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

:root {
    --primary: #4f46e5;
    --background: #0f172a;
    --surface: #1e293b;
    --text: #f1f5f9;
    --text-secondary: #94a3b8;
    --border: #334155;
    --error: #ef4444;
    --shadow: rgba(0, 0, 0, 0.3);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: linear-gradient(135deg, var(--background) 0%, #1e293b 100%);
    color: var(--text);
    min-height: 100vh;
    line-height: 1.6;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
}

/* Auth Screen */
.auth-screen {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
}

.auth-box {
    background: var(--surface);
    border-radius: 16px;
    padding: 40px;
    box-shadow: 0 20px 50px var(--shadow);
    width: 100%;
    max-width: 400px;
    text-align: center;
}

.auth-box h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

.tagline {
    color: var(--text-secondary);
    margin-bottom: 30px;
}

#authForm input {
    width: 100%;
    padding: 14px;
    margin-bottom: 12px;
    border: 2px solid var(--border);
    border-radius: 8px;
    background: var(--background);
    color: var(--text);
    font-size: 15px;
}

/* Auth buttons */
.auth-screen .primary-btn,
.auth-screen .secondary-btn {
    width: 140px;
    padding: 10px 0;
    font-size: 16px;
    line-height: 1.2;
    text-align: center;
    border-radius: 6px;
    margin-right: 10px;
    margin-top: 16px;
    box-sizing: border-box;
}

.primary-btn {
    background: var(--primary);
    color: white;
    border: 2px solid var(--primary);
}

.primary-btn:hover {
    filter: brightness(1.1);
}

.secondary-btn {
    background: transparent;
    color: var(--text);
    border: 2px solid var(--border);
}

.secondary-btn:hover {
    background: var(--border);
    color: var(--text);
}

.highlight-btn {
    background: transparent;
    color: var(--primary);
    border: 2px solid var(--primary);
}

.highlight-btn:hover {
    background: var(--primary);
    color: white;
    transition: 0.2s;
}

/* Main App */
.app-screen { display: block; }
.hidden { display: none !important; }

header {
    background: var(--surface);
    border-radius: 12px;
    padding: 20px 30px;
    margin-bottom: 30px;
    box-shadow: 0 4px 12px var(--shadow);
}

.header-content { display: flex; justify-content: space-between; align-items: center; gap: 20px; }
.header-right { display: flex; align-items: center; gap: 15px; flex: 1; justify-content: flex-end; }

.header-search {
    max-width: 300px;
    width: 100%;
    padding: 10px 16px;
    border: 2px solid var(--border);
    border-radius: 8px;
    background: var(--background);
    color: var(--text);
    font-size: 14px;
}

.user-dropdown { position: relative; }
.user-icon-btn {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 2px solid var(--border);
    background: var(--surface);
    color: var(--text);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
}

.dropdown-menu {
    position: absolute;
    top: calc(100% + 10px);
    right: 0;
    background: var(--surface);
    border: 2px solid var(--border);
    border-radius: 12px;
    box-shadow: 0 8px 24px var(--shadow);
    min-width: 200px;
    z-index: 1000;
    overflow: hidden;
}

.dropdown-header {
    padding: 12px 16px;
    border-bottom: 1px solid var(--border);
    background: var(--background);
}

.user-email-dropdown { color: var(--text-secondary); font-size: 13px; }
.dropdown-item { width: 100%; padding: 12px 16px; border: none; background: transparent; color: var(--text); text-align: left; display: flex; align-items: center; gap: 10px; font-size: 14px; }

header h1 { font-size: 1.8rem; white-space: nowrap; }
.home-link { color: var(--text); text-decoration: none; cursor: pointer; }

/* Add Link Section */
.add-link-section {
    background: var(--surface);
    border-radius: 12px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 4px 12px var(--shadow);
}

.input-group {
    display: flex;
    gap: 12px;
}

.input-group input {
    flex: 1;
    padding: 14px;
    border: 2px solid var(--border);
    border-radius: 8px;
    background: var(--background);
    color: var(--text);
    font-size: 16px;
}

.input-group .primary-btn {
    min-width: 120px;
    padding: 14px 24px;
    font-size: 16px;
    line-height: normal;
    border-radius: 8px;
    text-align: center;
}

/* Links Container */
.links-container { display: grid; gap: 20px; }

.empty-state { text-align: center; padding: 60px 20px; color: var(--text-secondary); }

.link-card {
    background: var(--surface);
    border-radius: 12px;
    padding: 24px;
    box-shadow: 0 4px 12px var(--shadow);
}

.link-header { display: flex; justify-content: space-between; align-items: flex-start; margin-bottom: 12px; }
.link-title { font-size: 1.2rem; font-weight: 600; color: var(--text); display: flex; align-items: flex-start; gap: 8px; }

.link-icon { color: var(--primary); text-decoration: none; margin-top: 2px; }
.link-summary { color: var(--text-secondary); margin: 16px 0; line-height: 1.6; }

.link-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; align-items: center; }
.link-date { color: var(--text-secondary); font-size: 13px; margin-left: auto; white-space: nowrap; }

.tag { background: var(--background); color: #cbd5e1; padding: 6px 12px; border-radius: 6px; font-size: 13px; font-weight: 500; }

.delete-btn {
    background: transparent;
    border: none;
    color: var(--error);
    cursor: pointer;
    font-size: 20px;
    padding: 0;
}

/* Error Messages */
.error-message { color: var(--error); font-size: 14px; margin-top: 10px; text-align: center; }

@keyframes spin { to { transform: rotate(360deg); } }

/* Responsive */
@media (max-width: 768px) { .header-search { max-width: 200px; } }
@media (max-width: 600px) {
    .container { padding: 15px; }
    .auth-box { padding: 30px 20px; }
    header { padding: 15px 20px; }
    .header-content { flex-wrap: wrap; gap: 10px; }
    .header-right { flex: 1 1 100%; justify-content: space-between; }
    .header-search { max-width: none; flex: 1; }
    .input-group { flex-direction: column; }
    .input-group .primary-btn { width: 100%; }
}