/* ===========================
   CSS VARIABLES & RESET
   =========================== */

:root {
    /* Colors */
    --primary: #1f2937;
    --primary-light: #374151;
    --accent: #ff6b35;
    --accent-light: #ff8c5a;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --border: #e5e7eb;
    --success: #10b981;
    --danger: #ef4444;
    --warning: #f59e0b;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.875rem;
    --radius-xl: 1.25rem;

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 8px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 16px rgba(0, 0, 0, 0.12);

    /* Transitions */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    font-size: 16px;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===========================
   TYPOGRAPHY
   =========================== */

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
}

h2 {
    font-size: 1.75rem;
}

h3 {
    font-size: 1.25rem;
}

p {
    color: var(--text-secondary);
    margin: var(--spacing-md) 0;
}

a {
    color: var(--primary);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--primary-dark);
}

/* ===========================
   NAVBAR
   =========================== */

.navbar {
    position: sticky;
    top: 0;
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border);
    padding: var(--spacing-lg) var(--spacing-md);
    z-index: 100;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
}

.nav-left {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary);
    letter-spacing: -0.5px;
}

.menu-btn, .back-btn, .add-btn {
    background: var(--bg-secondary);
    border: none;
    color: var(--text-primary);
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    font-size: 1.25rem;
}

.menu-btn:active, .back-btn:active, .add-btn:active {
    transform: scale(0.95);
}

.menu-btn:hover, .back-btn:hover {
    background-color: var(--bg-tertiary);
}

.add-btn {
    background: var(--accent);
    border: none;
    color: white;
    font-weight: 600;
}

.add-btn:hover {
    background: var(--accent-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(255, 107, 53, 0.2);
}

/* ===========================
   MOBILE MENU
   =========================== */

.mobile-menu {
    position: fixed;
    left: -100%;
    top: 0;
    width: 80%;
    max-width: 280px;
    height: 100vh;
    background-color: var(--bg-primary);
    transition: left 0.3s ease;
    z-index: 99;
    padding-top: 80px;
    border-right: 1px solid var(--border);
    overflow-y: auto;
    box-shadow: 2px 0 8px rgba(0, 0, 0, 0.1);
}

.mobile-menu.active {
    left: 0;
}

.menu-nav {
    display: flex;
    flex-direction: column;
}

.menu-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    padding: var(--spacing-lg) var(--spacing-xl);
    color: var(--text-secondary);
    border-left: 3px solid transparent;
    transition: var(--transition);
    font-weight: 500;
}

.menu-link:hover,
.menu-link.active {
    background-color: var(--bg-secondary);
    color: var(--accent);
    border-left-color: var(--accent);
}

/* ===========================
   MAIN CONTENT
   =========================== */

.main-content {
    min-height: calc(100vh - 60px - 100px);
    padding: var(--spacing-xl) var(--spacing-md);
    padding-bottom: var(--spacing-2xl);
    animation: fadeIn 0.5s ease;
    background-color: var(--bg-primary);
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.container {
    max-width: 520px;
    margin: 0 auto;
}

/* ===========================
   SECTIONS
   =========================== */

.welcome-section {
    margin-bottom: var(--spacing-2xl);
    padding-bottom: var(--spacing-xl);
}

.welcome-section h2 {
    margin-bottom: var(--spacing-sm);
    font-size: 2rem;
    font-weight: 800;
    color: var(--primary);
}

.welcome-section p {
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 500;
}

/* Stats Section */
.stats-section {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-2xl);
}

@media (min-width: 768px) {
    .stats-section {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .stats-section .stat-card:nth-child(3) {
        grid-column: 1 / -1;
    }
}

.stat-card {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    background-color: var(--bg-secondary);
    border: 1px solid var(--border);
    padding: var(--spacing-lg);
    border-radius: var(--radius-xl);
    transition: var(--transition);
    cursor: pointer;
    animation: slideUp 0.5s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.stat-card:hover {
    background-color: var(--bg-tertiary);
    border-color: var(--accent);
    transform: translateY(-4px);
    box-shadow: 0 8px 16px rgba(255, 107, 53, 0.1);
}

.stat-icon {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    flex-shrink: 0;
    background: linear-gradient(135deg, var(--accent), var(--accent-light));
}

.stat-content {
    flex: 1;
}

.stat-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0;
    color: var(--primary);
}

/* Section Headers */
.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xl);
}

.section-header h3 {
    margin: 0;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary);
}

.view-all {
    font-size: 0.9rem;
    color: var(--accent);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-weight: 600;
    transition: var(--transition);
}

.view-all:hover {
    color: var(--accent-light);
}

/* Recent/Workouts Section */
.recent-section, .workouts-section {
    margin-top: var(--spacing-2xl);
}

/* ===========================
   WORKOUTS LIST
   =========================== */

.workouts-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.workout-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    transition: var(--transition);
    animation: slideUp 0.5s ease;
}

.workout-card:hover {
    background-color: var(--bg-tertiary);
    border-color: var(--accent);
    box-shadow: 0 8px 16px rgba(255, 107, 53, 0.08);
}

.workout-card-header {
    display: flex;
    justify-content: space-between;
    align-items: start;
    margin-bottom: var(--spacing-lg);
}

.workout-card-title {
    font-size: 1.1rem;
    font-weight: 700;
    margin: 0;
    color: var(--primary);
}

.workout-card-date {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 500;
    margin-top: var(--spacing-xs);
}

.workout-card-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border);
}

.stat-item {
    text-align: center;
}

.stat-item-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-xs);
}

.stat-item-value {
    font-size: 1.25rem;
    font-weight: 700;
    margin: 0;
}

