/* ===== CSS RESET & VARIABLES ===== */
:root {
    /* Light theme (default) */
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-card: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #334155;
    --text-muted: #64748b;
    --accent: #2563eb;
    --accent-light: #3b82f6;
    --accent-dark: #1d4ed8;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --danger-dark: #dc2626;
    --border: #e2e8f0;
    --border-dark: #cbd5e1;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --radius-sm: 0.375rem;
    --radius: 0.5rem;
    --radius-lg: 0.75rem;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --transition: all 0.2s ease;
}

.dark-theme {
    --bg-primary: #0b1120;
    --bg-secondary: #1e293b;
    --bg-card: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border: #334155;
    --border-dark: #475569;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.5);
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
    transition: background-color 0.3s, color 0.3s;
}

/* ===== TYPOGRAPHY ===== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

h1 { font-size: 2rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.25rem; }

p { margin-bottom: 1rem; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ===== BUTTONS ===== */
button {
    cursor: pointer;
    font-family: inherit;
    font-size: 0.875rem;
    font-weight: 500;
    padding: 0.625rem 1.25rem;
    border-radius: var(--radius-sm);
    border: 1px solid transparent;
    transition: var(--transition);
    background: none;
}

.btn-primary {
    background-color: var(--accent);
    color: white;
    border-color: var(--accent);
}
.btn-primary:hover {
    background-color: var(--accent-dark);
    border-color: var(--accent-dark);
}
.btn-secondary {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    border-color: var(--border);
}
.btn-secondary:hover {
    background-color: var(--border);
}
.btn-outline {
    background-color: transparent;
    color: var(--accent);
    border-color: var(--accent);
}
.btn-outline:hover {
    background-color: var(--accent);
    color: white;
}
.btn-danger {
    background-color: var(--danger);
    color: white;
    border-color: var(--danger);
}
.btn-danger:hover {
    background-color: var(--danger-dark);
}
.btn-text {
    background: none;
    border: none;
    color: var(--accent);
    padding: 0.5rem;
}
.btn-text:hover {
    background-color: rgba(37, 99, 235, 0.1);
    text-decoration: underline;
}
.btn-icon {
    padding: 0.5rem;
    border-radius: 9999px;
    color: var(--text-secondary);
    background: transparent;
    border: none;
}
.btn-icon:hover {
    background-color: var(--border);
}
.btn-small {
    padding: 0.375rem 0.75rem;
    font-size: 0.75rem;
}
.btn-large {
    padding: 0.875rem 1.5rem;
    font-size: 1rem;
}

/* ===== FORMS ===== */
.form-group {
    margin-bottom: 1.25rem;
}
label {
    display: block;
    margin-bottom: 0.375rem;
    font-weight: 500;
    color: var(--text-secondary);
    font-size: 0.875rem;
}
input, select, textarea {
    width: 100%;
    padding: 0.625rem 0.875rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 0.9375rem;
    transition: var(--transition);
}
input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}
.form-group.checkbox {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.form-group.checkbox label {
    margin-bottom: 0;
}
input[type="checkbox"] {
    width: auto;
    margin-right: 0.5rem;
}
.error-message {
    color: var(--danger);
    font-size: 0.75rem;
    margin-top: 0.25rem;
}
small, .small {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* ===== CARDS ===== */
.card {
    background-color: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
}

/* ===== LOADING OVERLAY & SPINNER ===== */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    transition: opacity 0.3s;
}
.loading-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}
.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}
@keyframes spin {
    to { transform: rotate(360deg); }
}
.page-transition-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--bg-primary);
    z-index: 9998;
    display: none;
}

/* ===== TOAST NOTIFICATIONS ===== */
.toast-container {
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    z-index: 10000;
}
.toast {
    background-color: var(--bg-card);
    color: var(--text-primary);
    padding: 0.875rem 1.25rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    margin-top: 0.75rem;
    border-left: 4px solid var(--accent);
    display: flex;
    align-items: center;
    gap: 0.75rem;
    animation: slideIn 0.3s ease;
    max-width: 350px;
}
.toast.success { border-left-color: var(--success); }
.toast.error { border-left-color: var(--danger); }
.toast.warning { border-left-color: var(--warning); }
.toast.info { border-left-color: var(--accent); }
@keyframes slideIn {
    from { transform: translateX(100%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

/* ===== MODAL ===== */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10001;
}
.modal {
    background-color: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    max-width: 500px;
    width: 90%;
    box-shadow: var(--shadow-lg);
}
.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}
.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-muted);
}
.modal-footer {
    margin-top: 1.5rem;
    display: flex;
    justify-content: flex-end;
    gap: 0.75rem;
}

/* ===== TABS ===== */
.tabs {
    display: flex;
    border-bottom: 2px solid var(--border);
    margin-bottom: 1.5rem;
    gap: 0.5rem;
}
.tab-button {
    padding: 0.625rem 1.25rem;
    background: none;
    border: none;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    color: var(--text-secondary);
    font-weight: 500;
}
.tab-button.active {
    color: var(--accent);
    border-bottom-color: var(--accent);
}
.tab-content {
    display: none;
}
.tab-content.active {
    display: block;
}

/* ===== BADGES ===== */
.badge {
    display: inline-block;
    padding: 0.25rem 0.5rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 500;
    background-color: var(--bg-secondary);
    color: var(--text-secondary);
    border: 1px solid var(--border);
}

/* ===== PROGRESS BAR ===== */
.progress-bar {
    height: 8px;
    background-color: var(--border);
    border-radius: 9999px;
    overflow: hidden;
}
.progress-fill {
    height: 100%;
    background-color: var(--accent);
    transition: width 0.3s ease;
}

/* ===== UTILITIES ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}
.text-center { text-align: center; }
.text-right { text-align: right; }
.hidden { display: none !important; }
.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-1 { gap: 0.5rem; }
.gap-2 { gap: 1rem; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.p-1 { padding: 0.5rem; }
.p-2 { padding: 1rem; }