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

:root {
    --primary: #2962ff;
    --primary-dark: #0039cb;
    --primary-light: #768fff;
    --accent: #00bfa5;
    --success: #00c853;
    --warning: #ffc400;
    --danger: #ff1744;
    
    --white: #ffffff;
    --gray-50: #f8f9fa;
    --gray-100: #f1f3f4;
    --gray-200: #e8eaed;
    --gray-300: #dadce0;
    --gray-400: #bdc1c6;
    --gray-500: #9aa0a6;
    --gray-600: #80868b;
    --gray-700: #5f6368;
    --gray-800: #3c4043;
    --gray-900: #202124;
    --black: #000000;
    
    --bg-app: #f8f9fa;
    --bg-surface: #ffffff;
    --bg-elevated: #ffffff;
    --bg-overlay: rgba(0, 0, 0, 0.5);
    
    --text-primary: #202124;
    --text-secondary: #5f6368;
    --text-tertiary: #9aa0a6;
    --text-inverse: #ffffff;
    
    --border-primary: #dadce0;
    --border-secondary: #e8eaed;
    --border-focus: #2962ff;
    
    /* Advanced Spacing System */
    --space-0: 0;
    --space-1: 0.25rem;    /* 4px */
    --space-2: 0.5rem;     /* 8px */
    --space-3: 0.75rem;    /* 12px */
    --space-4: 1rem;       /* 16px */
    --space-5: 1.25rem;    /* 20px */
    --space-6: 1.5rem;     /* 24px */
    --space-7: 1.75rem;    /* 28px */
    --space-8: 2rem;       /* 32px */
    --space-10: 2.5rem;    /* 40px */
    --space-12: 3rem;      /* 48px */
    --space-16: 4rem;      /* 64px */
    --space-20: 5rem;      /* 80px */
    
    /* Border Radius System */
    --radius-none: 0;
    --radius-sm: 6px;
    --radius: 8px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --radius-xl: 18px;
    --radius-2xl: 24px;
    --radius-full: 9999px;
    
    /* Premium Shadow System */
    --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.03);
    --shadow: 0 4px 8px rgba(0, 0, 0, 0.08), 0 2px 4px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 8px 16px rgba(0, 0, 0, 0.1), 0 4px 6px rgba(0, 0, 0, 0.05);
    --shadow-lg: 0 16px 32px rgba(0, 0, 0, 0.12), 0 8px 12px rgba(0, 0, 0, 0.06);
    --shadow-xl: 0 24px 48px rgba(0, 0, 0, 0.15), 0 12px 16px rgba(0, 0, 0, 0.08);
    
    /* Smooth Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', sans-serif;
    background: var(--bg-app);
    color: var(--text-primary);
    line-height: 1.5;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

/* ===========================
   LAYOUT
   =========================== */

.app {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background: linear-gradient(180deg, #f8f9fa 0%, #ffffff 100%);
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--space-8);
    width: 100%;
}


.header {
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border-secondary);
    padding: var(--space-10) 0;
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(20px);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--space-12);
    flex-wrap: wrap;
}

.brand {
    display: flex;
    align-items: center;
    gap: var(--space-6);
}

.brand-icon {
    width: 64px;
    height: 64px;
    flex-shrink: 0;
    object-fit: contain;
    filter: drop-shadow(0 2px 8px rgba(0, 0, 0, 0.1));
}

.brand-text h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--space-2);
    letter-spacing: -0.03em;
    color: var(--text-primary);
    line-height: 1.2;
}

.brand-text p {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 450;
    letter-spacing: -0.01em;
}

.header-stats {
    display: flex;
    gap: var(--space-12);
    align-items: center;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: var(--space-2);
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary);
    line-height: 1;
    letter-spacing: -0.04em;
    font-feature-settings: 'tnum';
}

.stat-label {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-top: 0;
    font-weight: 600;
}

.stat-divider {
    width: 1px;
    height: 56px;
    background: linear-gradient(to bottom, transparent, var(--border-primary), transparent);
}

.main {
    flex: 1;
    padding: var(--space-12) 0 var(--space-16) 0;
}

.controls {
    display: flex;
    gap: var(--space-5);
    margin-bottom: var(--space-10);
    flex-wrap: wrap;
    align-items: center;
}