.workout-card-actions {
    display: flex;
    gap: var(--spacing-sm);
}

.workout-card-actions button {
    flex: 1;
}

/* ===========================
   FILTERS SECTION
   =========================== */

.filters-section {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
}

.filter-group {
    flex: 1;
    min-width: 150px;
}

/* ===========================
   BUTTONS
   =========================== */

.btn {
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.btn:active {
    transform: scale(0.98);
}

.btn-primary {
    background: var(--accent);
    color: white;
    border: none;
}

.btn-primary:hover {
    background: var(--accent-light);
    box-shadow: 0 4px 12px rgba(255, 107, 53, 0.3);
    transform: translateY(-2px);
}

.btn-secondary {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background-color: var(--bg-tertiary);
    border-color: var(--accent);
    color: var(--accent);
}

.btn-danger {
    background-color: var(--danger);
    color: white;
    border: none;
}

.btn-danger:hover {
    opacity: 0.9;
    box-shadow: 0 4px 12px rgba(239, 68, 68, 0.3);
    transform: translateY(-2px);
}

.btn-block {
    width: 100%;
    margin: var(--spacing-md) 0;
}

.btn-sm {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.875rem;
}

.btn-icon {
    width: 40px;
    height: 40px;
    padding: 0;
}

/* ===========================
   FORMS
   =========================== */

.workout-form {
    animation: slideUp 0.5s ease;
}

.form-group {
    margin-bottom: var(--spacing-xl);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 700;
    color: var(--primary);
    font-size: 0.95rem;
}

.form-input {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    background-color: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1rem;
    transition: var(--transition);
}

.form-input::placeholder {
    color: var(--text-muted);
}

.form-input:focus {
    outline: none;
    border-color: var(--accent);
    background-color: var(--bg-tertiary);
    box-shadow: 0 0 0 3px rgba(255, 107, 53, 0.1);
}

.form-input[type="date"] {
    cursor: pointer;
}

.form-error {
    color: var(--danger);
    font-size: 0.875rem;
    margin-top: var(--spacing-sm);
    display: none;
}

.form-error.show {
    display: block;
}

/* ===========================
   EMPTY STATE
   =========================== */

.empty-state {
    text-align: center;
    padding: var(--spacing-2xl) var(--spacing-lg);
    background-color: var(--bg-secondary);
    border: 2px dashed var(--border);
    border-radius: var(--radius-xl);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.empty-state i {
    font-size: 3.5rem;
    color: var(--accent);
    margin-bottom: var(--spacing-lg);
    opacity: 0.3;
}

.empty-state p {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-lg);
    color: var(--text-secondary);
    font-weight: 500;
}

/* ===========================
   MODAL
   =========================== */

.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.4);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: var(--spacing-lg);
    animation: fadeIn 0.3s ease;
}

.modal.active {
    display: flex;
}

.modal-content {
    background-color: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    max-width: 400px;
    width: 100%;
    animation: slideUp 0.3s ease;
    box-shadow: 0 16px 32px rgba(0, 0, 0, 0.15);
}

.modal-content h3 {
    margin-bottom: var(--spacing-md);
    color: var(--primary);
    font-weight: 700;
}

.modal-content p {
    margin-bottom: var(--spacing-lg);
    color: var(--text-secondary);
    line-height: 1.6;
}

.modal-actions {
    display: flex;
    gap: var(--spacing-md);
}

.modal-actions button {
    flex: 1;
}

/* ===========================
   TOAST NOTIFICATION
   =========================== */

.toast {
    position: fixed;
    bottom: -100px;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--primary);
    color: white;
    padding: var(--spacing-lg) var(--spacing-xl);
    border-radius: var(--radius-md);
    border: none;
    border-left: 4px solid var(--success);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
    transition: bottom 0.3s ease;
    z-index: 999;
    max-width: 90%;
    text-align: center;
    font-weight: 600;
}

.toast.show {
    bottom: 20px;
}

.toast.error {
    border-left-color: var(--danger);
}

.toast.warning {
    border-left-color: var(--warning);
}

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

.footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border);
    padding: var(--spacing-2xl) var(--spacing-md);
    text-align: center;
    font-size: 0.875rem;
    color: var(--text-muted);
}

.footer p {
    margin-bottom: var(--spacing-md);
    font-weight: 500;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
}

.social-links a {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--bg-tertiary);
    border-radius: var(--radius-md);
    transition: var(--transition);
    color: var(--text-primary);
}

.social-links a:hover {
    background: var(--accent);
    color: white;
    transform: translateY(-4px);
    box-shadow: 0 4px 12px rgba(255, 107, 53, 0.2);
}

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

@media (max-width: 480px) {
    :root {
        font-size: 14px;
    }

    .nav-container {
        padding: var(--spacing-sm);
    }

    .logo {
        font-size: 1.25rem;
    }

    .main-content {
        padding: var(--spacing-md);
    }

    .stat-card {
        flex-direction: column;
        text-align: center;
    }

    .stat-icon {
        width: 50px;
        height: 50px;
    }

    .stats-section {
        grid-template-columns: 1fr;
    }

    .filters-section {
        flex-direction: column;
    }

    .filter-group {
        min-width: auto;
    }
}

@media (min-width: 768px) {
    .main-content {
        padding: var(--spacing-xl) var(--spacing-md);
    }

    .container {
        max-width: 600px;
    }

    .stats-section {
        gap: var(--spacing-md);
    }

    .stat-card {
        flex-direction: row;
    }
}

@media (min-width: 1024px) {
    .container {
        max-width: 800px;
    }
}

/* ===========================
   UTILITY CLASSES
   =========================== */

.hidden {
    display: none !important;
}

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

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
a svg {
  width: 24px;
  height: 24px;
  fill: #fff;
  transition: 0.3s;
}

a:hover svg {
  transform: scale(1.2);
  fill: #00ffcc;
}