: var(--border-color);
    border-radius: 99px;
    margin-bottom: 28px;
    overflow: hidden;
}
.progress-bar-fill {
    height: 100%;
    background: var(--gradient-brand);
    border-radius: 99px;
    transition: width var(--transition-medium);
    box-shadow: 0 0 8px var(--primary-glow);
}

/* Main Review Card */
.review-card {
    padding: 40px;
    position: relative;
    margin-bottom: 24px;
}
.review-meta {
    display: flex;
    gap: 8px;
    margin-bottom: 24px;
}
.meta-badge {
    padding: 4px 10px;
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 600;
}
.source-badge {
    background: var(--border-color);
    color: var(--text-secondary);
}
.keyword-badge {
    background: rgba(139, 92, 246, 0.08);
    color: var(--secondary);
    border: 1px solid rgba(139, 92, 246, 0.2);
}

.review-question-area {
    margin-bottom: 32px;
}
.japanese-translation {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.5;
    word-break: break-word;
}

.review-typing-area {
    margin-bottom: 32px;
}
.english-expression-blank {
    font-size: 1.5rem;
    font-weight: 600;
    font-family: var(--font-heading);
    line-height: 1.8;
    color: var(--text-primary);
    background: rgba(var(--primary-rgb), 0.02);
    border: 1px solid var(--border-color);
    padding: 20px 24px;
    border-radius: 12px;
    word-break: break-word;
}

/* Styling for the dynamically generated blank input inside the English text */
.typing-blank-input {
    display: inline-block;
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 1.45rem;
    text-align: center;
    border: none;
    border-bottom: 3px dashed var(--text-muted);
    background: rgba(var(--primary-rgb), 0.08);
    color: var(--primary);
    padding: 0 8px;
    margin: 0 4px;
    outline: none;
    border-radius: 4px;
    transition: all var(--transition-fast);
    width: 140px; /* modified by JS based on length */
}
.typing-blank-input:focus {
    border-bottom-style: solid;
    border-bottom-color: var(--primary);
    background: rgba(var(--primary-rgb), 0.15);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}

/* Validation Feedback States */
.typing-blank-input.correct {
    border-bottom-color: var(--color-success) !important;
    border-bottom-style: solid !important;
    color: var(--color-success) !important;
    background: rgba(16, 185, 129, 0.12) !important;
    box-shadow: 0 0 16px rgba(16, 185, 129, 0.25) !important;
}

.typing-blank-input.incorrect {
    border-bottom-color: var(--color-danger) !important;
    border-bottom-style: solid !important;
    color: var(--color-danger) !important;
    background: rgba(239, 68, 68, 0.12) !important;
    box-shadow: 0 0 16px rgba(239, 68, 68, 0.25) !important;
}

/* Shake Animation Keyframes */
@keyframes shake {
    0%, 100% { transform: translateX(0); }
    20%, 60% { transform: translateX(-8px); }
    40%, 80% { transform: translateX(8px); }
}
.shake-element {
    animation: shake 0.35s ease-in-out;
}

/* Card Notes Section in Review Card */
.review-note-area {
    margin-bottom: 32px;
    padding: 16px 20px;
    background: rgba(59, 130, 246, 0.05);
    border-left: 4px solid var(--color-info);
    border-radius: 0 8px 8px 0;
    animation: slideDown var(--transition-medium) forwards;
}
@keyframes slideDown {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}
.review-note-area .note-content {
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

/* Labels */
.review-card .label {
    display: block;
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 8px;
}

/* Feedback Box */
.review-feedback {
    margin-bottom: 24px;
    animation: fadeIn var(--transition-fast) forwards;
}
.feedback-card {
    padding: 14px 20px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 600;
}
.feedback-card.correct {
    background: rgba(16, 185, 129, 0.12);
    color: var(--color-success);
    border: 1px solid rgba(16, 185, 129, 0.2);
}
.feedback-card.incorrect {
    background: rgba(239, 68, 68, 0.12);
    color: var(--color-danger);
    border: 1px solid rgba(239, 68, 68, 0.2);
}
.feedback-icon {
    width: 20px;
    height: 20px;
}

/* Review Bottom Buttons */
.review-actions {
    display: flex;
    justify-content: flex-end;
    gap: 12px;
    border-top: 1px solid var(--border-color);
    padding-top: 24px;
}
.review-actions button {
    min-width: 120px;
}
#btn-next-question {
    min-width: 160px;
}

