/* ==========================================================================
   1. CSS VARIABLES & SYSTEM RESET
   ========================================================================== */
:root {
    --bg-main: #0B0F19;
    --bg-surface: #161D30;
    --bg-surface-elevated: #222C47;
    
    --color-text-primary: #F3F4F6;
    --color-text-secondary: #9CA3AF;
    --color-text-muted: #6B7280;
    
    --accent-primary: #10B981; /* Secure Emerald Green */
    --accent-hover: #059669;
    --accent-danger: #EF4444;
    
    --border-color: #2D3748;
    --max-width: 1100px;
    --transition-smooth: all 0.2s ease-in-out;
}

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

html {
    scroll-behavior: smooth;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-main);
    color: var(--color-text-primary);
    line-height: 1.6;
}

/* Accessibility: Skip to Content */
.skip-link {
    position: absolute;
    top: -100px;
    left: 20px;
    background: var(--accent-primary);
    color: var(--bg-main);
    padding: 10px 20px;
    font-weight: bold;
    z-index: 999;
    transition: top 0.2s;
}
.skip-link:focus {
    top: 20px;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

/* ==========================================================================
   2. REUSABLE UTILITIES & LAYOUT
   ========================================================================== */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 28px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: var(--transition-smooth);
    width: 100%;
}

.btn-primary {
    background-color: var(--accent-primary);
    color: var(--bg-main);
}
.btn-primary:hover, .btn-primary:focus {
    background-color: var(--accent-hover);
    outline: 2px solid var(--color-text-primary);
}

.btn-secondary {
    background-color: var(--bg-surface-elevated);
    color: var(--color-text-primary);
    border: 1px solid var(--border-color);
}
.btn-secondary:hover, .btn-secondary:focus {
    background-color: var(--border-color);
    border-color: var(--color-text-secondary);
}

/* ==========================================================================
   3. HEADER / NAVIGATION
   ========================================================================== */
.app-header {
    background-color: rgba(11, 15, 25, 0.8);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    height: 70px;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: -0.025em;
}

.logo-icon {
    font-size: 1.4rem;
}

.app-nav {
    display: flex;
    align-items: center;
    gap: 24px;
}

.app-nav a {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: var(--transition-smooth);
}

.app-nav a:hover, .app-nav a:focus {
    color: var(--color-text-primary);
}

.app-nav .nav-github {
    border: 1px solid var(--border-color);
    padding: 6px 14px;
    border-radius: 6px;
    background-color: var(--bg-surface);
}

/* ==========================================================================
   4. HERO SECTION & ACTION CARD
   ========================================================================== */
.hero-section {
    padding: 80px 0 60px;
    text-align: center;
}

.hero-title {
    font-size: clamp(2rem, 5vw, 3.5rem);
    line-height: 1.15;
    font-weight: 800;
    max-width: 800px;
    margin: 0 auto 24px;
    letter-spacing: -0.03em;
}

.hero-subtitle {
    font-size: clamp(1.1rem, 2vw, 1.25rem);
    color: var(--color-text-secondary);
    max-width: 650px;
    margin: 0 auto 48px;
}

/* Action Dashboard Card */
.action-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 40px;
    max-width: 760px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr;
    gap: 32px;
    text-align: left;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

.action-group h2 {
    font-size: 1.25rem;
    margin-bottom: 6px;
}

.action-group p {
    color: var(--color-text-secondary);
    font-size: 0.95rem;
    margin-bottom: 20px;
}

.divider {
    display: flex;
    align-items: center;
    text-align: center;
    color: var(--color-text-muted);
    font-size: 0.85rem;
    font-weight: 700;
}

.divider::before, .divider::after {
    content: '';
    flex: 1;
    border-bottom: 1px solid var(--border-color);
}

.divider span {
    padding: 0 16px;
}

.join-form {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.join-form input {
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    color: var(--color-text-primary);
    padding: 14px 18px;
    font-size: 1rem;
    border-radius: 8px;
    outline: none;
    transition: var(--transition-smooth);
    width: 100%;
}

.join-form input:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px rgba(16, 185, 129, 0.2);
}

/* ==========================================================================
   5. FEATURES MATRIX
   ========================================================================== */
.features-section, .security-section {
    padding: 80px 0;
    border-top: 1px solid var(--border-color);
}

.section-title {
    font-size: 2rem;
    text-align: center;
    margin-bottom: 48px;
    letter-spacing: -0.02em;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 24px;
}

.feature-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    padding: 32px;
    border-radius: 12px;
    transition: transform 0.2s ease;
}

