/* =============================================================================
   STRONG - Premium Workout Tracker
   Award-Winning Design System
============================================================================= */

/* CSS Custom Properties (Design Tokens) */
:root {
    /* Colors - Modern, accessible palette */
    --color-primary: #6366f1;
    --color-primary-light: #8b8cf7;
    --color-primary-dark: #4f46e5;
    --color-secondary: #10b981;
    --color-secondary-light: #34d399;
    --color-secondary-dark: #059669;
    --color-danger: #ef4444;
    --color-danger-light: #f87171;
    --color-danger-dark: #dc2626;
    --color-warning: #f59e0b;
    --color-warning-light: #fbbf24;

    /* Neutrals */
    --color-white: #ffffff;
    --color-gray-50: #f9fafb;
    --color-gray-100: #f3f4f6;
    --color-gray-200: #e5e7eb;
    --color-gray-300: #d1d5db;
    --color-gray-400: #9ca3af;
    --color-gray-500: #6b7280;
    --color-gray-600: #4b5563;
    --color-gray-700: #374151;
    --color-gray-800: #1f2937;
    --color-gray-900: #111827;

    /* Background gradients */
    --bg-gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --bg-gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --bg-gradient-success: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);

    /* Spacing */
    --space-xs: 0.25rem; /* 4px */
    --space-sm: 0.5rem; /* 8px */
    --space-md: 1rem; /* 16px */
    --space-lg: 1.5rem; /* 24px */
    --space-xl: 2rem; /* 32px */
    --space-2xl: 3rem; /* 48px */
    --space-3xl: 4rem; /* 64px */

    /* Border radius */
    --radius-sm: 0.375rem; /* 6px */
    --radius-md: 0.5rem; /* 8px */
    --radius-lg: 0.75rem; /* 12px */
    --radius-xl: 1rem; /* 16px */
    --radius-2xl: 1.5rem; /* 24px */
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md:
        0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg:
        0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl:
        0 20px 25px -5px rgba(0, 0, 0, 0.1),
        0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);

    /* Typography */
    --font-family:
        "Inter", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
    --font-size-xs: 0.75rem; /* 12px */
    --font-size-sm: 0.875rem; /* 14px */
    --font-size-base: 1rem; /* 16px */
    --font-size-lg: 1.125rem; /* 18px */
    --font-size-xl: 1.25rem; /* 20px */
    --font-size-2xl: 1.5rem; /* 24px */
    --font-size-3xl: 1.875rem; /* 30px */
    --font-size-4xl: 2.25rem; /* 36px */
    --font-size-5xl: 3rem; /* 48px */

    /* Line heights */
    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;

    /* Transitions */
    --transition-fast: 150ms ease-out;
    --transition-normal: 250ms ease-out;
    --transition-slow: 350ms ease-out;

    /* Z-index layers */
    --z-dropdown: 1000;
    --z-modal: 2000;
    --z-toast: 3000;
    --z-loading: 4000;
}

/* =============================================================================
   BASE STYLES
============================================================================= */

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: var(--line-height-normal);
    color: var(--color-gray-900);
    background: var(--color-gray-50);
    overflow-x: hidden;
}

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

.app {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    position: relative;
}

/* Navigation Bar */
.nav-bar {
    background: var(--color-white);
    border-bottom: 1px solid var(--color-gray-200);
    padding: var(--space-md) 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(20px);
    background: rgba(255, 255, 255, 0.95);
}

.nav-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

.nav-logo {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-md);
}

.nav-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-gray-900);
    letter-spacing: -0.025em;
}

.nav-actions {
    display: flex;
    gap: var(--space-sm);
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
    border: none;
    border-radius: var(--radius-lg);
    font-weight: 500;
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: all var(--transition-normal);
}

.nav-btn svg {
    width: 16px;
    height: 16px;
}

.sync-btn {
    background: var(--color-primary);
    color: var(--color-white);
}

.sync-btn:hover {
    background: var(--color-primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.sync-btn:active {
    transform: translateY(0);
}

/* Main Content */
.main-content {
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--space-2xl) var(--space-lg);
    width: 100%;
}

/* =============================================================================
   SCREEN SYSTEM
============================================================================= */

.screen {
    display: none;
    animation: fadeIn var(--transition-normal) ease-out;
}

