/* ===================================
   CSS Custom Properties (Design Tokens)
   =================================== */
:root {
    /* Colors - Premium Palette */
    --color-primary: #6366f1;
    --color-primary-light: #818cf8;
    --color-primary-dark: #4f46e5;
    --color-secondary: #ec4899;
    --color-secondary-light: #f472b6;
    --color-accent: #14b8a6;
    --color-accent-light: #2dd4bf;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-accent: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --gradient-warm: linear-gradient(135deg, #fa709a 0%, #fee140 100%);

    /* Neutrals */
    --color-bg: #0f172a;
    --color-bg-light: #1e293b;
    --color-bg-lighter: #334155;
    --color-surface: rgba(255, 255, 255, 0.05);
    --color-surface-hover: rgba(255, 255, 255, 0.08);
    --color-text: #f1f5f9;
    --color-text-secondary: #cbd5e1;
    --color-text-muted: #94a3b8;
    --color-border: rgba(255, 255, 255, 0.1);

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.4);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-full: 9999px;

    /* Typography */
    --font-sans: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===================================
   Reset & Base Styles
   =================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
}

/* ===================================
   Background Effects
   =================================== */
.bg-gradient {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 20% 20%, rgba(99, 102, 241, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(236, 72, 153, 0.15) 0%, transparent 50%);
    pointer-events: none;
    z-index: 0;
}

.bg-shapes {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    overflow: hidden;
    pointer-events: none;
    z-index: 0;
}

.shape {
    position: absolute;
    border-radius: 50%;
    filter: blur(60px);
    opacity: 0.3;
    animation: float 20s infinite ease-in-out;
}

.shape-1 {
    width: 300px;
    height: 300px;
    background: var(--gradient-primary);
    top: 10%;
    left: 10%;
    animation-delay: 0s;
}

.shape-2 {
    width: 400px;
    height: 400px;
    background: var(--gradient-secondary);
    bottom: 10%;
    right: 10%;
    animation-delay: 7s;
}

.shape-3 {
    width: 250px;
    height: 250px;
    background: var(--gradient-accent);
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation-delay: 14s;
}

@keyframes float {

    0%,
    100% {
        transform: translate(0, 0) scale(1);
    }

    33% {
        transform: translate(30px, -30px) scale(1.1);
    }

    66% {
        transform: translate(-20px, 20px) scale(0.9);
    }
}

/* ===================================
   Container
   =================================== */
.container {
    position: relative;
    z-index: 1;
    max-width: 800px;
    margin: 0 auto;
    padding: var(--spacing-lg);
    min-height: 100vh;
}

/* ===================================
   Header
   =================================== */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-2xl);
    padding: var(--spacing-lg);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(20px);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.logo i {
    font-size: var(--font-size-3xl);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo h1 {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header-stats {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.stat-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
    font-size: var(--font-size-sm);
}

.stat-item i {
    color: var(--color-accent);
    font-size: var(--font-size-lg);
}

.stat-item #dailyRemaining {
    font-weight: 700;
    font-size: var(--font-size-lg);
    color: var(--color-accent);
}

.stat-label {
    color: var(--color-text-muted);
}

/* Login & Profile */
.btn-login {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background: #07c160;
    /* WeChat Green */
    color: white;
    border: none;
    border-radius: var(--radius-full);
    font-size: var(--font-size-sm);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-base);
}

.btn-login:hover {
    background: #06ad56;
    transform: translateY(-1px);
}

.user-profile {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 4px;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
}

.user-avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--color-primary);
}

.user-name {
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-text);
    padding-right: var(--spacing-sm);
    max-width: 100px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* ===================================
   Buttons
   =================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: var(--font-size-base);
    font-weight: 600;
    border: none;
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    transform: translate(-50%, -50%);
    transition: width var(--transition-slow), height var(--transition-slow);
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.btn-secondary {
    background: var(--color-surface);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-surface-hover);
    border-color: var(--color-primary);
}

.btn-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    color: var(--color-text);
}

.btn-icon:hover {
    background: var(--color-surface-hover);
    border-color: var(--color-primary);
    color: var(--color-primary);
    transform: scale(1.05);
}

.btn-share {
    width: 100%;
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    background: var(--gradient-accent);
    color: white;
    border: none;
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-base);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.btn-share:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* ===================================
   Search Section
   =================================== */
.search-section {
    margin-bottom: var(--spacing-2xl);
}