.feature-card:hover {
    transform: translateY(-4px);
}

.feature-icon {
    font-size: 2rem;
    margin-bottom: 16px;
}

.feature-card h3 {
    font-size: 1.15rem;
    margin-bottom: 10px;
}

.feature-card p {
    color: var(--color-text-secondary);
    font-size: 0.95rem;
    line-height: 1.5;
}

/* ==========================================================================
   6. PRIVACY TRUST TABLE
   ========================================================================== */
.section-subtitle {
    text-align: center;
    color: var(--color-text-secondary);
    margin-top: -36px;
    margin-bottom: 48px;
}

.table-wrapper {
    overflow-x: auto;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background-color: var(--bg-surface);
}

table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
    font-size: 0.95rem;
    min-width: 600px;
}

th, td {
    padding: 18px 24px;
    border-bottom: 1px solid var(--border-color);
}

thead th {
    background-color: var(--bg-surface-elevated);
    color: var(--color-text-primary);
    font-weight: 600;
}

tbody th {
    font-weight: 500;
    color: var(--color-text-primary);
}

tbody tr:last-child th, tbody tr:last-child td {
    border-bottom: none;
}

.status-yes {
    color: var(--accent-primary);
    font-weight: 600;
}

.status-no {
    color: var(--accent-danger);
    font-weight: 600;
}

/* ==========================================================================
   7. FOOTER
   ========================================================================== */
.app-footer {
    border-top: 1px solid var(--border-color);
    padding: 40px 0;
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

.footer-container {
    display: flex;
    flex-direction: column;
    gap: 16px;
    text-align: center;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
}

.footer-links a {
    color: var(--color-text-secondary);
    text-decoration: none;
    transition: var(--transition-smooth);
}

.footer-links a:hover {
    color: var(--color-text-primary);
}

/* ==========================================================================
   8. MEDIA QUERIES (DESKTOP OPTIMIZATIONS)
   ========================================================================== */
@media (min-width: 768px) {
    .action-card {
        grid-template-columns: 1fr 50px 1fr;
        align-items: center;
    }
    
    .divider {
        flex-direction: column;
        height: 100%;
    }
    
    .divider::before, .divider::after {
        border-bottom: none;
        border-left: 1px solid var(--border-color);
    }
    
    .divider span {
        padding: 12px 0;
    }
    
    .join-form {
        flex-direction: row;
        gap: 8px;
    }
    
    .join-form .btn {
        width: auto;
        white-space: nowrap;
    }
    
    .footer-container {
        flex-direction: row;
        justify-content: space-between;
        text-align: left;
    }
}




/* ==========================================================================
   1. CHAT ROOM SYSTEM LAYOUT
   ========================================================================== */
.room-body {
    background-color: var(--bg-main);
    display: flex;
    flex-direction: column;
    height: 100vh; /* Lock viewport height */
    overflow: hidden;
}

.room-layout {
    display: grid;
    grid-template-columns: 1fr;
    flex: 1;
    height: calc(100vh - 70px); /* Subtract Header height */
    overflow: hidden;
    padding-top: 20px;
    padding-bottom: 20px;
    gap: 20px;
}

@media (min-width: 900px) {
    .room-layout {
        grid-template-columns: 320px 1fr; /* Lock sidebar width on desktop */
    }
    
}

/* ==========================================================================
   2. SIDEBAR PANEL & SESSION STATS
   ========================================================================== */
.room-sidebar {
    display: flex;
    flex-direction: column;
    gap: 16px;
    overflow-y: auto;
    max-height: 100%;
}

@media (max-width: 899px) {
    .room-sidebar {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
        max-height: 250px; /* Restrict screen real estate on small windows */
        border-bottom: 1px solid var(--border-color);
        padding-bottom: 16px;
    }
    .room-sidebar{
        display: none;
    }
}

.sidebar-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 20px;
}

.sidebar-card h3 {
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-primary);
    margin-bottom: 8px;
}

.sidebar-meta {
    font-size: 0.8rem;
    color: var(--color-text-secondary);
    margin-bottom: 12px;
    line-height: 1.4;
}

/* Share Input Controls */
.share-input-group {
    display: flex;
    gap: 6px;
}

.share-input-group input {
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    color: var(--color-text-secondary);
    padding: 10px 12px;
    font-size: 0.85rem;
    border-radius: 6px;
    width: 100%;
    outline: none;
    font-family: monospace;
}

.btn-icon {
    background-color: var(--bg-surface-elevated);
    border: 1px solid var(--border-color);
    color: var(--color-text-primary);
    padding: 0 12px;
    border-radius: 6px;
    cursor: pointer;
    transition: var(--transition-smooth);
}
.btn-icon:hover {
    background-color: var(--border-color);
}

