:root {
    --bg-color: #0d1117;
    --card-bg: rgba(22, 27, 34, 0.7);
    --border-color: rgba(255, 255, 255, 0.1);
    --text-primary: #c9d1d9;
    --text-muted: #8b949e;
    --accent: #58a6ff;
    --accent-hover: #1f6feb;
}

body {
    margin: 0;
    padding: 0;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background: var(--bg-color);
    color: var(--text-primary);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-image: radial-gradient(circle at top right, #1f2430, transparent);
}

#app-container {
    width: 100%;
    max-width: 480px;
    padding: 20px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}
header h2 { margin: 0; }

.glass-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 32px;
    backdrop-filter: blur(10px);
    box-shadow: 0 8px 32px rgba(0,0,0,0.5);
    display: none;
    animation: fadeIn 0.4s ease-out forwards;
}

.glass-card.active {
    display: block;
}

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

input, textarea {
    width: 100%;
    background: rgba(0,0,0,0.3);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 12px 16px;
    border-radius: 8px;
    margin-bottom: 16px;
    box-sizing: border-box;
    font-size: 16px; /* 16px prevents iOS zoom issue */
    transition: border 0.2s;
}

input:focus, textarea:focus {
    outline: none;
    border-color: var(--accent);
}

.btn {
    padding: 12px 24px;
    border-radius: 8px;
    border: none;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.btn.primary {
    background: var(--accent);
    color: #fff;
}
.btn.primary:hover {
    background: var(--accent-hover);
}
.btn.secondary {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
}
.btn.secondary:hover {
    background: rgba(255,255,255,0.05);
}
.btn.text {
    background: transparent;
    color: var(--accent);
    padding: 8px;
}
.btn.text:hover {
    text-decoration: underline;
}
.btn.full-width {
    width: 100%;
}
.auth-options {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.tabs {
    display: flex;
    margin-bottom: 24px;
    border-bottom: 1px solid var(--border-color);
}
.tab {
    flex: 1;
    background: none;
    border: none;
    color: var(--text-muted);
    padding: 12px;
    cursor: pointer;
    font-weight: 500;
    border-bottom: 2px solid transparent;
}
.tab.active {
    color: var(--text-primary);
    border-color: var(--accent);
}

.tab-panel {
    display: none;
}
.tab-panel.active {
    display: block;
}

.result-box {
    margin-top: 16px;
    padding: 16px;
    background: rgba(0,0,0,0.4);
    border-radius: 8px;
    border: 1px solid var(--border-color);
    word-break: break-all;
    font-size: 13px;
    color: #8b949e;
}
.result-box.success { border-color: #2ea043; color: #3fb950; }
.result-box.error { border-color: #f85149; color: #ff7b72; }
.result-box.hidden { display: none; }

/* Mobile Responsiveness */
@media (max-width: 600px) {
    body {
        align-items: flex-start;
        background-image: none;
    }
    
    #app-container {
        padding: 0;
        max-width: 100%;
    }
    
    .glass-card {
        border-radius: 0;
        border: none;
        box-shadow: none;
        min-height: 100vh;
        padding: 24px 20px;
    }
    
    header {
        margin-bottom: 24px;
    }
    
    .btn {
        padding: 14px 24px;
    }
    
    .tab {
        padding: 14px 8px;
        font-size: 15px;
    }
}

/* Attachment Styles */
.hidden-input { display: none; }
.attachment-label {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 12px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px dashed var(--border-color);
    border-radius: 8px;
    margin-bottom: 16px;
    cursor: pointer;
    color: var(--text-muted);
    transition: all 0.2s;
    font-size: 14px;
}
.attachment-label:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
    border-color: var(--accent);
}
.attachment-label.has-file {
    border-color: #2ea043;
    color: #3fb950;
    background: rgba(46, 160, 67, 0.1);
}
.received-attachment {
    margin-top: 16px;
    padding: 12px;
    background: rgba(0,0,0,0.5);
    border-radius: 8px;
    border: 1px solid var(--border-color);
}
.received-attachment img {
    max-width: 100%;
    border-radius: 4px;
    margin-top: 8px;
    display: block;
}
.received-attachment a.download-link {
    color: var(--accent);
    text-decoration: none;
    display: inline-block;
    margin-top: 8px;
    font-size: 14px;
    font-weight: 500;
}
.received-attachment a.download-link:hover {
    text-decoration: underline;
}