.screen.active {
    display: block;
}

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

.screen-header {
    text-align: center;
    margin-bottom: var(--space-3xl);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
    margin-bottom: var(--space-2xl);
}

.screen-title {
    font-size: var(--font-size-4xl);
    font-weight: 800;
    color: var(--color-gray-900);
    letter-spacing: -0.05em;
    line-height: var(--line-height-tight);
    margin-bottom: var(--space-sm);
}

.screen-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-gray-600);
    font-weight: 400;
}

/* Back Button */
.back-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    border: none;
    border-radius: var(--radius-full);
    background: var(--color-gray-100);
    color: var(--color-gray-700);
    cursor: pointer;
    transition: all var(--transition-normal);
}

.back-btn:hover {
    background: var(--color-gray-200);
    transform: translateX(-2px);
}

.back-btn svg {
    width: 20px;
    height: 20px;
}

/* =============================================================================
   WORKOUT SELECTION SCREEN
============================================================================= */

.workout-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-xl);
    margin-bottom: var(--space-3xl);
}

.workout-card {
    background: var(--color-white);
    border-radius: var(--radius-2xl);
    padding: var(--space-2xl);
    border: 1px solid var(--color-gray-200);
    cursor: pointer;
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.workout-card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--bg-gradient-primary);
    transform: scaleX(0);
    transition: transform var(--transition-normal);
}

.workout-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
    border-color: var(--color-primary-light);
}

.workout-card:hover::before {
    transform: scaleX(1);
}

.workout-card.active {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
    transform: translateY(-2px);
}

.workout-card.active::before {
    transform: scaleX(1);
}

.workout-card-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-gray-900);
    margin-bottom: var(--space-sm);
    letter-spacing: -0.025em;
}

.workout-card-meta {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
    margin-bottom: var(--space-md);
    font-size: var(--font-size-sm);
    color: var(--color-gray-600);
}

.workout-card-exercises {
    font-size: var(--font-size-sm);
    color: var(--color-gray-500);
    line-height: var(--line-height-relaxed);
}

/* Quick Actions */
.quick-actions {
    display: flex;
    gap: var(--space-lg);
    justify-content: center;
    flex-wrap: wrap;
}

.quick-action-btn {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    border: 2px solid var(--color-gray-300);
    border-radius: var(--radius-xl);
    background: var(--color-white);
    color: var(--color-gray-700);
    font-weight: 600;
    font-size: var(--font-size-base);
    cursor: pointer;
    transition: all var(--transition-normal);
}

.quick-action-btn svg {
    width: 20px;
    height: 20px;
}

.quick-action-btn:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.quick-action-btn.danger {
    border-color: var(--color-danger-light);
    color: var(--color-danger);
}

.quick-action-btn.danger:hover {
    border-color: var(--color-danger);
    background: var(--color-danger);
    color: var(--color-white);
}

/* =============================================================================
   WORKOUT SESSION SCREEN
============================================================================= */

.workout-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-2xl);
    padding-bottom: var(--space-lg);
    border-bottom: 1px solid var(--color-gray-200);
}

.workout-info {
    flex: 1;
    text-align: center;
}

.workout-name {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-gray-900);
    margin-bottom: var(--space-xs);
    letter-spacing: -0.025em;
}

.workout-progress {
    font-size: var(--font-size-sm);
    color: var(--color-gray-600);
    font-weight: 500;
}

.save-btn {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-lg);
    border: none;
    border-radius: var(--radius-xl);
    background: var(--color-secondary);
    color: var(--color-white);
    font-weight: 600;
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: all var(--transition-normal);
}

.save-btn:hover {
    background: var(--color-secondary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.save-btn svg {
    width: 16px;
    height: 16px;
}

/* Bottom Save Button */
.bottom-save-container {
    margin-top: var(--space-2xl);
    padding-top: var(--space-xl);
    border-top: 1px solid var(--color-gray-200);
    display: block;
}

.bottom-save-btn {
    width: 100%;
    justify-content: center;
    padding: var(--space-lg) var(--space-xl);
    font-size: var(--font-size-base);
}

/* Exercises Container */
.exercises-container {
    display: flex;
    flex-direction: column;
    gap: var(--space-xl);
}

/* Exercise Card */
.exercise {
    background: var(--color-white);
    border-radius: var(--radius-2xl);
    padding: var(--space-2xl);
    border: 1px solid var(--color-gray-200);
    transition: all var(--transition-normal);
    position: relative;
}