.search-container {
    position: relative;
    margin-bottom: var(--spacing-lg);
}

.search-icon {
    position: absolute;
    left: var(--spacing-lg);
    top: 50%;
    transform: translateY(-50%);
    font-size: var(--font-size-xl);
    color: var(--color-text-muted);
    pointer-events: none;
}

.search-input {
    width: 100%;
    padding: var(--spacing-lg) var(--spacing-xl) var(--spacing-lg) 3.5rem;
    background: var(--color-surface);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-xl);
    color: var(--color-text);
    font-size: var(--font-size-lg);
    font-family: var(--font-sans);
    transition: all var(--transition-base);
    backdrop-filter: blur(20px);
}

.search-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
}

.search-input::placeholder {
    color: var(--color-text-muted);
}

.btn-clear {
    position: absolute;
    right: var(--spacing-md);
    top: 50%;
    transform: translateY(-50%);
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-surface-hover);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    color: var(--color-text-muted);
    transition: all var(--transition-fast);
}

.btn-clear:hover {
    background: var(--color-bg-lighter);
    color: var(--color-text);
}

/* ===================================
   Style Selector
   =================================== */
.style-selector {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: var(--spacing-sm);
}

.style-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-md);
    background: var(--color-surface);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all var(--transition-base);
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

.style-btn i {
    font-size: var(--font-size-2xl);
}

.style-btn:hover {
    background: var(--color-surface-hover);
    border-color: var(--color-primary-light);
    transform: translateY(-2px);
}

.style-btn.active {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.2) 0%, rgba(139, 92, 246, 0.2) 100%);
    border-color: var(--color-primary);
    color: var(--color-primary-light);
}

/* ===================================
   Memory Card
   =================================== */
.card-section {
    margin-bottom: var(--spacing-2xl);
}

.memory-card {
    perspective: 1000px;
    min-height: 500px;
}

.card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.6s;
    transform-style: preserve-3d;
}

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

.card-front,
.card-back {
    position: absolute;
    width: 100%;
    backface-visibility: hidden;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    backdrop-filter: blur(20px);
    box-shadow: var(--shadow-lg);
}

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

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-xl);
}

.word-title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-sm);
}

.word-pronunciation {
    color: var(--color-text-muted);
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-md);
}

.word-definition {
    font-size: var(--font-size-xl);
    color: var(--color-text-secondary);
    padding: var(--spacing-lg);
    background: var(--color-surface);
    border-left: 4px solid var(--color-primary);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-2xl);
}

.flip-hint {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    margin-top: var(--spacing-2xl);
    padding: var(--spacing-md);
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    animation: pulse 2s infinite;
}

@keyframes pulse {

    0%,
    100% {
        opacity: 0.6;
    }

    50% {
        opacity: 1;
    }
}

.section-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text);
}

.section-title i {
    color: var(--color-accent);
}

.mnemonic-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.mnemonic-section {
    padding: var(--spacing-lg);
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    border-left: 4px solid var(--color-accent);
}

.mnemonic-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-accent-light);
    margin-bottom: var(--spacing-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.mnemonic-text {
    color: var(--color-text-secondary);
    font-size: var(--font-size-base);
    line-height: 1.8;
}

.image-prompt {
    font-family: 'Courier New', monospace;
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    font-style: italic;
}

/* ===================================
   Action Buttons
   =================================== */
.action-buttons {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
}

/* ===================================
   Loading State
   =================================== */
.loading-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 400px;
}

.loading-spinner {
    text-align: center;
}

.spinner {
    width: 60px;
    height: 60px;
    margin: 0 auto var(--spacing-lg);
    border: 4px solid var(--color-surface);
    border-top: 4px solid var(--color-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}

.loading-text {
    color: var(--color-text-secondary);
    font-size: var(--font-size-lg);
    font-weight: 500;
}

/* ===================================
   Empty State
   =================================== */
.empty-state {
    text-align: center;
    padding: var(--spacing-2xl);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(20px);
}

.empty-icon {
    font-size: 80px;
    margin-bottom: var(--spacing-lg);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.empty-state h3 {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.empty-state p {
    color: var(--color-text-secondary);
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-xl);
}