/* Summary Card Result */
.review-summary {
    max-width: 580px;
    margin: 0 auto;
}
.summary-card {
    padding: 48px;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
}
.celebration-icon {
    width: 80px;
    height: 80px;
    border-radius: 99px;
    background: rgba(139, 92, 246, 0.1);
    color: var(--secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
    box-shadow: 0 4px 20px rgba(139, 92, 246, 0.2);
}
.summary-card h2 {
    font-size: 1.8rem;
    font-family: var(--font-heading);
    margin-bottom: 8px;
}
.summary-text {
    color: var(--text-secondary);
    margin-bottom: 32px;
}
.score-display {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 4px;
    margin-bottom: 32px;
}
.score-num {
    font-family: var(--font-heading);
    font-size: 4rem;
    font-weight: 800;
    color: var(--primary);
    line-height: 1;
}
.score-slash {
    font-size: 2rem;
    color: var(--text-muted);
}
.score-denom {
    font-family: var(--font-heading);
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--text-secondary);
}
.score-percent {
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--text-muted);
    margin-left: 12px;
}

.summary-details {
    display: flex;
    gap: 32px;
    margin-bottom: 40px;
    background: var(--border-color);
    padding: 16px 36px;
    border-radius: 12px;
}
.summary-detail-item {
    display: flex;
    flex-direction: column;
    align-items: center;
}
.summary-detail-item .num {
    font-size: 1.5rem;
    font-weight: 800;
    font-family: var(--font-heading);
}
.summary-detail-item .num.green { color: var(--color-success); }
.summary-detail-item .num.orange { color: var(--color-warning); }
.summary-detail-item .lbl {
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-top: 4px;
}

.summary-actions {
    display: flex;
    gap: 16px;
    width: 100%;
}
.summary-actions button {
    flex: 1;
}

/* ==========================================================================
   VIEW 3: SETTINGS & BACKUP VIEW
   ========================================================================== */

.settings-container {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 32px;
}
.settings-card {
    padding: 32px;
}
.settings-card h2 {
    font-size: 1.4rem;
    font-family: var(--font-heading);
    margin-bottom: 8px;
}
.settings-desc {
    font-size: 0.92rem;
    color: var(--text-secondary);
    margin-bottom: 24px;
    line-height: 1.5;
}

.settings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}
.settings-action-box {
    background: rgba(var(--primary-rgb), 0.02);
    border: 1px solid var(--border-color);
    padding: 24px;
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}
.settings-action-box h3 {
    font-size: 1.05rem;
    margin-bottom: 8px;
}
.settings-action-box p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.5;
    margin-bottom: 20px;
    flex-grow: 1;
}

.maintenance-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 24px;
    flex-wrap: wrap;
}
.maintenance-item h3 {
    font-size: 1.05rem;
    margin-bottom: 4px;
}
.maintenance-item p {
    font-size: 0.85rem;
    color: var(--text-muted);
}
.settings-divider {
    border: none;
    height: 1px;
    background: var(--border-color);
    margin: 20px 0;
}

/* Guidance Tips Box */
.info-card {
    background: var(--gradient-glow);
    border-color: rgba(99, 102, 241, 0.15);
}
.info-card h3 {
    color: var(--primary);
    font-size: 1.1rem;
    margin-bottom: 8px;
}
.info-card p {
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.5;
    margin-bottom: 12px;
}
.info-card ul {
    padding-left: 20px;
    margin-bottom: 12px;
}
.info-card li {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 6px;
}
.guide-note {
    font-style: italic;
    color: var(--text-muted) !important;
}

/* ==========================================================================
   MODAL WINDOW STYLES
   ========================================================================== */

.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(2, 6, 17, 0.65);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    padding: 20px;
    animation: fadeInBg var(--transition-fast) forwards;
}
@keyframes fadeInBg {
    from { opacity: 0; }
    to { opacity: 1; }
}

.modal-container {
    width: 100%;
    max-width: 640px;
    max-height: 90vh;
    overflow-y: auto;
    padding: 32px;
    animation: scaleIn var(--transition-medium) forwards;
}
.modal-small {
    max-width: 480px;
}
@keyframes scaleIn {
    from { opacity: 0; transform: scale(0.95); }
    to { opacity: 1; transform: scale(1); }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}
.modal-header h2 {
    font-size: 1.45rem;
    font-family: var(--font-heading);
}
.modal-close {
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    width: 32px;
    height: 32px;
    border-radius: 99px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}
.modal-close:hover {
    background: var(--border-color);
    color: var(--text-primary);
}

