:root {
    --font-sans: Inter, system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial;
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --danger-color: #ef4444;
    --danger-hover: #dc2626;
    --success-color: #16a34a;
    --success-bg: #dcfce7;
    --error-color: #b91c1c;
    --error-bg: #fee2e2;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --surface-bg: #ffffff;
    --page-bg: #f8fafc;
    --border-color: #e2e8f0;
    --border-focus: #a5b4fc;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -2px rgb(0 0 0 / 0.1);
    --border-radius: 0.75rem;
    --transition: all 0.2s ease-in-out;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body {
    font-family: var(--font-sans);
    background:linear-gradient(180deg,#eef2ff,#f7fbff);
    color: var(--text-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1.25rem;
}
.card {
    width: 100%;
    max-width: 420px;
    background-color: var(--surface-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    transition: max-width 0.4s ease-in-out, height 0.4s ease-in-out;
}
.card.app-expanded { max-width: 1100px; }

.logo {
    width: 60px;
    height: 60px;
    border-radius: 12px;
    background: linear-gradient(135deg,#6ee7b7,#3b82f6);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-weight: 700;
    font-size: 1.4rem;
}
.brand .logo { width: 44px; height: 44px; }

.btn {
    padding: 0.75rem 1rem;
    border: none;
    border-radius: 0.5rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.95rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    text-decoration: none;
}
.btn:hover { transform: translateY(-2px); box-shadow: var(--shadow); }
.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
}
.btn-primary:hover { background-color: var(--primary-hover); }
.btn-secondary {
    background-color: #f1f5f9;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}
.btn-secondary:hover { background-color: #e2e8f0; }
.btn-danger {
    background-color: var(--danger-color);
    color: white;
}
.btn-danger:hover { background-color: var(--danger-hover); }

.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 0.95rem;
    transition: var(--transition);
}
.form-control:focus {
    outline: none;
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}
.form-switch { margin-top: 1rem; font-size: 0.9rem; }
.form-switch a { color: var(--primary-color); text-decoration: none; font-weight: 600; }
.form-switch a:hover { text-decoration: underline; }

.message {
    padding: 0.75rem 1rem;
    border-radius: 0.5rem;
    font-size: 0.9rem;
    margin-top: 1rem;
}
.message.error { color: var(--error-color); background-color: var(--error-bg); }
.message.success { color: var(--success-color); background-color: var(--success-bg); }

.login-container { padding: 2rem 1.75rem; text-align: center; }
.login-header { margin-bottom: 1.75rem; }
.login-header .logo { margin: 0 auto 1rem; }
.login-header h2 { font-size: 1.5rem; margin-bottom: 0.5rem; color: var(--text-primary); }
.login-header p { color: var(--text-secondary); }
#auth-form { display: flex; flex-direction: column; gap: 0.875rem; }
#submit-btn {
    margin-top: 0.5rem;
    background: linear-gradient(135deg, #6ee7b7, #3b82f6);
    color: #fff;
}
#submit-btn:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3); }

.header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
    gap: 1rem;
}
.header-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-shrink: 0;
}
.greeting-text {
    font-weight: 600;
    color: var(--text-primary);
}
.brand { display: flex; gap: 0.75rem; align-items: center; }
.title { font-size: 1.1rem; font-weight: 700; color: var(--text-primary); }
.muted { color: var(--text-secondary); font-size: 0.9rem; }

.main {
    display: grid;
    gap: 1.25rem;
    padding: 1.5rem;
    grid-template-columns: 320px 1fr;
}
.main.single-panel { grid-template-columns: 1fr; }

.panel {
    background-color: var(--surface-bg);
    border-radius: var(--border-radius);
    padding: 1.25rem;
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}
.panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1rem;
    flex-shrink: 0;
}
.panel-header h3 { margin: 0; font-size: 1.25rem; }
.files-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
}
.files-list-container {
    background-color: var(--page-bg);
    border-radius: 0.5rem;
    overflow: auto;
    flex-grow: 1;
    min-height: 200px;
    max-height: 65vh;
}
#file-list { list-style: none; padding: 0.5rem; }

.sort-dropdown { position: relative; }
.sort-menu {
    display: none;
    position: absolute;
    top: 110%;
    right: 0;
    min-width: 160px;
    background-color: var(--surface-bg);
    border-radius: 0.5rem;
    box-shadow: var(--shadow-lg);
    z-index: 100;
    padding: 0.5rem;
    border: 1px solid var(--border-color);
}
.sort-menu.visible { display: block; }
.sort-menu button {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    width: 100%;
    text-align: left;
    padding: 0.5rem 0.75rem;
    cursor: pointer;
    background: none;
    border: none;
    border-radius: 0.25rem;
    font-weight: 500;
}
.sort-menu button:hover { background-color: var(--page-bg); }
.sort-menu button.active {
    background-color: var(--primary-color);
    color: #fff;
}