.search-wrapper {
    position: relative;
    flex: 1;
    min-width: 320px;
    max-width: 580px;
}

.search-icon {
    position: absolute;
    left: var(--space-5);
    top: 50%;
    transform: translateY(-50%);
    width: 22px;
    height: 22px;
    color: var(--text-tertiary);
    pointer-events: none;
    transition: color var(--transition-base);
}

.search-input {
    width: 100%;
    padding: var(--space-4) var(--space-5) var(--space-4) 3.75rem;
    border: 2px solid var(--border-secondary);
    border-radius: var(--radius-full);
    font-size: 1rem;
    background: var(--bg-surface);
    color: var(--text-primary);
    transition: all var(--transition-base);
    font-family: inherit;
    font-weight: 450;
    box-shadow: var(--shadow-xs);
}

.search-input:hover {
    border-color: var(--border-primary);
    box-shadow: var(--shadow-sm);
}

.search-input:focus {
    outline: none;
    border-color: var(--border-focus);
    box-shadow: 0 0 0 4px rgba(41, 98, 255, 0.08), var(--shadow-sm);
}

.search-input:focus + .search-icon {
    color: var(--primary);
}

.search-input::placeholder {
    color: var(--text-tertiary);
}

.filter-group {
    display: flex;
    gap: var(--space-2);
    background: var(--bg-surface);
    padding: var(--space-2);
    border-radius: var(--radius-full);
    border: 2px solid var(--border-secondary);
    box-shadow: var(--shadow-xs);
}

.filter-btn {
    padding: var(--space-3) var(--space-6);
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.9375rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    cursor: pointer;
    transition: all var(--transition-base);
    font-family: inherit;
    letter-spacing: -0.01em;
}

.filter-btn:hover:not(.active) {
    background: var(--gray-100);
    color: var(--text-primary);
}

.filter-btn.active {
    background: var(--primary);
    color: var(--text-inverse);
    box-shadow: 0 2px 8px rgba(41, 98, 255, 0.25), 0 1px 3px rgba(41, 98, 255, 0.15);
}

.filter-count {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 24px;
    height: 20px;
    padding: 0 var(--space-2);
    margin-left: var(--space-2);
    background: var(--gray-200);
    color: var(--text-secondary);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 700;
    font-feature-settings: 'tnum';
}

.filter-btn.active .filter-count {
    background: rgba(255, 255, 255, 0.25);
    color: var(--text-inverse);
}

.leaderboard {
    background: var(--bg-surface);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    border: 1px solid var(--border-secondary);
}

.table-wrapper {
    overflow-x: auto;
    max-height: 650px;
    overflow-y: auto;
}

.table-wrapper::-webkit-scrollbar {
    width: 12px;
    height: 12px;
}

.table-wrapper::-webkit-scrollbar-track {
    background: var(--gray-50);
    border-radius: var(--radius);
}

.table-wrapper::-webkit-scrollbar-thumb {
    background: var(--gray-300);
    border-radius: var(--radius);
    border: 3px solid var(--gray-50);
    transition: background var(--transition-base);
}

.table-wrapper::-webkit-scrollbar-thumb:hover {
    background: var(--gray-400);
}

.table-wrapper::-webkit-scrollbar-corner {
    background: var(--gray-50);
}

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

.table thead {
    background: linear-gradient(180deg, #fafbfc 0%, #f5f6f7 100%);
    border-bottom: 2px solid var(--border-primary);
    position: sticky;
    top: 0;
    z-index: 10;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.table th {
    padding: var(--space-5) var(--space-6);
    text-align: left;
    font-size: 0.8125rem;
    font-weight: 700;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    white-space: nowrap;
}

.table th.th-center {
    text-align: center;
}

.table th.th-rank {
    width: 110px;
    padding-left: var(--space-8);
}

.table th.th-status {
    width: 180px;
}

.table tbody tr {
    border-bottom: 1px solid var(--border-secondary);
    transition: all var(--transition-base);
}