.modal-form {
    display: flex;
    flex-direction: column;
    gap: 18px;
}

.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: 12px;
    margin-top: 12px;
    border-top: 1px solid var(--border-color);
    padding-top: 20px;
}
.form-actions button {
    min-width: 110px;
}

/* Entry validation error alert block */
.form-error-alert {
    display: flex;
    align-items: center;
    gap: 8px;
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.25);
    color: var(--color-danger);
    padding: 10px 14px;
    border-radius: 8px;
    font-size: 0.88rem;
    font-weight: 500;
}

/* Custom import actions grid */
.modal-actions-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}
.modal-actions-grid button {
    text-align: left;
    padding: 20px;
    background: rgba(var(--primary-rgb), 0.02);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    cursor: pointer;
    transition: all var(--transition-medium);
    outline: none;
}
.modal-actions-grid button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}
.modal-actions-grid button h3 {
    font-size: 1.05rem;
    margin-bottom: 4px;
}
.modal-actions-grid button p {
    font-size: 0.8rem;
    color: var(--text-secondary);
    line-height: 1.4;
}
.modal-actions-grid #btn-import-merge:hover {
    border-color: var(--primary);
    background: rgba(var(--primary-rgb), 0.05);
}
.modal-actions-grid #btn-import-overwrite:hover {
    border-color: var(--color-danger);
    background: rgba(239, 68, 68, 0.05);
}

.import-stats-preview {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    background: var(--border-color);
    padding: 8px 12px;
    border-radius: 6px;
    display: inline-block;
}

/* ==========================================================================
   TOAST NOTIFICATION (FLAT & MINIMAL)
   ========================================================================== */

.toast-notification {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(0);
    background: #0f172a;
    color: #f8fafc;
    border: 1px solid rgba(255,255,255,0.12);
    padding: 12px 24px;
    border-radius: 10px;
    font-size: 0.9rem;
    font-weight: 600;
    z-index: 150;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.4);
    pointer-events: none;
    animation: toastIn var(--transition-medium) forwards;
}

@keyframes toastIn {
    from { opacity: 0; transform: translateX(-50%) translateY(20px); }
    to { opacity: 1; transform: translateX(-50%) translateY(0); }
}

/* ==========================================================================
   RESPONSIVE DESIGN ADAPTATIONS
   ========================================================================== */

@media (max-width: 900px) {
    .header-container {
        padding: 12px 16px;
    }
    .app-header {
        position: static; /* Let it scroll on small screens if layout is tight */
    }
    .logo-text {
        font-size: 1.35rem;
    }
    .stats-panel {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
        padding: 16px;
    }
    .expressions-grid {
        grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
        gap: 16px;
    }
}

@media (max-width: 768px) {
    .header-container {
        flex-direction: column;
        gap: 12px;
        align-items: center;
    }
    .header-actions {
        position: absolute;
        right: 16px;
        top: 10px;
    }
    .main-content {
        margin-top: 16px;
        padding: 0 16px;
    }
    .review-setup {
        padding: 24px 16px;
    }
    .review-card {
        padding: 24px;
    }
    .japanese-translation {
        font-size: 1.35rem;
    }
    .english-expression-blank {
        font-size: 1.25rem;
        padding: 16px;
    }
    .typing-blank-input {
        font-size: 1.2rem;
        width: 100px;
    }
    .score-display .score-num {
        font-size: 3rem;
    }
    .form-row {
        flex-direction: column;
        gap: 0;
    }
}

@media (max-width: 480px) {
    .app-nav {
        width: 100%;
        justify-content: space-between;
    }
    .nav-btn {
        padding: 8px 10px;
        font-size: 0.8rem;
        flex: 1;
        justify-content: center;
    }
    .nav-btn svg {
        width: 16px;
        height: 16px;
    }
    .filters-row {
        flex-direction: column;
        align-items: stretch;
    }
    .btn-add {
        width: 100%;
    }
    .review-actions {
        flex-direction: column;
        align-items: stretch;
    }
    .review-actions button {
        width: 100%;
    }
    .summary-actions {
        flex-direction: column;
        gap: 12px;
    }
    .modal-container {
        padding: 20px 16px;
    }
}