.exercise:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

.exercise-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-lg);
}

.exercise-title {
    flex: 1;
}

.exercise-name {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-gray-900);
    margin-bottom: var(--space-xs);
    letter-spacing: -0.025em;
}

.exercise-target {
    font-size: var(--font-size-sm);
    color: var(--color-gray-600);
    font-weight: 500;
}

.exercise-controls {
    display: flex;
    gap: var(--space-sm);
}

.exercise-control-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border: 1px solid var(--color-gray-300);
    border-radius: var(--radius-lg);
    background: var(--color-white);
    color: var(--color-gray-600);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: var(--font-size-lg);
    font-weight: 600;
}

.exercise-control-btn:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    background: var(--color-gray-50);
}

.exercise-control-btn:active {
    transform: scale(0.95);
}

/* Master Input */
.master-input {
    margin-bottom: var(--space-lg);
}

.master-input input {
    width: 100%;
    padding: var(--space-md);
    border: 1px solid var(--color-gray-300);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    background: var(--color-gray-50);
    transition: all var(--transition-normal);
}

.master-input input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
    background: var(--color-white);
}

/* Sets Container */
.sets {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.set-container {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md);
    background: var(--color-gray-50);
    border-radius: var(--radius-lg);
    transition: all var(--transition-normal);
    flex-wrap: nowrap;
}

.set-inputs {
    display: flex;
    gap: var(--space-sm);
    flex: 1;
    min-width: 0;
}

.set-container:hover {
    background: var(--color-white);
    box-shadow: var(--shadow-sm);
}

.set-btn {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
    border: 2px solid var(--color-gray-300);
    border-radius: var(--radius-lg);
    background: var(--color-white);
    color: var(--color-gray-700);
    font-weight: 600;
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: all var(--transition-normal);
    min-width: 80px;
}

.set-btn:hover {
    border-color: var(--color-primary-light);
    color: var(--color-primary);
}

.set-btn.completed {
    border-color: var(--color-secondary);
    background: var(--color-secondary);
    color: var(--color-white);
}

.set-btn::before {
    content: "";
    width: 16px;
    height: 16px;
    border: 2px solid currentColor;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.set-btn.completed::before {
    background: var(--color-white);
    border-color: var(--color-white);
    background-image: url("data:image/svg+xml,%3csvg viewBox='0 0 16 16' fill='%2310b981' xmlns='http://www.w3.org/2000/svg'%3e%3cpath d='m13.854 3.646-7.5 7.5a.5.5 0 0 1-.708 0l-3.5-3.5a.5.5 0 1 1 .708-.708L6 10.293l7.146-7.147a.5.5 0 0 1 .708.708z'/%3e%3c/svg%3e");
}

/* Set Inputs */
.set-input {
    flex: 1 1 auto;
    padding: var(--space-sm) var(--space-md);
    border: 1px solid var(--color-gray-300);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    background: var(--color-white);
    transition: all var(--transition-normal);
    min-width: 50px;
    max-width: none;
}

.set-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.1);
}

.set-input::placeholder {
    color: var(--color-gray-400);
}

/* =============================================================================
   HISTORY SCREEN
============================================================================= */

.history-container {
    display: flex;
    flex-direction: column;
    gap: var(--space-xl);
}

.history-entry {
    background: var(--color-white);
    border-radius: var(--radius-2xl);
    padding: var(--space-2xl);
    border: 1px solid var(--color-gray-200);
    transition: all var(--transition-normal);
}

.history-entry:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

.history-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--space-lg);
    padding-bottom: var(--space-md);
    border-bottom: 1px solid var(--color-gray-200);
}

.history-info h3 {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-gray-900);
    margin-bottom: var(--space-xs);
    letter-spacing: -0.025em;
}

.history-date {
    font-size: var(--font-size-sm);
    color: var(--color-gray-600);
    font-weight: 500;
}

.history-actions {
    display: flex;
    gap: var(--space-sm);
}

.history-btn {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-xs) var(--space-sm);
    border: 1px solid var(--color-gray-300);
    border-radius: var(--radius-md);
    background: var(--color-white);
    font-size: var(--font-size-xs);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-normal);
}

.history-btn svg {
    width: 14px;
    height: 14px;
}

.history-btn:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.history-btn.edit {
    color: var(--color-primary);
    border-color: var(--color-primary-light);
}

