:root {
    --font-sans: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --radius: 12px;
    --radius-sm: 8px;
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
    --c-bg: #0f0f1e;
    --c-bg-secondary: #1a1a2e;
    --c-surface: #16213e;
    --c-surface-hover: #1c2b4a;
    --c-border: #2a2a4a;
    --c-text: #e0e0e0;
    --c-text-secondary: #8888aa;
    --c-primary: #5e72e4;
    --c-primary-hover: #4f60d4;
    --c-primary-bg: rgba(94, 114, 228, 0.12);
    --c-danger: #f56565;
    --c-danger-bg: rgba(245, 101, 101, 0.1);
    --c-success: #48bb78;
    --c-warning: #ecc94b;
    --c-shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
    --star-color: 255, 255, 255;
    --star-opacity: 0.6;
    --meteor-color: 255, 255, 255;
}

[data-theme="light"] {
    --c-bg: #f0f2f5;
    --c-bg-secondary: #e8eaed;
    --c-surface: #ffffff;
    --c-surface-hover: #f5f7fa;
    --c-border: #e0e0e0;
    --c-text: #1a1a2e;
    --c-text-secondary: #666688;
    --c-primary: #5e72e4;
    --c-primary-hover: #4f60d4;
    --c-primary-bg: rgba(94, 114, 228, 0.08);
    --c-danger: #e53e3e;
    --c-danger-bg: rgba(229, 62, 62, 0.06);
    --c-success: #38a169;
    --c-warning: #d69e2e;
    --c-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
    --star-color: 100, 100, 180;
    --star-opacity: 0.25;
    --meteor-color: 94, 114, 228;
}

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

body {
    font-family: var(--font-sans);
    color: var(--c-text);
    background: var(--c-bg);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
    transition: background 0.3s, color 0.3s;
}

#starfield-bg {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100%;
    z-index: 0;
    pointer-events: none;
}

/* ===== Login Screen ===== */
.login-screen {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    padding: 20px;
}

.login-card {
    background: var(--c-surface);
    border: 1px solid var(--c-border);
    border-radius: var(--radius);
    padding: 48px 40px;
    text-align: center;
    max-width: 400px;
    width: 100%;
    box-shadow: var(--c-shadow);
    position: relative;
    z-index: 1;
}

.login-icon {
    color: var(--c-primary);
    margin-bottom: 20px;
    display: flex;
    justify-content: center;
}

.login-card h1 {
    font-size: 1.6rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.login-subtitle {
    color: var(--c-text-secondary);
    font-size: 0.9rem;
    margin-bottom: 28px;
}

.login-form input {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--c-border);
    border-radius: var(--radius-sm);
    background: var(--c-bg);
    color: var(--c-text);
    font-size: 0.95rem;
    outline: none;
    transition: var(--transition);
    font-family: var(--font-sans);
}

.login-form input:focus {
    border-color: var(--c-primary);
    box-shadow: 0 0 0 3px var(--c-primary-bg);
}

.login-form button {
    width: 100%;
    margin-top: 16px;
    padding: 12px;
    border: none;
    border-radius: var(--radius-sm);
    background: var(--c-primary);
    color: #fff;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}

.login-form button:hover {
    background: var(--c-primary-hover);
    transform: translateY(-1px);
}

.login-error {
    color: var(--c-danger);
    font-size: 0.85rem;
    margin-top: 12px;
    min-height: 20px;
}

/* ===== Main App ===== */
.app {
    position: relative;
    z-index: 1;
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
}

/* Header */
.pan-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 0;
    margin-bottom: 24px;
    border-bottom: 1px solid var(--c-border);
}

.header-left {
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo-icon { font-size: 1.4rem; }
.logo-text { font-size: 1.2rem; font-weight: 700; }

.lanzou-badge {
    font-size: 0.65rem;
    background: rgba(94, 114, 228, 0.15);
    color: var(--c-primary);
    padding: 2px 8px;
    border-radius: 10px;
    font-weight: 500;
    margin-left: 4px;
}

.lanzou-status {
    font-size: 0.75rem;
    color: var(--c-success);
    padding: 2px 10px;
    border-radius: 10px;
    background: rgba(72, 187, 120, 0.1);
    border: 1px solid rgba(72, 187, 120, 0.2);
    max-width: 140px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 12px;
}

.storage-info {
    font-size: 0.8rem;
    color: var(--c-text-secondary);
}

.theme-toggle, .logout-btn, .settings-btn {
    background: var(--c-surface);
    border: 1px solid var(--c-border);
    border-radius: var(--radius-sm);
    width: 36px; height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--c-text);
    transition: var(--transition);
}

.theme-toggle:hover, .logout-btn:hover, .settings-btn:hover {
    background: var(--c-surface-hover);
    border-color: var(--c-primary);
}