.drop-cover {
    border: 2px dashed var(--border-color);
    border-radius: 0.5rem;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    align-items: center;
    justify-content: center;
    min-height: 160px;
    transition: var(--transition);
    text-align: center;
}
.drop-cover:hover { border-color: var(--primary-color); background-color: #f0f9ff; }
#select-file-btn { background: linear-gradient(135deg, #6ee7b7, #3b82f6); }

.file-row {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.75rem;
    border-radius: 0.5rem;
    background-color: var(--surface-bg);
    margin-bottom: 0.5rem;
    box-shadow: 0 1px 2px rgba(0,0,0,0.05);
    transition: var(--transition);
}
.file-row:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
    background-color: #f8fafc;
}
.file-icon {
    flex-shrink: 0;
    width: 40px;
    height: 40px;
    font-size: 2rem;
    display: flex;
    align-items: center;
    justify-content: center;
}
.file-meta { 
    flex: 1;
    min-width: 0;
}
.file-name {
    display: inline-block;
    max-width: 20vw;
    overflow: hidden;
    font-weight: 600;
    text-overflow: ellipsis;
    white-space: nowrap;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow:
    ellipsis;
    margin-bottom: 0.35rem;
}
.file-sub {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    font-size: 0.8rem;
    color: var(--text-secondary);
}
.meta-item {
    display: flex; align-items: center; gap: 0.35rem;
}
.meta-item .fa-solid {
    font-size: 0.7rem;
}
.menu-trigger {
    background-color: transparent;
    border: none;
    font-size: 1.25rem;
    cursor: pointer;
    border-radius: 50%;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
}
.menu-trigger:hover { background-color: #e2e8f0; color: var(--text-primary); }

#floating-menu {
    position: fixed;
    display: none;
    min-width: 150px;
    border-radius: 0.5rem;
    background-color: var(--surface-bg);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    overflow: hidden;
    padding: 0.25rem;
}
#floating-menu button {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    width: 100%;
    padding: 0.5rem 0.75rem;
    border: 0;
    background: none;
    text-align: left;
    cursor: pointer;
    border-radius: 0.25rem;
}
#floating-menu button:hover { background-color: var(--page-bg); }

.modal-overlay {
    position: fixed;
    inset: 0;
    display: none;
    align-items: center;
    justify-content: center;
    background: rgba(15, 23, 42, 0.6);
    z-index: 3000;
    backdrop-filter: blur(2px);
}
.modal-content {
    background-color: var(--surface-bg);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    max-width: 400px;
    width: 90%;
    box-shadow: var(--shadow-lg);
    text-align: center;
}
.modal-content h3 { font-size: 1.2rem; margin-bottom: 0.75rem; color: var(--text-primary); }
.modal-content p { font-size: 0.95rem; color: var(--text-secondary); margin-bottom: 1.5rem; }
.modal-actions { display: flex; gap: 0.75rem; justify-content: center; }

#global-drop-overlay {
    position: fixed;
    inset: 0;
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    background: rgba(248, 250, 252, 0.7);
    backdrop-filter: blur(4px);
    transition: opacity 0.3s;
}
.overlay-card {
    padding: 3rem 4rem;
    border-radius: var(--border-radius);
    border: 2px dashed var(--primary-color);
    background-color: rgba(255, 255, 255, 0.8);
    text-align: center;
    animation: pulse 2s infinite;
}
.overlay-icon {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}
.overlay-text {
    font-weight: 600;
    font-size: 1.2rem;
    color: var(--text-primary);
}
@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.03); }
    100% { transform: scale(1); }
}

#toast-container {
    position: fixed;
    top: 1.5rem;
    right: 1.5rem;
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}
.toast {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 1.25rem;
    background-color: var(--surface-bg);
    color: var(--text-primary);
    border-radius: 0.5rem;
    box-shadow: var(--shadow-lg);
    transform: translateX(120%);
    transition: transform 0.5s ease-in-out;
    border-left: 4px solid;
}
.toast.visible { transform: translateX(0); }
.toast-info { border-color: var(--primary-color); }
.toast-success { border-color: var(--success-color); }
.toast-error { border-color: var(--danger-color); }
.toast .fa-solid { font-size: 1.25rem; }
.toast-info .fa-solid { color: var(--primary-color); }
.toast-success .fa-solid { color: var(--success-color); }
.toast-error .fa-solid { color: var(--danger-color); }

@media (max-width: 860px) {
    .main { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
    .page { padding: 0; align-items: flex-start; }
    .card { max-width: 100%; min-height: 100vh; border-radius: 0; box-shadow: none; }
    .login-container { padding-top: 5rem; }
    
    .header {
        flex-wrap: wrap;
    }
    .brand {
        width: 100%;
        margin-bottom: 0.5rem;
    }
    .header-actions {
        width: 100%;
        justify-content: space-between;
    }

    .main { padding: 1rem; }
    .panel { padding: 1rem; }
    .file-row { flex-direction: column; align-items: flex-start; gap: 0.5rem; }
    .file-actions { align-self: flex-end; }
}