/**
 * Main CSS - English Bubble Game
 * Global styles, colors, animations, responsive
 */

/* ================================
   CSS Variables - Color Palette
   ================================ */
:root {
    /* Primary colors */
    --blue-pastel: #7dd3fc;
    --purple-lavender: #c4b5fd;
    --pink-baby: #f9a8d4;
    --yellow-cream: #fde68a;
    --mint-green: #86efac;
    --white-glass: rgba(255, 255, 255, 0.72);
    --white-glass-strong: rgba(255, 255, 255, 0.85);
    
    /* Accent colors */
    --blue-dark: #0ea5e9;
    --purple-dark: #8b5cf6;
    --pink-dark: #ec4899;
    --orange-warm: #fb923c;
    --red-light: #fca5a5;
    
    /* Neutral */
    --gray-light: #f3f4f6;
    --gray-medium: #d1d5db;
    --gray-dark: #4b5563;
    --text-dark: #1f2937;
    
    /* Gradient backgrounds */
    --gradient-main: linear-gradient(135deg, #7dd3fc 0%, #c4b5fd 50%, #f9a8d4 100%);
    --gradient-purple: linear-gradient(135deg, #a78bfa 0%, #c4b5fd 50%, #f9a8d4 100%);
    --gradient-blue-pink: linear-gradient(135deg, #7dd3fc 0%, #f9a8d4 100%);
    
    /* Shadows */
    --shadow-soft: 0 10px 30px rgba(0, 0, 0, 0.1);
    --shadow-medium: 0 20px 50px rgba(0, 0, 0, 0.15);
    --shadow-strong: 0 30px 60px rgba(0, 0, 0, 0.2);
    
    /* Border radius */
    --radius-small: 12px;
    --radius-medium: 20px;
    --radius-large: 32px;
    --radius-xl: 40px;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Nunito', 'Fredoka', sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-dark);
    background: transparent;
    min-height: 100vh;
    overflow-x: hidden;
}

/* ================================
   Background Container
   ================================ */
.bg-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.gradient-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-main);
    animation: gradientShift 15s ease infinite;
}

@keyframes gradientShift {
    0%, 100% { filter: brightness(1) hue-rotate(0deg); }
    50% { filter: brightness(1.05) hue-rotate(5deg); }
}

.glow-top-left {
    position: absolute;
    top: -20%;
    left: -10%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(168, 85, 247, 0.3) 0%, transparent 70%);
    border-radius: 50%;
    filter: blur(60px);
}

.glow-bottom-right {
    position: absolute;
    bottom: -20%;
    right: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(236, 72, 153, 0.25) 0%, transparent 70%);
    border-radius: 50%;
    filter: blur(70px);
}

/* ================================
   Floating Bubbles Background
   ================================ */
.floating-bubbles {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
}

.bubble-bg {
    position: absolute;
    border-radius: 50%;
    background: radial-gradient(circle at 30% 30%, rgba(255, 255, 255, 0.6), rgba(255, 255, 255, 0.1));
    opacity: 0.3;
    will-change: transform;
}

/* ================================
   Sparkles Background
   ================================ */
.sparkles-container {
    position: absolute;
    width: 100%;
    height: 100%;
}

.sparkle {
    position: absolute;
    width: 4px;
    height: 4px;
    background: white;
    border-radius: 50%;
    box-shadow: 0 0 10px rgba(255, 255, 255, 0.8);
    animation: sparkle 3s ease-in-out infinite;
}

@keyframes sparkle {
    0%, 100% { opacity: 0; transform: scale(1); }
    50% { opacity: 1; }
}

/* ================================
   Clouds
   ================================ */
.clouds {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 200px;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1200 100"><defs><filter id="blur"><feGaussianBlur in="SourceGraphic" stdDeviation="3"/></filter></defs><path d="M150,80 Q130,60 110,80 L130,100 Q150,100 170,100 L190,80 Q170,60 150,80" fill="rgba(255,255,255,0.1)" filter="url(%23blur)"/><path d="M400,85 Q380,65 360,85 L380,105 Q400,105 420,105 L440,85 Q420,65 400,85" fill="rgba(255,255,255,0.08)" filter="url(%23blur)"/><path d="M700,80 Q680,60 660,80 L680,100 Q700,100 720,100 L740,80 Q720,60 700,80" fill="rgba(255,255,255,0.12)" filter="url(%23blur)"/><path d="M950,85 Q930,65 910,85 L930,105 Q950,105 970,105 L990,85 Q970,65 950,85" fill="rgba(255,255,255,0.1)" filter="url(%23blur)"/></svg>') repeat-x;
    background-size: 1200px 100px;
    animation: cloudsMove 20s linear infinite;
    opacity: 0.5;
}

