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

:root {
    --primary: #0f3460;
    --secondary: #16c784;
    --accent: #00d4ff;
    --dark: #0a1929;
    --light: #f5f7fa;
    --border: #1e293b;
    --text: #e2e8f0;
    --error: #ff6b6b;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--dark);
    color: var(--text);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
header {
    background: linear-gradient(135deg, var(--primary) 0%, #1a4d7a 100%);
    padding: 1.5rem 0;
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-right {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--secondary), var(--accent));
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    cursor: pointer;
}

/* Main Layout */
.main-layout {
    display: flex;
    min-height: calc(100vh - 70px);
}

.sidebar {
    width: 250px;
    background: var(--primary);
    border-right: 1px solid var(--border);
    padding: 2rem 0;
    position: fixed;
    height: calc(100vh - 70px);
    overflow-y: auto;
}

.sidebar-menu {
    list-style: none;
}

.sidebar-menu li {
    margin: 0;
}

.sidebar-menu a {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 1.5rem;
    color: var(--text);
    text-decoration: none;
    transition: all 0.3s ease;
    border-left: 3px solid transparent;
    cursor: pointer;
}

.sidebar-menu a:hover,
.sidebar-menu a.active {
    background: rgba(0, 212, 255, 0.1);
    border-left-color: var(--accent);
    color: var(--accent);
}

.content {
    flex: 1;
    margin-left: 250px;
    padding: 2rem;
}

/* Forms */
.form-container {
    background: var(--primary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 2rem;
    max-width: 500px;
}

.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text);
}

input,
textarea,
select {
    width: 100%;
    padding: 0.75rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border);
    border-radius: 6px;
    color: var(--text);
    font-size: 1rem;
    transition: all 0.3s ease;
}

input:focus,
textarea:focus,
select:focus {
    outline: none;
    border-color: var(--accent);
    background: rgba(0, 212, 255, 0.05);
    box-shadow: 0 0 0 3px rgba(0, 212, 255, 0.1);
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.btn-primary {
    background: linear-gradient(135deg, var(--secondary), var(--accent));
    color: var(--dark);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(22, 199, 132, 0.3);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
}

.btn-danger {
    background: rgba(239, 68, 68, 0.15);
    color: #ef4444;
    border: 1px solid rgba(239, 68, 68, 0.4);
}

.btn-danger:hover {
    background: rgba(239, 68, 68, 0.25);
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

/* Cards */
.card {
    background: var(--primary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    transition: all 0.3s ease;
}

.card:hover {
    border-color: var(--accent);
    box-shadow: 0 8px 24px rgba(0, 212, 255, 0.15);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border);
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
}

/* Upload Area */
.upload-area {
    border: 2px dashed var(--border);
    border-radius: 8px;
    padding: 3rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
}

.upload-area:hover,
.upload-area.drag-over {
    border-color: var(--accent);
    background: rgba(0, 212, 255, 0.05);
}

.upload-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

/* Dashboard Grid */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: linear-gradient(135deg, rgba(22, 199, 132, 0.1), rgba(0, 212, 255, 0.1));
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.5rem;
    text-align: center;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--secondary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    color: var(--text);
    margin-top: 0.5rem;
    font-size: 0.875rem;
}

/* Table */
.table-container {
    overflow-x: auto;
    border-radius: 8px;
    border: 1px solid var(--border);
}

table {
    width: 100%;
    border-collapse: collapse;
}

th {
    background: rgba(0, 212, 255, 0.05);
    padding: 1rem;
    text-align: left;
    font-weight: 600;
    border-bottom: 1px solid var(--border);
    color: var(--accent);
}

td {
    padding: 1rem;
    border-bottom: 1px solid var(--border);
}

tr:hover {
    background: rgba(0, 212, 255, 0.05);
}

/* Alerts */
.alert {
    padding: 1rem;
    border-radius: 6px;
    margin-bottom: 1rem;
    border-left: 4px solid;
}

.alert-success {
    background: rgba(22, 199, 132, 0.1);
    border-left-color: var(--secondary);
    color: var(--secondary);
}

.alert-error {
    background: rgba(255, 107, 107, 0.1);
    border-left-color: var(--error);
    color: var(--error);
}

.alert-info {
    background: rgba(0, 212, 255, 0.1);
    border-left-color: var(--accent);
    color: var(--accent);
}

.hidden {
    display: none !important;
}

/* Login Page */
.login-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #0f3460 0%, #16407b 100%);
}

.login-container {
    width: 100%;
    padding: 20px;
}

.login-box {
    background: var(--primary);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 2.5rem;
    max-width: 400px;
    margin: 0 auto;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.login-title {
    font-size: 1.75rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--accent), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.login-subtitle {
    text-align: center;
    color: #94a3b8;
    margin-bottom: 2rem;
    font-size: 0.95rem;
}

.btn-block {
    width: 100%;
    justify-content: center;
}

.page-view {
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@media (max-width: 768px) {
    .sidebar {
        width: 100%;
        height: auto;
        position: static;
        padding: 1rem 0;
    }

    .content {
        margin-left: 0;
        padding: 1rem;
    }

    .dashboard-grid {
        grid-template-columns: 1fr;
    }
}