:root {
    --bg-gradient-1: #0f172a;
    --bg-gradient-2: #1e293b;
    --accent-color: #38bdf8;
    --accent-glow: rgba(56, 189, 248, 0.4);
    --glass-bg: rgba(255, 255, 255, 0.03);
    --glass-border: rgba(255, 255, 255, 0.08);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --success: #22c55e;
    --font-family: 'Outfit', sans-serif;
    --transition-speed: 0.3s;
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-gradient-1);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow-x: hidden;
    line-height: 1.6;
}

.background-mesh {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background: 
        radial-gradient(circle at 15% 50%, rgba(56, 189, 248, 0.08), transparent 25%),
        radial-gradient(circle at 85% 30%, rgba(139, 92, 246, 0.08), transparent 25%);
    filter: blur(40px);
}

.container {
    width: 100%;
    max-width: 500px;
    padding: 20px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

header {
    text-align: center;
    margin-bottom: 1rem;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, #fff 0%, var(--accent-color) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -1px;
    margin-bottom: 0.5rem;
}

header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: 24px;
    padding: 2rem;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    transition: transform var(--transition-speed) ease;
}

/* Tabs */
.tabs {
    display: flex;
    background: rgba(0, 0, 0, 0.3);
    padding: 4px;
    border-radius: 12px;
    margin-bottom: 2rem;
    position: relative;
}

.tab-btn {
    flex: 1;
    background: transparent;
    border: none;
    padding: 10px;
    color: var(--text-muted);
    font-family: var(--font-family);
    font-weight: 600;
    cursor: pointer;
    border-radius: 8px;
    transition: all var(--transition-speed);
}

.tab-btn.active {
    background: var(--glass-border);
    color: var(--text-main);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.tab-content {
    display: none;
    animation: fadeIn 0.4s ease;
}

.tab-content.active {
    display: block;
}

/* Inputs */
.input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

label {
    font-size: 0.9rem;
    color: var(--text-muted);
    font-weight: 500;
    margin-left: 4px;
}

textarea {
    width: 100%;
    min-height: 120px;
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 1rem;
    color: var(--text-main);
    font-family: var(--font-family);
    font-size: 1rem;
    resize: vertical;
    transition: all var(--transition-speed);
}

textarea:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 4px rgba(56, 189, 248, 0.1);
}

/* Buttons */
.action-area {
    margin-bottom: 1.5rem;
}

.primary-btn, .secondary-btn {
    width: 100%;
    padding: 1rem;
    border: none;
    border-radius: 12px;
    font-family: var(--font-family);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.2s ease;
}

.primary-btn {
    background: var(--accent-color);
    color: #0f172a;
    box-shadow: 0 0 20px var(--accent-glow);
}

.primary-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px var(--accent-glow);
    filter: brightness(1.1);
}

.secondary-btn {
    background: var(--glass-border);
    color: var(--text-main);
    margin-top: 1rem;
}

.secondary-btn:hover {
    background: rgba(255, 255, 255, 0.15);
}

.icon {
    width: 20px;
    height: 20px;
}

/* Results */
.result-group {
    border-top: 1px solid var(--glass-border);
    padding-top: 1.5rem;
    margin-top: 1rem;
}

.hidden {
    display: none;
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.badge {
    font-size: 0.75rem;
    color: var(--accent-color);
    background: rgba(56, 189, 248, 0.1);
    padding: 2px 8px;
    border-radius: 12px;
}

.result-box {
    background: rgba(0, 0, 0, 0.4);
    border: 1px dashed var(--glass-border);
    border-radius: 12px;
    padding: 1rem;
    min-height: 60px;
    word-break: break-all;
    font-family: monospace;
    color: var(--text-muted);
    font-size: 0.9rem;
    cursor: text;
}

#encoded-output {
    user-select: all;
    /* Visual cue that it's "invisible" content but selectable */
    color: rgba(255, 255, 255, 0.2); 
}

/* Toast */
.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    background: var(--success);
    color: #fff;
    padding: 12px 24px;
    border-radius: 50px;
    font-weight: 600;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
    opacity: 0;
    pointer-events: none;
    transition: all 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

footer {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.8rem;
    opacity: 0.6;
}

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

@media (max-width: 480px) {
    .container {
        padding: 15px;
    }
    
    .glass-panel {
        padding: 1.5rem;
    }
    
    header h1 {
        font-size: 2rem;
    }
}