/* Upload Zone */
.upload-container {
    margin-bottom: 32px;
}

.dropzone {
    border: 2px dashed var(--c-border);
    border-radius: var(--radius);
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    background: var(--c-surface);
}

.dropzone:hover, .dropzone.dragover {
    border-color: var(--c-primary);
    background: var(--c-primary-bg);
}

.dropzone.dragover {
    transform: scale(1.01);
}

.dropzone-icon {
    color: var(--c-text-secondary);
    margin-bottom: 12px;
    display: flex;
    justify-content: center;
}

.dropzone:hover .dropzone-icon {
    color: var(--c-primary);
}

.dropzone-text {
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: 4px;
}

.dropzone-hint {
    font-size: 0.8rem;
    color: var(--c-text-secondary);
}

/* Upload Progress */
.upload-progress-list {
    margin-top: 12px;
}

.upload-item {
    background: var(--c-surface);
    border: 1px solid var(--c-border);
    border-radius: var(--radius-sm);
    padding: 12px 16px;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.upload-item-info {
    flex: 1;
    min-width: 0;
}

.upload-item-name {
    font-size: 0.85rem;
    font-weight: 500;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.upload-item-status {
    font-size: 0.75rem;
    color: var(--c-text-secondary);
}

.progress-bar {
    width: 100%;
    height: 4px;
    background: var(--c-border);
    border-radius: 2px;
    overflow: hidden;
    margin-top: 6px;
}

.progress-bar-fill {
    height: 100%;
    background: var(--c-primary);
    border-radius: 2px;
    transition: width 0.2s;
}

/* File List */
.file-list-container {
    background: var(--c-surface);
    border: 1px solid var(--c-border);
    border-radius: var(--radius);
    overflow: hidden;
}

.file-list-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--c-border);
}

.file-list-header h2 {
    font-size: 1.1rem;
    font-weight: 600;
}

.refresh-btn {
    background: none;
    border: none;
    color: var(--c-text-secondary);
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
    transition: var(--transition);
}

.refresh-btn:hover {
    color: var(--c-primary);
    transform: rotate(180deg);
}

.file-list {
    min-height: 200px;
}

.file-empty {
    text-align: center;
    padding: 60px 20px;
    color: var(--c-text-secondary);
    font-size: 0.95rem;
}

.file-item {
    display: flex;
    align-items: center;
    padding: 12px 20px;
    border-bottom: 1px solid var(--c-border);
    transition: var(--transition);
    gap: 12px;
}

.file-item:last-child {
    border-bottom: none;
}

.file-item:hover {
    background: var(--c-surface-hover);
}

.file-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
    width: 32px;
    text-align: center;
}

.file-info {
    flex: 1;
    min-width: 0;
}

.file-name {
    font-size: 0.9rem;
    font-weight: 500;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.file-meta {
    font-size: 0.75rem;
    color: var(--c-text-secondary);
    display: flex;
    gap: 8px;
}

.file-actions {
    display: flex;
    gap: 6px;
    flex-shrink: 0;
}

.file-action-btn {
    background: none;
    border: 1px solid var(--c-border);
    border-radius: 6px;
    padding: 6px 10px;
    cursor: pointer;
    color: var(--c-text-secondary);
    font-size: 0.75rem;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 4px;
    font-family: var(--font-sans);
}

.file-action-btn:hover {
    border-color: var(--c-primary);
    color: var(--c-primary);
}

.file-action-btn.danger:hover {
    border-color: var(--c-danger);
    color: var(--c-danger);
    background: var(--c-danger-bg);
}

/* Modal */
.modal {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 200;
    padding: 20px;
}

.modal-content {
    background: var(--c-surface);
    border: 1px solid var(--c-border);
    border-radius: var(--radius);
    max-width: 500px;
    width: 100%;
    box-shadow: var(--c-shadow);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--c-border);
}

.modal-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--c-text-secondary);
    line-height: 1;
}

.modal-body {
    padding: 20px;
}

.share-filename {
    font-weight: 500;
    margin-bottom: 12px;
    word-break: break-all;
}

.share-link-box {
    display: flex;
    gap: 8px;
    margin-bottom: 8px;
}

.share-link-box input {
    flex: 1;
    padding: 10px 12px;
    border: 1px solid var(--c-border);
    border-radius: var(--radius-sm);
    background: var(--c-bg);
    color: var(--c-text);
    font-size: 0.85rem;
    outline: none;
    font-family: var(--font-sans);
}

.share-link-box input:focus {
    border-color: var(--c-primary);
}

.copy-btn {
    padding: 10px 16px;
    border: none;
    border-radius: var(--radius-sm);
    background: var(--c-primary);
    color: #fff;
    font-size: 0.85rem;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
    white-space: nowrap;
}