@keyframes cloudsMove {
    0% { transform: translateX(0); }
    100% { transform: translateX(1200px); }
}

/* ================================
   Page Wrapper
   ================================ */
.page-wrapper {
    position: relative;
    z-index: 1;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ================================
   Container
   ================================ */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    z-index: 2;
    position: relative;
}

/* ================================
   Header
   ================================ */
.header {
    background: var(--white-glass);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 15px 0;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 20px;
}

.logo {
    font-size: 24px;
    font-weight: 700;
    background: var(--gradient-blue-pink);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-icon {
    font-size: 28px;
}

.header-nav {
    display: flex;
    gap: 15px;
    align-items: center;
}

.admin-btn {
    background: linear-gradient(135deg, var(--purple-dark), var(--pink-dark));
    color: white;
    border: none;
    padding: 8px 20px;
    border-radius: var(--radius-small);
    font-weight: 600;
    font-size: 14px;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    display: inline-block;
}

.admin-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(139, 92, 246, 0.3);
}

/* ================================
   Buttons
   ================================ */
.btn {
    padding: 14px 32px;
    border: none;
    border-radius: var(--radius-large);
    font-weight: 600;
    font-size: 16px;
    cursor: pointer;
    transition: all var(--transition-normal);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-family: 'Nunito', 'Fredoka', sans-serif;
}

.btn-primary {
    background: linear-gradient(135deg, var(--blue-dark), var(--purple-dark));
    color: white;
    box-shadow: var(--shadow-soft);
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-4px);
    box-shadow: 0 20px 40px rgba(139, 92, 246, 0.3);
}

.btn-primary:active:not(:disabled) {
    transform: translateY(-2px);
}

.btn-secondary {
    background: var(--white-glass-strong);
    color: var(--text-dark);
    border: 2px solid rgba(255, 255, 255, 0.5);
    box-shadow: var(--shadow-soft);
}

.btn-secondary:hover:not(:disabled) {
    background: white;
    box-shadow: var(--shadow-medium);
}

.btn-success {
    background: linear-gradient(135deg, var(--mint-green), var(--blue-pastel));
    color: white;
    box-shadow: var(--shadow-soft);
}

.btn-success:hover:not(:disabled) {
    transform: translateY(-4px);
    box-shadow: 0 20px 40px rgba(134, 239, 172, 0.3);
}

.btn-danger {
    background: linear-gradient(135deg, var(--pink-dark), var(--orange-warm));
    color: white;
    box-shadow: var(--shadow-soft);
}

.btn-danger:hover:not(:disabled) {
    transform: translateY(-4px);
    box-shadow: 0 20px 40px rgba(236, 72, 153, 0.3);
}

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

.btn-small {
    padding: 10px 20px;
    font-size: 14px;
    border-radius: var(--radius-medium);
}

.btn-large {
    padding: 18px 40px;
    font-size: 18px;
    border-radius: var(--radius-xl);
}

/* Pulse animation for buttons */
@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.btn-pulse {
    animation: pulse 2s ease-in-out infinite;
}

/* ================================
   Cards
   ================================ */
.card {
    background: var(--white-glass);
    backdrop-filter: blur(15px);
    border: 1px solid rgba(255, 255, 255, 0.4);
    border-radius: var(--radius-large);
    padding: 30px;
    box-shadow: var(--shadow-soft);
    transition: all var(--transition-normal);
}

.card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-medium);
    border-color: rgba(255, 255, 255, 0.6);
}

.card-small {
    padding: 20px;
    border-radius: var(--radius-medium);
}

/* ================================
   Badges
   ================================ */
.badge {
    display: inline-block;
    padding: 6px 12px;
    border-radius: var(--radius-small);
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.badge-easy {
    background: rgba(134, 239, 172, 0.2);
    color: var(--text-dark);
    border: 1px solid var(--mint-green);
}

.badge-medium {
    background: rgba(253, 230, 138, 0.2);
    color: var(--text-dark);
    border: 1px solid var(--yellow-cream);
}

.badge-hard {
    background: rgba(252, 165, 165, 0.2);
    color: var(--text-dark);
    border: 1px solid var(--red-light);
}

