* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
    --bg-primary: #f8fafc;
    --bg-secondary: #f1f5f9;
    --bg-panel: rgba(255, 255, 255, 0.85);
    --accent-1: #3b82f6;
    --accent-2: #8b5cf6;
    --accent-3: #10b981;
    --accent-danger: #ef4444;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --glass-border: rgba(0, 0, 0, 0.08);
    --glass-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.07);
}

body {
    font-family: 'Inter', 'Noto Sans Bengali', sans-serif;
    background-color: var(--bg-primary);
    background-image: 
        radial-gradient(circle at 15% 50%, rgba(139, 92, 246, 0.08) 0%, transparent 50%),
        radial-gradient(circle at 85% 30%, rgba(59, 130, 246, 0.08) 0%, transparent 50%);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 2rem;
    overflow-x: hidden;
}

body::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: 
        linear-gradient(rgba(0,0,0,0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0,0,0,0.03) 1px, transparent 1px);
    background-size: 30px 30px;
    z-index: -1;
    pointer-events: none;
    mask-image: radial-gradient(circle at center, black 40%, transparent 80%);
    -webkit-mask-image: radial-gradient(circle at center, black 40%, transparent 80%);
}

.app-container {
    width: 100%;
    max-width: 1400px;
    background: var(--bg-panel);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: 24px;
    padding: 2.5rem 3rem;
    box-shadow: var(--glass-shadow);
    position: relative;
    overflow: hidden;
}

.app-container::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; height: 4px;
    background: linear-gradient(90deg, transparent, var(--accent-1), var(--accent-2), transparent);
    z-index: 10;
}

.app-header {
    text-align: center;
    margin-bottom: 2.5rem;
    position: relative;
}

.logo {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 1rem;
    padding: 10px 24px;
    background: rgba(255, 255, 255, 0.5);
    border-radius: 100px;
    border: 1px solid var(--glass-border);
    box-shadow: 0 4px 15px rgba(0,0,0,0.02);
}

.logo svg {
    color: var(--accent-1);
    animation: pulse 2s infinite alternate;
}

@keyframes pulse {
    0% { transform: scale(0.95); }
    100% { transform: scale(1.05); }
}

h1 {
    font-size: 2.4rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--accent-1) 0%, var(--accent-2) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -0.5px;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.15rem;
    max-width: 600px;
    margin: 0 auto;
}

.converter-layout {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 2rem;
    align-items: stretch;
}

.panel {
    background: rgba(255, 255, 255, 0.7);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    transition: all 0.3s ease;
    position: relative;
    box-shadow: 0 4px 20px rgba(0,0,0,0.02);
}

.panel:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 35px -10px rgba(59, 130, 246, 0.15);
    border-color: rgba(59, 130, 246, 0.25);
}

.panel.highlight {
    animation: glow-pulse 1.5s ease-out;
}

@keyframes glow-pulse {
    0% { box-shadow: 0 0 0 0 rgba(59, 130, 246, 0.3); border-color: var(--accent-1); }
    70% { box-shadow: 0 0 0 15px rgba(59, 130, 246, 0); }
    100% { box-shadow: 0 0 0 0 rgba(59, 130, 246, 0); }
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid rgba(0,0,0,0.06);
}

.panel-header h2 {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 10px;
}

.panel-header h2::before {
    content: '';
    display: block;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--accent-1);
}

.actions {
    display: flex;
    gap: 0.5rem;
}

.btn {
    border: none;
    border-radius: 12px;
    cursor: pointer;
    font-family: inherit;
    font-weight: 600;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0; left: -100%; width: 100%; height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    transition: left 0.5s ease;
}

.btn:hover::before {
    left: 100%;
}

.btn:active {
    transform: scale(0.96);
}

.btn-primary, .btn-secondary {
    padding: 14px 28px;
    font-size: 1.1rem;
    width: 100%;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-1) 0%, var(--accent-2) 100%);
    color: white;
}
.btn-primary:hover {
    box-shadow: 0 6px 20px rgba(59, 130, 246, 0.35);
}

.btn-secondary {
    background: linear-gradient(135deg, #0ea5e9 0%, #0284c7 100%);
    color: white;
}
.btn-secondary:hover {
    box-shadow: 0 6px 20px rgba(14, 165, 233, 0.35);
}

.btn-danger {
    background: rgba(239, 68, 68, 0.08);
    color: var(--accent-danger);
    border: 1px solid rgba(239, 68, 68, 0.25);
}
.btn-danger:hover {
    background: rgba(239, 68, 68, 0.15);
}

.btn-success {
    background: rgba(16, 185, 129, 0.08);
    color: var(--accent-3);
    border: 1px solid rgba(16, 185, 129, 0.25);
}
.btn-success:hover {
    background: rgba(16, 185, 129, 0.15);
}

.btn-icon {
    background: rgba(0, 0, 0, 0.03);
    color: var(--text-secondary);
    padding: 10px;
    border: 1px solid transparent;
    border-radius: 10px;
}
.btn-icon:hover {
    background: rgba(0, 0, 0, 0.08);
    color: var(--text-primary);
}

.conversion-controls {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 1.5rem;
    padding: 1.5rem 0;
}