.history-btn.delete {
    color: var(--color-danger);
    border-color: var(--color-danger-light);
}

.history-btn.delete:hover {
    background: var(--color-danger);
    color: var(--color-white);
}

.history-exercises {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-md);
}

.history-exercise {
    background: var(--color-gray-50);
    padding: var(--space-md);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-gray-200);
}

.history-exercise-name {
    font-weight: 600;
    color: var(--color-gray-900);
    margin-bottom: var(--space-xs);
    font-size: var(--font-size-sm);
}

.history-exercise-details {
    font-size: var(--font-size-xs);
    color: var(--color-gray-600);
    line-height: var(--line-height-relaxed);
    margin-bottom: var(--space-sm);
}

.history-exercise-details br {
    margin-bottom: var(--space-xs);
}

.history-exercise-summary {
    font-size: var(--font-size-xs);
    color: var(--color-gray-500);
    font-weight: 600;
    padding: var(--space-xs) var(--space-sm);
    background: var(--color-gray-100);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--color-secondary);
    margin-top: var(--space-sm);
}

/* =============================================================================
   EDIT SCREEN
============================================================================= */

.editing-mode {
    position: relative;
}

.editing-mode::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(
        90deg,
        var(--color-primary),
        var(--color-secondary)
    );
    border-radius: 0 0 var(--radius-sm) var(--radius-sm);
    z-index: 1;
}

.editing-indicator {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-size: var(--font-size-xs);
    color: var(--color-primary);
    font-weight: 600;
    margin-top: var(--space-xs);
}

.editing-indicator svg {
    width: 16px;
    height: 16px;
    opacity: 0.8;
}

.edit-date-section {
    background: var(--color-white);
    border-radius: var(--radius-2xl);
    padding: var(--space-2xl);
    margin-bottom: var(--space-xl);
    border: 1px solid var(--color-gray-200);
    border-left: 4px solid var(--color-primary);
}

.edit-date-label {
    display: block;
    font-weight: 600;
    color: var(--color-gray-900);
    margin-bottom: var(--space-sm);
    font-size: var(--font-size-sm);
}

.edit-date-input {
    width: 100%;
    padding: var(--space-md);
    border: 1px solid var(--color-gray-300);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    font-family: inherit;
    transition: all var(--transition-normal);
    background: var(--color-white);
}

.edit-date-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
    background: var(--color-white);
}

.edit-date-input::placeholder {
    color: var(--color-gray-500);
}

.editing-mode .exercise {
    border-left: 4px solid var(--color-primary-light);
    background: linear-gradient(
        135deg,
        var(--color-white) 0%,
        rgba(59, 130, 246, 0.02) 100%
    );
}

.editing-mode .exercise:hover {
    border-left-color: var(--color-primary);
    transform: translateY(-1px);
}

.editing-mode .set-container {
    background: rgba(59, 130, 246, 0.05);
    border: 1px solid var(--color-primary-light);
}

.editing-mode .set-container:hover {
    background: var(--color-white);
    border-color: var(--color-primary);
}

.editing-mode .set-btn.completed {
    background: var(--color-primary);
    color: var(--color-white);
    border-color: var(--color-primary);
}

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

.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(17, 24, 39, 0.75);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: var(--z-modal);
    padding: var(--space-lg);
    animation: modalFadeIn var(--transition-normal) ease-out;
}

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

.modal-content {
    background: var(--color-white);
    border-radius: var(--radius-2xl);
    padding: var(--space-2xl);
    max-width: 600px;
    width: 100%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: var(--shadow-2xl);
    animation: modalSlideIn var(--transition-normal) ease-out;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(20px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-xl);
    padding-bottom: var(--space-md);
    border-bottom: 1px solid var(--color-gray-200);
}

.modal-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-gray-900);
}

.modal-close {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border: none;
    border-radius: var(--radius-full);
    background: var(--color-gray-100);
    color: var(--color-gray-600);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--color-gray-200);
    color: var(--color-gray-800);
}

.modal-close svg {
    width: 16px;
    height: 16px;
}

.modal-footer {
    display: flex;
    gap: var(--space-md);
    justify-content: flex-end;
    margin-top: var(--space-xl);
    padding-top: var(--space-md);
    border-top: 1px solid var(--color-gray-200);
}