.badge-correct {
    background: rgba(134, 239, 172, 0.3);
    color: var(--text-dark);
}

.badge-wrong {
    background: rgba(252, 165, 165, 0.3);
    color: var(--text-dark);
}

/* ================================
   Input Fields
   ================================ */
.input-field {
    width: 100%;
    padding: 14px 18px;
    border: 2px solid rgba(255, 255, 255, 0.4);
    border-radius: var(--radius-medium);
    font-size: 16px;
    font-family: 'Nunito', 'Fredoka', sans-serif;
    background: var(--white-glass-strong);
    color: var(--text-dark);
    transition: all var(--transition-fast);
    backdrop-filter: blur(10px);
}

.input-field:focus {
    outline: none;
    border-color: var(--blue-dark);
    box-shadow: 0 0 20px rgba(14, 165, 233, 0.3);
    transform: scale(1.02);
}

.input-field::placeholder {
    color: rgba(31, 41, 55, 0.5);
}

textarea.input-field {
    resize: vertical;
    min-height: 120px;
    font-family: 'Courier New', monospace;
}

/* ================================
   Text Utilities
   ================================ */
.text-center {
    text-align: center;
}

.text-large {
    font-size: 28px;
    font-weight: 700;
}

.text-huge {
    font-size: 56px;
    font-weight: 800;
}

.text-gradient {
    background: var(--gradient-blue-pink);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ================================
   Flexbox Utilities
   ================================ */
.flex {
    display: flex;
}

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

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

.flex-column {
    display: flex;
    flex-direction: column;
}

.gap-10 { gap: 10px; }
.gap-15 { gap: 15px; }
.gap-20 { gap: 20px; }
.gap-30 { gap: 30px; }

/* ================================
   Spacing Utilities
   ================================ */
.mt-20 { margin-top: 20px; }
.mt-30 { margin-top: 30px; }
.mt-40 { margin-top: 40px; }

.mb-20 { margin-bottom: 20px; }
.mb-30 { margin-bottom: 30px; }
.mb-40 { margin-bottom: 40px; }

.p-20 { padding: 20px; }
.p-30 { padding: 30px; }
.p-40 { padding: 40px; }

/* ================================
   Grid
   ================================ */
.grid {
    display: grid;
    gap: 30px;
}

.grid-3 {
    grid-template-columns: repeat(3, 1fr);
}

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

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

/* ================================
   Animations
   ================================ */
@keyframes fadeUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes popIn {
    0% {
        opacity: 0;
        transform: scale(0.8);
    }
    50% {
        transform: scale(1.05);
    }
    100% {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

@keyframes glow {
    0%, 100% { filter: drop-shadow(0 0 5px rgba(255, 255, 255, 0.3)); }
    50% { filter: drop-shadow(0 0 15px rgba(126, 211, 252, 0.6)); }
}

.animate-fadeup {
    animation: fadeUp 0.6s ease-out;
}

.animate-fadein {
    animation: fadeIn 0.4s ease-out;
}

.animate-popIn {
    animation: popIn 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* ================================
   Responsive Design
   ================================ */
@media (max-width: 1024px) {
    .grid-3 { grid-template-columns: repeat(2, 1fr); }
    
    .container {
        max-width: 900px;
    }
}

@media (max-width: 768px) {
    :root {
        --radius-large: 24px;
        --radius-xl: 32px;
    }
    
    .grid-3, .grid-2 { grid-template-columns: 1fr; }
    
    .header-content {
        padding: 10px;
    }
    
    .logo {
        font-size: 20px;
    }
    
    .text-large {
        font-size: 24px;
    }
    
    .text-huge {
        font-size: 36px;
    }
    
    .btn {
        padding: 12px 24px;
        font-size: 14px;
    }
    
    .card {
        padding: 20px;
    }
    
    .container {
        max-width: 100%;
        padding: 0 16px;
    }
}

@media (max-width: 480px) {
    .header-nav {
        gap: 10px;
    }
    
    .admin-btn {
        padding: 6px 12px;
        font-size: 12px;
    }
    
    .text-huge {
        font-size: 28px;
    }
    
    .text-large {
        font-size: 20px;
    }
    
    .btn {
        width: 100%;
        padding: 14px 20px;
    }
}

/* ================================
   Scrollbar Styling
   ================================ */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: rgba(255, 255, 255, 0.1);
}

::-webkit-scrollbar-thumb {
    background: rgba(125, 211, 252, 0.5);
    border-radius: 10px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(125, 211, 252, 0.8);
}