.copy-btn:hover {
    background: var(--c-primary-hover);
}

.share-hint {
    font-size: 0.75rem;
    color: var(--c-text-secondary);
    margin-bottom: 16px;
}

.share-actions {
    display: flex;
    gap: 8px;
}

.share-open-btn, .share-download-btn {
    flex: 1;
    text-align: center;
    padding: 10px;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    font-family: var(--font-sans);
    border: 1px solid var(--c-border);
}

.share-open-btn {
    background: var(--c-primary-bg);
    color: var(--c-primary);
    border-color: var(--c-primary);
}

.share-open-btn:hover {
    background: var(--c-primary);
    color: #fff;
}

.share-download-btn {
    background: var(--c-surface);
    color: var(--c-text);
}

.share-download-btn:hover {
    background: var(--c-surface-hover);
}

/* Toast */
.toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--c-surface);
    border: 1px solid var(--c-border);
    border-radius: var(--radius-sm);
    padding: 12px 24px;
    box-shadow: var(--c-shadow);
    z-index: 300;
    font-size: 0.9rem;
    animation: toastIn 0.3s ease;
}

.toast.success { border-color: var(--c-success); color: var(--c-success); }
.toast.error { border-color: var(--c-danger); color: var(--c-danger); }

@keyframes toastIn {
    from { opacity: 0; transform: translateX(-50%) translateY(10px); }
    to { opacity: 1; transform: translateX(-50%) translateY(0); }
}

/* ===== Setup Screen ===== */
.setup-card {
    max-width: 520px;
}

.setup-steps {
    text-align: left;
    margin-bottom: 20px;
    padding: 16px;
    background: var(--c-bg);
    border-radius: var(--radius-sm);
    font-size: 0.82rem;
    line-height: 2;
}

.step {
    display: flex;
    align-items: flex-start;
    gap: 8px;
    color: var(--c-text-secondary);
}

.step-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 20px; height: 20px;
    background: var(--c-primary);
    color: #fff;
    border-radius: 50%;
    font-size: 0.7rem;
    font-weight: 700;
    flex-shrink: 0;
    margin-top: 3px;
}

.step a {
    color: var(--c-primary);
    text-decoration: none;
}

.step code {
    background: var(--c-surface);
    padding: 1px 6px;
    border-radius: 4px;
    font-size: 0.78rem;
    word-break: break-all;
}

.setup-msg {
    margin-top: 12px;
    font-size: 0.85rem;
}

/* Login form textarea */
.login-form textarea, .settings-content textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--c-border);
    border-radius: var(--radius-sm);
    background: var(--c-bg);
    color: var(--c-text);
    font-size: 0.85rem;
    outline: none;
    transition: var(--transition);
    font-family: 'Courier New', monospace;
    resize: vertical;
    line-height: 1.5;
}

.login-form textarea:focus, .settings-content textarea:focus {
    border-color: var(--c-primary);
    box-shadow: 0 0 0 3px var(--c-primary-bg);
}

/* ===== Settings Modal ===== */
.settings-content {
    max-width: 560px;
}

.settings-actions {
    display: flex;
    gap: 8px;
    margin-top: 12px;
}

.btn-primary {
    flex: 1;
    padding: 10px;
    border: none;
    border-radius: var(--radius-sm);
    background: var(--c-primary);
    color: #fff;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}

.btn-primary:hover {
    background: var(--c-primary-hover);
}

.btn-danger {
    flex: 1;
    padding: 10px;
    border: 1px solid var(--c-danger);
    border-radius: var(--radius-sm);
    background: transparent;
    color: var(--c-danger);
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}

.btn-danger:hover {
    background: var(--c-danger-bg);
}

.settings-msg {
    margin-top: 12px;
    font-size: 0.85rem;
    min-height: 20px;
}

.settings-msg.success { color: var(--c-success); }
.settings-msg.error { color: var(--c-danger); }

.settings-hint {
    margin-top: 16px;
    padding: 12px;
    background: var(--c-bg);
    border-radius: var(--radius-sm);
    font-size: 0.78rem;
    color: var(--c-text-secondary);
    line-height: 1.7;
}

/* File meta password badge */
.has-pwd {
    color: var(--c-warning, #ecc94b);
    font-weight: 500;
    font-size: 0.7rem;
}
@media (max-width: 640px) {
    .app { padding: 12px; }
    .login-card { padding: 32px 24px; }
    .file-item { flex-wrap: wrap; }
    .file-actions { width: 100%; justify-content: flex-end; }
    .storage-info { display: none; }
    .dropzone { padding: 28px 16px; }
    .share-actions { flex-direction: column; }
}