.modal-btn {
    padding: var(--space-md) var(--space-xl);
    border: none;
    border-radius: var(--radius-lg);
    font-weight: 600;
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: all var(--transition-normal);
}

.modal-btn.primary {
    background: var(--color-primary);
    color: var(--color-white);
}

.modal-btn.primary:hover {
    background: var(--color-primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.modal-btn.secondary {
    background: var(--color-gray-100);
    color: var(--color-gray-700);
    border: 1px solid var(--color-gray-300);
}

.modal-btn.secondary:hover {
    background: var(--color-gray-200);
}

/* =============================================================================
   LOADING & TOAST SYSTEM
============================================================================= */

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: var(--z-loading);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

.loading-overlay.active {
    opacity: 1;
    visibility: visible;
}

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

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--color-gray-200);
    border-top: 3px solid var(--color-primary);
    border-radius: var(--radius-full);
    animation: spin 1s linear infinite;
    margin: 0 auto var(--space-md);
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
}

.loading-text {
    color: var(--color-gray-600);
    font-weight: 500;
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    top: var(--space-lg);
    right: var(--space-lg);
    z-index: var(--z-toast);
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.toast {
    background: var(--color-white);
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-xl);
    padding: var(--space-md) var(--space-lg);
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: var(--space-md);
    max-width: 400px;
    animation: toastSlideIn var(--transition-normal) ease-out;
}

@keyframes toastSlideIn {
    from {
        opacity: 0;
        transform: translateX(100%);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.toast.success {
    border-color: var(--color-secondary-light);
    background: var(--color-white);
}

.toast.error {
    border-color: var(--color-danger-light);
    background: var(--color-white);
}

.toast.warning {
    border-color: var(--color-warning-light);
    background: var(--color-white);
}

.toast-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

.toast.success .toast-icon {
    color: var(--color-secondary);
}

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

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

.toast-message {
    color: var(--color-gray-900);
    font-weight: 500;
    font-size: var(--font-size-sm);
}

/* =============================================================================
   FLOATING ACTION BUTTON
============================================================================= */

.fab-container {
    position: fixed;
    bottom: var(--space-2xl);
    right: var(--space-2xl);
    z-index: 500;
}

.fab {
    width: 56px;
    height: 56px;
    border: none;
    border-radius: var(--radius-full);
    background: var(--bg-gradient-primary);
    color: var(--color-white);
    box-shadow: var(--shadow-lg);
    cursor: pointer;
    transition: all var(--transition-normal);
    display: flex;
    align-items: center;
    justify-content: center;
}

.fab:hover {
    transform: translateY(-2px) scale(1.05);
    box-shadow: var(--shadow-xl);
}

.fab:active {
    transform: translateY(0) scale(0.95);
}

.fab svg {
    width: 24px;
    height: 24px;
}

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

/* Tablet Styles */
@media (max-width: 1024px) {
    .main-content {
        padding: var(--space-xl) var(--space-md);
    }

    .workout-grid {
        grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
        gap: var(--space-lg);
    }

    .workout-card {
        padding: var(--space-xl);
    }

    .exercise {
        padding: var(--space-xl);
    }

    .history-exercises {
        grid-template-columns: 1fr;
    }
}

/* Mobile Styles */
@media (max-width: 768px) {
    .nav-content {
        padding: 0 var(--space-md);
    }

    .nav-title {
        font-size: var(--font-size-lg);
    }

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

    .screen-title {
        font-size: var(--font-size-3xl);
    }

    .screen-subtitle {
        font-size: var(--font-size-base);
    }

    .workout-grid {
        grid-template-columns: 1fr;
        gap: var(--space-md);
    }

    .workout-card {
        padding: var(--space-lg);
    }

    .workout-card-title {
        font-size: var(--font-size-lg);
    }

    .quick-actions {
        flex-direction: column;
        gap: var(--space-md);
    }

    .quick-action-btn {
        width: 100%;
        justify-content: center;
        padding: var(--space-lg);
    }

    .workout-header {
        flex-direction: column;
        gap: var(--space-md);
        text-align: center;
    }

    .workout-info {
        order: 1;
    }

    .back-btn {
        order: 0;
        align-self: flex-start;
    }

    .save-btn {
        order: 2;
        align-self: stretch;
        justify-content: center;
        padding: var(--space-md) var(--space-lg);
    }