.feature-list {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xl);
    flex-wrap: wrap;
}

.feature-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--color-text-muted);
}

.feature-item i {
    font-size: var(--font-size-2xl);
    color: var(--color-accent);
}

/* ===================================
   Modal
   =================================== */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: var(--spacing-lg);
}

.modal-content {
    background: var(--color-bg-light);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    max-width: 500px;
    width: 100%;
    box-shadow: var(--shadow-xl);
    animation: modalSlideIn 0.3s ease-out;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.modal-icon {
    font-size: 48px;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.modal-header h3 {
    font-size: var(--font-size-2xl);
    color: var(--color-text);
}

.modal-body {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.modal-body p {
    color: var(--color-text-secondary);
    font-size: var(--font-size-base);
    margin-bottom: var(--spacing-sm);
}

.modal-subtitle {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}

.modal-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

/* ===================================
   Side Panel
   =================================== */
.side-panel {
    position: fixed;
    top: 0;
    right: 0;
    width: 400px;
    max-width: 90vw;
    height: 100vh;
    background: var(--color-bg-light);
    border-left: 1px solid var(--color-border);
    z-index: 1000;
    transform: translateX(100%);
    transition: transform var(--transition-base);
    overflow-y: auto;
}

.side-panel.active {
    transform: translateX(0);
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-xl);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    background: var(--color-bg-light);
    z-index: 10;
}

.panel-header h3 {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-xl);
    color: var(--color-text);
}

.panel-content {
    padding: var(--spacing-lg);
}

.history-tabs {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.tab-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-md);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: all var(--transition-base);
}

.tab-btn:hover {
    background: var(--color-surface-hover);
}

.tab-btn.active {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: white;
}

.history-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

/* ===================================
   Overlay
   =================================== */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    z-index: 999;
    animation: fadeIn 0.2s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 768px) {
    .container {
        padding: var(--spacing-md);
    }

    .header {
        flex-direction: column;
        gap: var(--spacing-md);
        text-align: center;
    }

    .logo h1 {
        font-size: var(--font-size-xl);
    }

    .style-selector {
        grid-template-columns: repeat(2, 1fr);
    }

    .action-buttons {
        grid-template-columns: 1fr;
    }

    .modal-actions {
        grid-template-columns: 1fr;
    }

    .side-panel {
        width: 100%;
        max-width: 100%;
    }
}

/* ===================================
   Pronunciation Section
   =================================== */
.pronunciation-section {
    margin-top: var(--spacing-2xl);
    padding: var(--spacing-xl);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(20px);
}

.pronunciation-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.pronunciation-header i {
    font-size: var(--font-size-2xl);
    color: var(--color-secondary);
}

.pronunciation-header h4 {
    font-size: var(--font-size-xl);
    color: var(--color-text);
}

.pronunciation-controls {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.pronunciation-result {
    margin-top: var(--spacing-lg);
}

.score-display {
    display: flex;
    align-items: center;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: var(--color-surface);
    border-radius: var(--radius-lg);
}

.score-circle {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: var(--gradient-primary);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-glow);
    flex-shrink: 0;
}

.score-number {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: white;
    line-height: 1;
}

.score-label {
    font-size: var(--font-size-sm);
    color: rgba(255, 255, 255, 0.9);
}

.score-feedback {
    flex: 1;
}

.feedback-message {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
}

.encouragement {
    font-size: var(--font-size-base);
    color: var(--color-text-secondary);
}

.transcription-display {
    padding: var(--spacing-md);
    background: var(--color-surface);
    border-radius: var(--radius-md);
    border-left: 4px solid var(--color-secondary);
}

.transcription-display .label {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    margin-right: var(--spacing-xs);
}

.transcription-display .transcription {
    color: var(--color-text);
    font-weight: 600;
}

/* Recording button active state */
.btn.recording {
    background: var(--gradient-secondary);
    animation: recordPulse 1.5s infinite;
}

@keyframes recordPulse {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.8;
    }
}

/* ===================================
   Video Button
   =================================== */
.btn-video {
    width: 100%;
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    background: var(--gradient-warm);
    color: white;
    border: none;
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-base);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.btn-video:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-video:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* ===================================
   Utility Classes
   =================================== */
.hidden {
    display: none !important;
}

.visible {
    display: block !important;
}