.table tbody tr:last-child {
    border-bottom: none;
}

.table tbody tr:hover {
    background: linear-gradient(90deg, rgba(41, 98, 255, 0.02) 0%, rgba(41, 98, 255, 0.04) 50%, rgba(41, 98, 255, 0.02) 100%);
    box-shadow: inset 3px 0 0 var(--primary);
}

.table td {
    padding: var(--space-6);
    font-size: 0.9375rem;
}

.table td.td-center {
    text-align: center;
}

.rank {
    display: inline-flex;
    align-items: center;
    gap: var(--space-4);
    font-weight: 700;
    font-size: 1.125rem;
}

.rank-number {
    color: var(--text-secondary);
    min-width: 36px;
    font-feature-settings: 'tnum';
}

.rank.top-1 .rank-number {
    color: #f9ab00;
    font-weight: 800;
    font-size: 1.25rem;
}

.rank.top-2 .rank-number {
    color: #9aa0a6;
    font-weight: 800;
    font-size: 1.25rem;
}

.rank.top-3 .rank-number {
    color: #e37400;
    font-weight: 800;
    font-size: 1.25rem;
}

.medal {
    font-size: 1.75rem;
    line-height: 1;
    filter: drop-shadow(0 1px 3px rgba(0, 0, 0, 0.15));
}

.user-info {
    display: flex;
    align-items: center;
    gap: var(--space-5);
}

.avatar {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, #2962ff 0%, #00bfa5 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
    font-size: 1rem;
    flex-shrink: 0;
    box-shadow: 0 4px 12px rgba(41, 98, 255, 0.25), inset 0 1px 0 rgba(255, 255, 255, 0.2);
    border: 2px solid white;
}

.user-details {
    min-width: 0;
    flex: 1;
}

.user-name {
    font-weight: 600;
    color: var(--text-primary);
    text-decoration: none;
    display: block;
    transition: color var(--transition-base);
    font-size: 1rem;
    line-height: 1.4;
    letter-spacing: -0.01em;
}

.user-name:hover {
    color: var(--primary);
    text-decoration: underline;
    text-decoration-thickness: 2px;
    text-underline-offset: 2px;
}

.user-email {
    font-size: 0.875rem;
    color: var(--text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    line-height: 1.4;
    margin-top: var(--space-1);
}

/* Badges */
.badge-count {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 48px;
    height: 40px;
    padding: 0 var(--space-4);
    background: var(--gray-100);
    color: var(--text-primary);
    border-radius: var(--radius-md);
    font-weight: 700;
    font-size: 1rem;
    font-feature-settings: 'tnum';
    box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.08);
}

.badge-count.high {
    background: linear-gradient(135deg, #e3f2fd 0%, #bbdefb 100%);
    color: #1565c0;
    box-shadow: inset 0 -1px 0 rgba(21, 101, 192, 0.15);
}

.badge-count.very-high {
    background: linear-gradient(135deg, #f3e5f5 0%, #e1bee7 100%);
    color: #6a1b9a;
    box-shadow: inset 0 -1px 0 rgba(106, 27, 154, 0.15);
}

/* Status Badge */
.status {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-5);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 600;
    line-height: 1.2;
    letter-spacing: -0.01em;
}

.status.completed {
    background: linear-gradient(135deg, #e8f5e9 0%, #c8e6c9 100%);
    color: #2e7d32;
    box-shadow: inset 0 -1px 0 rgba(46, 125, 50, 0.15);
}

.status.in-progress {
    background: linear-gradient(135deg, #fff8e1 0%, #ffecb3 100%);
    color: #f57c00;
    box-shadow: inset 0 -1px 0 rgba(245, 124, 0, 0.15);
}

.status.not-started {
    background: var(--gray-100);
    color: var(--text-secondary);
    box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.08);
}

/* Redeemed Badge */
.redeemed {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    font-size: 0.9375rem;
    font-weight: 700;
}

.redeemed.yes {
    background: linear-gradient(135deg, #e8f5e9 0%, #c8e6c9 100%);
    color: #2e7d32;
    box-shadow: inset 0 -1px 0 rgba(46, 125, 50, 0.15);
}

.redeemed.no {
    background: var(--gray-100);
    color: var(--text-tertiary);
    box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.08);
}

/* ===========================
   LOADING & EMPTY STATES
   =========================== */

.loading,
.empty {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-20);
    text-align: center;
}