    .exercise {
        padding: var(--space-lg);
    }

    .exercise-header {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-md);
    }

    .exercise-controls {
        align-self: flex-end;
    }

    .set-container {
        gap: var(--space-sm);
        padding: var(--space-sm);
    }

    .set-inputs {
        gap: var(--space-xs);
    }

    .set-btn {
        flex-shrink: 0;
        min-width: 60px;
        padding: var(--space-xs) var(--space-sm);
        font-size: var(--font-size-xs);
    }

    .set-input {
        flex: 1 1 auto;
        min-width: 35px;
        padding: var(--space-xs) var(--space-sm);
        font-size: var(--font-size-xs);
    }

    .bottom-save-container {
        display: block;
    }

    .history-header {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-md);
    }

    .history-actions {
        align-self: flex-end;
    }

    .modal-content {
        margin: var(--space-md);
        padding: var(--space-lg);
    }

    .edit-date-section {
        padding: var(--space-lg);
    }

    .editing-indicator {
        font-size: var(--font-size-xs);
    }

    .editing-indicator svg {
        width: 14px;
        height: 14px;
    }

    .modal-footer {
        flex-direction: column;
        gap: var(--space-sm);
    }

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

    .toast-container {
        top: var(--space-md);
        right: var(--space-md);
        left: var(--space-md);
    }

    .toast {
        max-width: none;
    }

    .fab-container {
        bottom: var(--space-lg);
        right: var(--space-lg);
    }
}

/* Small Mobile Styles */
@media (max-width: 480px) {
    .nav-content {
        padding: 0 var(--space-sm);
    }

    .nav-logo {
        width: 28px;
        height: 28px;
    }

    .nav-title {
        font-size: var(--font-size-base);
    }

    .nav-btn span {
        display: none;
    }

    .nav-btn {
        padding: var(--space-sm);
    }

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

    .screen-title {
        font-size: var(--font-size-2xl);
    }

    .workout-card {
        padding: var(--space-md);
    }

    .exercise {
        padding: var(--space-md);
    }

    .exercise-name {
        font-size: var(--font-size-lg);
    }

    .history-entry {
        padding: var(--space-md);
    }

    .modal-content {
        padding: var(--space-md);
    }

    .edit-date-section {
        padding: var(--space-md);
    }

    .edit-date-input {
        font-size: var(--font-size-sm);
    }

    .set-container {
        gap: var(--space-xs);
        padding: var(--space-xs);
    }

    .set-inputs {
        gap: 2px;
    }

    .set-btn {
        min-width: 50px;
        padding: var(--space-xs);
        font-size: var(--font-size-xs);
    }

    .set-input {
        min-width: 30px;
        padding: var(--space-xs);
        font-size: var(--font-size-xs);
    }
}

/* =============================================================================
   UTILITIES
============================================================================= */

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.hidden {
    display: none !important;
}

.fade-enter {
    opacity: 0;
    transform: translateY(20px);
}

.fade-enter-active {
    opacity: 1;
    transform: translateY(0);
    transition: all var(--transition-normal);
}

.fade-exit {
    opacity: 1;
    transform: translateY(0);
}

.fade-exit-active {
    opacity: 0;
    transform: translateY(-20px);
    transition: all var(--transition-normal);
}

/* Dark mode support (future enhancement) */
@media (prefers-color-scheme: dark) {
    :root {
        --color-gray-50: #1f2937;
        --color-gray-100: #374151;
        --color-gray-200: #4b5563;
        --color-gray-300: #6b7280;
        --color-gray-400: #9ca3af;
        --color-gray-500: #d1d5db;
        --color-gray-600: #e5e7eb;
        --color-gray-700: #f3f4f6;
        --color-gray-800: #f9fafb;
        --color-gray-900: #ffffff;
        --color-white: #111827;
    }

    body {
        background: var(--color-gray-50);
    }

    .nav-bar {
        background: rgba(31, 41, 55, 0.95);
        border-bottom-color: var(--color-gray-200);
    }
}

/* Print styles */
@media print {
    .nav-bar,
    .fab-container,
    .toast-container,
    .loading-overlay {
        display: none !important;
    }

    .main-content {
        padding: 0;
        max-width: none;
    }

    .workout-card,
    .exercise,
    .history-entry {
        break-inside: avoid;
        box-shadow: none !important;
        border: 1px solid var(--color-gray-300) !important;
    }
}