:root {
    --bg: #ffffff;
    --surface: #f8fafc;
    --card: #ffffff;
    --border: #e2e8f0;
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --text: #0f172a;
    --text-secondary: #475569;
    --danger: #ef4444;
    --danger-hover: #dc2626;
    --success: #10b981;
    --nav-bg: rgba(255,255,255,0.8);
    --nav-border: rgba(226,232,240,0.8);
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.05);
    --radius: 16px;
    --radius-sm: 10px;
    --transition: 0.25s ease;
    --glass-bg: rgba(255,255,255,0.7);
    --glass-border: rgba(255,255,255,0.3);
    --input-bg: #ffffff;
    --input-border: #cbd5e1;
    --input-focus: #6366f1;
    --modal-overlay: rgba(0,0,0,0.45);
    --accent-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.dark {
    --bg: #0f172a;
    --surface: #1e293b;
    --card: #1e293b;
    --border: #334155;
    --primary: #818cf8;
    --primary-hover: #6366f1;
    --text: #f1f5f9;
    --text-secondary: #94a3b8;
    --danger: #f87171;
    --danger-hover: #ef4444;
    --success: #34d399;
    --nav-bg: rgba(15,23,42,0.8);
    --nav-border: rgba(51,65,85,0.6);
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
    --shadow: 0 4px 6px -1px rgba(0,0,0,0.4), 0 2px 4px -2px rgba(0,0,0,0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.5), 0 4px 6px -4px rgba(0,0,0,0.3);
    --glass-bg: rgba(30,41,59,0.7);
    --glass-border: rgba(51,65,85,0.5);
    --input-bg: #1e293b;
    --input-border: #475569;
    --input-focus: #818cf8;
    --modal-overlay: rgba(0,0,0,0.7);
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    transition: background var(--transition), color var(--transition);
}

/* NAVBAR */
.navbar {
    background: var(--nav-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--nav-border);
    padding: 0 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 66px;
    position: sticky;
    top: 0;
    z-index: 100;
    transition: background var(--transition), border-color var(--transition);
}
.navbar .brand {
    font-size: 1.4rem;
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    letter-spacing: -0.5px;
}
.nav-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}
.nav-links a {
    color: var(--text);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition);
    display: flex;
    align-items: center;
    gap: 0.35rem;
}
.nav-links a:hover { color: var(--primary); }

.theme-toggle {
    background: none;
    border: 1px solid var(--border);
    border-radius: 50px;
    width: 40px;
    height: 40px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    color: var(--text);
    transition: background var(--transition), border-color var(--transition);
    margin-left: 0.5rem;
}
.theme-toggle:hover { background: var(--surface); }

.logout-btn {
    background: var(--danger);
    color: white !important;
    padding: 0.5rem 1.2rem;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: background var(--transition);
    display: inline-flex !important;
}
.logout-btn:hover { background: var(--danger-hover); }

/* CONTAINER */
.container {
    flex: 1;
    max-width: 1280px;
    width: 100%;
    margin: 2rem auto;
    padding: 0 2rem;
}

/* CARDS */
.card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 2rem;
    margin-bottom: 1.5rem;
    backdrop-filter: blur(8px);
    transition: background var(--transition), border-color var(--transition), box-shadow var(--transition);
}
.card h2 {
    margin-bottom: 1rem;
    font-size: 1.75rem;
    font-weight: 700;
    background: linear-gradient(to right, var(--primary), #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* FORMS */
.form-group {
    margin-bottom: 1.2rem;
}
.form-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.35rem;
    color: var(--text);
}
.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.8rem 1rem;
    background: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    color: var(--text);
    transition: border-color var(--transition), box-shadow var(--transition);
    outline: none;
}
.form-group input:focus,
.form-group select:focus {
    border-color: var(--input-focus);
    box-shadow: 0 0 0 4px rgba(99,102,241,0.15);
}

/* BUTTONS */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    padding: 0.7rem 1.6rem;
    border: none;
    border-radius: 50px;
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    text-decoration: none;
    transition: all var(--transition);
    box-shadow: var(--shadow-sm);
}
.btn:active { transform: scale(0.97); }
.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover { background: var(--primary-hover); transform: translateY(-1px); box-shadow: var(--shadow); }
.btn-danger { background: var(--danger); color: white; }
.btn-danger:hover { background: var(--danger-hover); transform: translateY(-1px); }
.btn-success { background: var(--success); color: white; }
.btn-outline {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text);
}
.btn-outline:hover { background: var(--surface); }
.btn-sm { padding: 0.4rem 1rem; font-size: 0.8rem; }

/* TOOL GRID */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}
.tool-card {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius);
    padding: 1.8rem;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    box-shadow: var(--shadow-sm);
}
.tool-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}
.tool-card h3 {
    font-size: 1.25rem;
    color: var(--text);
}
.tool-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    flex: 1;
}

/* TABLES */
.table-responsive { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; margin-top: 1rem; }
th, td { padding: 1rem; text-align: left; border-bottom: 1px solid var(--border); }
th { background: var(--surface); font-weight: 600; color: var(--text); }
tr:hover { background: var(--surface); }

/* ALERTS */
.alert {
    padding: 1rem 1.3rem;
    border-radius: var(--radius-sm);
    margin-bottom: 1.5rem;
    font-weight: 500;
    border-left: 4px solid;
}
.alert-error { background: rgba(239,68,68,0.1); color: var(--danger); border-color: var(--danger); }
.alert-success { background: rgba(16,185,129,0.1); color: var(--success); border-color: var(--success); }

/* MODAL */
.modal {
    display: none;
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: var(--modal-overlay);
    justify-content: center;
    align-items: center;
    z-index: 200;
    backdrop-filter: blur(4px);
}
.modal .card { max-width: 420px; width: 90%; }

/* LOGIN PAGE */
.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: var(--bg);
    background-image: radial-gradient(circle at 50% 0%, var(--primary) 0%, transparent 70%);
    transition: background var(--transition);
}
.login-card {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius);
    padding: 3rem 2.5rem;
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 440px;
    transition: background var(--transition);
}
.login-card h1 {
    font-size: 2.5rem;
    font-weight: 800;
    text-align: center;
    margin-bottom: 2rem;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.login-card .theme-toggle {
    position: absolute;
    top: 2rem;
    right: 2rem;
    width: 44px;
    height: 44px;
    border: none;
    background: var(--surface);
}