.loader {
    width: 48px;
    height: 48px;
    border: 4px solid var(--gray-200);
    border-top-color: var(--primary);
    border-radius: var(--radius-full);
    animation: spin 0.7s linear infinite;
}

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

.loading p,
.empty p {
    margin-top: var(--space-6);
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 500;
}

.empty-icon {
    width: 72px;
    height: 72px;
    color: var(--gray-300);
}

/* ===========================
   FOOTER
   =========================== */

.footer {
    padding: var(--space-10) 0;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9375rem;
    border-top: 1px solid var(--border-secondary);
    background: var(--bg-surface);
    font-weight: 450;
}

/* ===========================
   RESPONSIVE DESIGN
   =========================== */

@media (max-width: 1024px) {
    .container {
        padding: 0 var(--space-6);
    }
}

@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-8);
    }
    
    .header-stats {
        width: 100%;
        justify-content: space-around;
        gap: var(--space-8);
    }
    
    .stat-item {
        align-items: center;
    }
    
    .brand-text h1 {
        font-size: 1.625rem;
    }
    
    .brand-icon {
        width: 52px;
        height: 52px;
    }
    
    .stat-number {
        font-size: 2rem;
    }
    
    .controls {
        flex-direction: column;
    }
    
    .search-wrapper {
        min-width: 100%;
        max-width: 100%;
    }
    
    .filter-group {
        width: 100%;
        justify-content: center;
    }
    
    .table th,
    .table td {
        padding: var(--space-4) var(--space-5);
        font-size: 0.875rem;
    }
    
    .table th.th-rank {
        padding-left: var(--space-5);
    }
    
    .avatar {
        width: 40px;
        height: 40px;
        font-size: 0.875rem;
    }
    
    .user-name {
        font-size: 0.9375rem;
    }
    
    .user-email {
        font-size: 0.8125rem;
    }
}

@media (max-width: 640px) {
    .container {
        padding: 0 var(--space-4);
    }
    
    .main {
        padding: var(--space-8) 0 var(--space-12) 0;
    }
    
    .header {
        padding: var(--space-8) 0;
    }
    
    .brand {
        gap: var(--space-4);
    }
    
    .brand-text h1 {
        font-size: 1.375rem;
    }
    
    .brand-text p {
        font-size: 0.875rem;
    }
    
    .brand-icon {
        width: 44px;
        height: 44px;
    }
    
    .stat-number {
        font-size: 1.75rem;
    }
    
    .stat-label {
        font-size: 0.75rem;
    }
    
    /* Keep all columns visible on mobile - optimize for horizontal scroll */
    .table-wrapper {
        max-height: 70vh;
    }
    
    .table th,
    .table td {
        padding: var(--space-3) var(--space-2);
        font-size: 0.8125rem;
        white-space: nowrap;
    }
    
    .table th.th-rank {
        width: 60px;
        padding-left: var(--space-3);
        padding-right: var(--space-2);
    }
    
    .table th.th-status {
        width: auto;
        min-width: 120px;
    }
    
    .rank {
        flex-direction: column;
        gap: var(--space-1);
        font-size: 1rem;
    }
    
    .rank-number {
        min-width: auto;
        font-size: 0.875rem;
    }
    
    .rank.top-1 .rank-number,
    .rank.top-2 .rank-number,
    .rank.top-3 .rank-number {
        font-size: 1rem;
    }
    
    .medal {
        font-size: 1.25rem;
    }
    
    .user-info {
        gap: var(--space-2);
        min-width: 160px;
    }
    
    .avatar {
        width: 32px;
        height: 32px;
        font-size: 0.75rem;
    }
    
    .user-name {
        font-size: 0.8125rem;
        line-height: 1.3;
    }
    
    .user-email {
        font-size: 0.6875rem;
    }
    
    .badge-count {
        min-width: 36px;
        height: 32px;
        padding: 0 var(--space-2);
        font-size: 0.875rem;
    }
    
    .status {
        padding: var(--space-2) var(--space-3);
        font-size: 0.75rem;
        white-space: nowrap;
    }
    
    .redeemed {
        width: 28px;
        height: 28px;
        font-size: 0.8125rem;
    }
}