/* Premium Minimalist Design (Dark Mode by Default) */
:root {
    --bg-color: #0f172a;
    --text-color: #f8fafc;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --card-bg: rgba(30, 41, 59, 0.7);
    --border-color: rgba(255, 255, 255, 0.1);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    padding: 2rem 1rem;
    background-image: radial-gradient(circle at 50% 0%, #1e293b 0%, #0f172a 70%);
}

header {
    text-align: center;
    margin-bottom: 3rem;
    max-width: 600px;
}

h1 {
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -0.025em;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, #60a5fa, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

h1 span {
    display: block;
    font-size: 1.25rem;
    font-weight: 400;
    color: #94a3b8;
    margin-top: 0.5rem;
    -webkit-text-fill-color: #94a3b8;
}

main {
    width: 100%;
    max-width: 700px;
}

#wall {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.input-group {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    backdrop-filter: blur(10px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

textarea {
    width: 100%;
    min-height: 100px;
    background: rgba(15, 23, 42, 0.5);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1rem;
    color: var(--text-color);
    font-size: 1rem;
    font-family: inherit;
    resize: vertical;
    transition: border-color 0.2s, box-shadow 0.2s;
    margin-bottom: 1rem;
}

textarea:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.25);
}

button {
    background-color: var(--accent-color);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
    width: 100%;
}

button:hover {
    background-color: var(--accent-hover);
}

button:active {
    transform: scale(0.98);
}

button:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

#messageWall {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-top: 1rem;
}

.message-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.25rem;
    backdrop-filter: blur(10px);
    animation: fadeIn 0.4s ease-out;
}

.message-card p {
    font-size: 1.05rem;
    margin-bottom: 0.5rem;
    word-break: break-word;
}

.timestamp {
    font-size: 0.75rem;
    color: #64748b;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

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