.custom-textarea {
    width: 100%;
    min-height: 480px;
    height: 55vh;
    background: transparent;
    border: none;
    resize: none;
    color: var(--text-primary);
    line-height: 1.7;
    outline: none;
    padding: 0.5rem;
}

.custom-textarea::placeholder {
    color: rgba(71, 85, 105, 0.5);
}

.custom-textarea::-webkit-scrollbar { width: 8px; }
.custom-textarea::-webkit-scrollbar-track { background: rgba(0,0,0,0.03); border-radius: 10px; }
.custom-textarea::-webkit-scrollbar-thumb { background: rgba(0,0,0,0.15); border-radius: 10px; }
.custom-textarea::-webkit-scrollbar-thumb:hover { background: var(--accent-1); }

@font-face {
    font-family: 'SutonnyMJ';
    src: url('SutonnyMJ.ttf') format('truetype');
    font-weight: normal;
    font-style: normal;
}

.font-unicode { font-family: 'Noto Sans Bengali', sans-serif; font-size: 1.25rem; }
.font-bijoy { font-family: 'SutonnyMJ', Arial, sans-serif !important; font-size: 1.8rem !important; letter-spacing: 0.5px; }

.app-footer {
    text-align: center;
    margin-top: 3.5rem;
    color: var(--text-secondary);
    font-size: 0.95rem;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 6px;
}

.toast-container {
    position: fixed;
    top: 30px;
    right: 30px;
    transform: translateX(120%);
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(12px);
    color: var(--text-primary);
    padding: 14px 28px;
    border-radius: 14px;
    border: 1px solid var(--glass-border);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.15);
    font-weight: 600;
    font-size: 1rem;
    opacity: 0;
    transition: all 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 1000;
    display: flex;
    align-items: center;
    gap: 12px;
}
.toast-container.show {
    transform: translateX(0);
    opacity: 1;
}
.toast-container::before {
    content: ''; display: block; width: 10px; height: 10px; border-radius: 50%; background: var(--accent-1);
}

/* 📱 MOBILE RESPONSIVENESS (Top Tier Experience) */
/* 📱 FLUID & RESPONSIVE DESIGN (Top Tier Experience) */
h1 {
    font-size: clamp(1.8rem, 4vw, 2.4rem);
}
.subtitle {
    font-size: clamp(0.95rem, 2vw, 1.15rem);
    padding: 0 10px;
}
.font-unicode { font-size: clamp(1.1rem, 2vw, 1.25rem); }
.font-bijoy { font-size: clamp(1.3rem, 2.5vw, 1.8rem) !important; }

@media (max-width: 992px) {
    body { padding: 1rem; }
    .app-container { padding: 2rem; border-radius: 20px; }
    .converter-layout { grid-template-columns: 1fr; gap: 1.5rem; }
    .conversion-controls { 
        flex-direction: row; 
        padding: 0; 
        gap: 1rem; 
    }
    .primary-controls {
        flex-direction: row !important;
        width: 100%;
    }
    .secondary-controls {
        flex-direction: column !important;
        margin-top: 0 !important;
        width: auto !important;
    }
    .custom-textarea { min-height: 400px; height: 45vh; }
}

@media (max-width: 768px) {
    body { padding: 0.5rem; background: var(--bg-secondary); }
    .app-container { 
        padding: 1.5rem 1rem; 
        border: none; 
        box-shadow: 0 10px 30px rgba(0,0,0,0.05); 
        background: rgba(255,255,255,0.95); 
        max-width: 100%;
        border-radius: 16px;
    }
    .app-header { margin-bottom: 1.5rem; }
    .panel { padding: 1.25rem 1rem; border-radius: 16px; background: #fff; box-shadow: 0 2px 10px rgba(0,0,0,0.02); }
    
    .conversion-controls { flex-direction: column; gap: 1rem; }
    
    /* Side-by-side buttons on mobile for a compact, app-like feel */
    .primary-controls { 
        display: grid !important; 
        grid-template-columns: 1fr 1fr; 
        gap: 12px; 
    }
    .primary-controls button { padding: 14px 10px; font-size: 1.05rem; border-radius: 12px; }
    
    .secondary-controls { 
        display: grid !important; 
        grid-template-columns: 1fr 1fr; 
        gap: 12px !important; 
    }
    .secondary-controls button { padding: 12px; font-size: 0.95rem; border-radius: 10px; }
    
    .custom-textarea { min-height: 300px; height: 40vh; }
    
    .toast-container {
        top: auto;
        bottom: 20px;
        right: 50%;
        transform: translateX(50%) translateY(100px);
        width: 90%;
        justify-content: center;
        border-radius: 50px;
    }
    .toast-container.show {
        transform: translateX(50%) translateY(0);
    }
}
@media (max-width: 400px) {
    /* For extremely small screens (like iPhone SE) */
    .primary-controls, .secondary-controls { grid-template-columns: 1fr; }
}


/* Enhanced Interactive Micro-styles */
.char-count {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-secondary);
    background: rgba(0, 0, 0, 0.04);
    padding: 3px 10px;
    border-radius: 20px;
    letter-spacing: 0.2px;
}

.copy-btn {
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}
.copy-btn:hover {
    transform: scale(1.08);
}
.copy-btn:active {
    transform: scale(0.92);
}

.convert-btn:hover {
    transform: translateY(-2px);
}
.convert-btn:active {
    transform: translateY(1px);
}