/* Fingerprint (SAS) Display */
.sas-display {
    background-color: var(--bg-main);
    border: 1px dashed var(--border-color);
    padding: 12px;
    border-radius: 6px;
    text-align: center;
    font-family: monospace;
    font-weight: 700;
    font-size: 1.15rem;
    letter-spacing: 0.1em;
    color: var(--accent-primary);
}

.sas-placeholder {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    font-style: italic;
    letter-spacing: normal;
}

/* Presence Roster */
.peer-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.peer-item {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.9rem;
}

.status-indicator {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: var(--color-text-muted);
}
.status-indicator.online {
    background-color: var(--accent-primary);
}

.peer-name {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* ==========================================================================
   3. CHAT VIEWPORT & MESSAGES STREAM
   ========================================================================== */
.chat-panel {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    height: 100%;
}

/* Global Dynamic State Badges */
.badge {
    font-size: 0.75rem;
    padding: 4px 10px;
    border-radius: 20px;
    font-weight: 600;
}
.badge-secure {
    background-color: rgba(16, 185, 129, 0.15);
    color: var(--accent-primary);
    border: 1px solid rgba(16, 185, 129, 0.3);
}

/* Security Notification Banners */
.security-banner {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 14px 20px;
    font-size: 0.85rem;
    border-bottom: 1px solid var(--border-color);
}
.banner-warning {
    background-color: rgba(239, 68, 68, 0.08);
    color: #FCA5A5;
}
.banner-verified {
    background-color: rgba(16, 185, 129, 0.08);
    color: #A7F3D0;
}

/* Scrollable Message Box */
.message-viewport {
    flex: 1;
    overflow-y: auto;
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

/* System Message Styles */
.system-message {
    align-self: center;
    background-color: var(--bg-surface-elevated);
    border: 1px solid var(--border-color);
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 0.8rem;
    color: var(--color-text-secondary);
    text-align: center;
}

/* Chat Message Bubbles */
.chat-message {
    display: flex;
    flex-direction: column;
    max-width: 75%;
}

.message-incoming {
    align-self: flex-start;
}

.message-outgoing {
    align-self: flex-end;
}

.msg-meta {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    margin-bottom: 4px;
    padding: 0 4px;
}
.message-outgoing .msg-meta {
    align-self: flex-end;
}

.msg-bubble {
    padding: 12px 18px;
    border-radius: 14px;
    font-size: 0.95rem;
    word-break: break-word;
}

.message-incoming .msg-bubble {
    background-color: var(--bg-surface-elevated);
    color: var(--color-text-primary);
    border-bottom-left-radius: 4px;
}

.message-outgoing .msg-bubble {
    background-color: var(--accent-primary);
    color: var(--bg-main);
    font-weight: 500;
    border-bottom-right-radius: 4px;
}

/* ==========================================================================
   4. COMPOSER COMPONENT (INPUT CONTROL AREA)
   ========================================================================== */
.chat-input-area {
    padding: 20px;
    border-top: 1px solid var(--border-color);
    background-color: var(--bg-surface);
}

.message-form {
    display: flex;
    align-items: flex-end;
    gap: 12px;
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 8px 12px;
}
.message-form:focus-within {
    border-color: var(--accent-primary);
}

.input-wrapper {
    flex: 1;
}

.message-form textarea {
    width: 100%;
    background: transparent;
    border: none;
    outline: none;
    color: var(--color-text-primary);
    font-size: 0.95rem;
    padding: 8px 4px;
    resize: none;
    max-height: 120px;
    font-family: inherit;
    line-height: 1.4;
}

.btn-send {
    background-color: var(--accent-primary);
    color: var(--bg-main);
    border: none;
    border-radius: 8px;
    width: 38px;
    height: 38px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-smooth);
    flex-shrink: 0;
}
.btn-send:hover:not(:disabled) {
    background-color: var(--accent-hover);
}
.btn-send:disabled {
    background-color: var(--bg-surface-elevated);
    color: var(--color-text-muted);
    cursor: not-allowed;
}

.input-meta-hint {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    text-align: center;
    margin-top: 10px;
}

/* Header Override for App Disconnect Actions */
.btn-disconnect {
    background-color: transparent;
    border: 1px solid var(--accent-danger);
    color: var(--accent-danger);
    padding: 8px 16px;
    font-size: 0.85rem;
    font-weight: 600;
    border-radius: 6px;
    cursor: pointer;
    transition: var(--transition-smooth);
}
.btn-disconnect:hover {
    background-color: var(--accent-danger);
    color: var(--color-text-primary);
}