:root {
    /* Color Palette - Premium Dark */
    --bg-app: #0f172a;
    --bg-card: #1e293b;
    --bg-card-hover: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;

    --primary: #6366f1;
    /* Indigo 500 */
    --primary-hover: #4f46e5;
    --accent: #10b981;
    /* Emerald 500 */
    --danger: #ef4444;

    --border-color: #334155;

    --nav-height: 70px;
    --header-height: 60px;

    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    -webkit-tap-highlight-color: transparent;
}

body {
    font-family: 'Outfit', sans-serif;
    background-color: var(--bg-app);
    color: var(--text-primary);
    line-height: 1.5;
    height: 100vh;
    height: 100dvh;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    /* Prevent body scroll, handle in main */
}

/* Authentication Screen */
#auth-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-app);
    z-index: 2000;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: opacity 0.3s ease;
}

#auth-screen.hidden {
    opacity: 0;
    pointer-events: none;
}

.auth-container {
    text-align: center;
    padding: 2rem;
}

/* App Container */
#app-container {
    display: flex;
    flex-direction: column;
    height: 100%;
}

.hidden {
    display: none !important;
}

/* Header */
.app-header {
    height: var(--header-height);
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(10px);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 1rem;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.app-header h1 {
    font-size: 1.25rem;
    font-weight: 600;
}

/* Main Content */
#main-content {
    flex: 1;
    overflow-y: auto;
    padding: 1rem;
    padding-bottom: calc(var(--nav-height) + 3rem);
}

/* Bottom Navigation */
.bottom-nav {
    height: var(--nav-height);
    background: var(--bg-card);
    display: flex;
    justify-content: space-around;
    align-items: center;
    position: fixed;
    bottom: 0;
    width: 100%;
    border-top: 1px solid var(--border-color);
    z-index: 100;
}

.nav-item {
    background: none;
    border: none;
    color: var(--text-secondary);
    display: flex;
    flex-direction: column;
    align-items: center;
    font-size: 0.75rem;
    gap: 4px;
    padding: 0.5rem;
    flex: 1;
    cursor: pointer;
    transition: color 0.2s;
}

.nav-item .icon {
    font-size: 1.5rem;
}

.nav-item.active {
    color: var(--primary);
}

.nav-item:active {
    transform: scale(0.95);
}

/* Components */
.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-hover));
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 12px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
    transition: transform 0.2s, box-shadow 0.2s;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.5rem;
}

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

.icon-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
}

.icon-btn:hover {
    background-color: var(--bg-card-hover);
}

/* Cards */
.card {
    background: var(--bg-card);
    border-radius: 16px;
    padding: 1rem;
    margin-bottom: 1rem;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.card h3 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

/* Forms */
.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

input,
textarea,
select {
    width: 100%;
    background: var(--bg-app);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.75rem;
    border-radius: 10px;
    font-family: inherit;
    font-size: 1rem;
}

input:focus,
textarea:focus,
select:focus {
    outline: none;
    border-color: var(--primary);
}

/* Lists */
.list-item {
    display: flex;
    align-items: center;
    background: var(--bg-card);
    padding: 1rem;
    margin-bottom: 0.75rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    gap: 1rem;
}

.list-item-content {
    flex: 1;
}

.list-item-title {
    font-weight: 600;
    display: block;
    margin-bottom: 0.25rem;
}

.list-item-subtitle {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

/* FAB (Floating Action Button) */
.fab {
    position: fixed;
    bottom: calc(var(--nav-height) + 20px);
    right: 20px;
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: var(--primary);
    color: white;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5rem;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
    border: none;
    z-index: 90;
    cursor: pointer;
}

/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    z-index: 1000;
    display: flex;
    justify-content: center;
    align-items: flex-end;
    /* Slide up from bottom on mobile */
}

.modal-content {
    background: var(--bg-card);
    width: 100%;
    max-width: 600px;
    /* Tablet limit */
    border-top-left-radius: 20px;
    border-top-right-radius: 20px;
    padding: 1.5rem;
    max-height: 90vh;
    /* Don't cover entire screen */
    overflow-y: auto;
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        transform: translateY(100%);
    }

    to {
        transform: translateY(0);
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.close-modal {
    background: none;
    border: none;
    font-size: 2rem;
    line-height: 1;
    color: var(--text-secondary);
    cursor: pointer;
}

/* Utilities */
.text-center {
    text-align: center;
}

.mb-1 {
    margin-bottom: 0.5rem;
}

.mb-2 {
    margin-bottom: 1rem;
}

.mt-2 {
    margin-top: 1rem;
}

.w-100 {
    width: 100%;
}

/* Active Workout Styles */
.sticky-top {
    position: sticky;
    top: 0;
    z-index: 99;
    backdrop-filter: blur(5px);
}

.custom-checkbox {
    display: inline-block;
    position: relative;
    padding-left: 35px;
    margin-bottom: 12px;
    cursor: pointer;
    font-size: 22px;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
    height: 30px;
    width: 30px;
}

.custom-checkbox input {
    position: absolute;
    opacity: 0;
    cursor: pointer;
    height: 0;
    width: 0;
}

.checkmark {
    position: absolute;
    top: 0;
    left: 0;
    height: 30px;
    width: 30px;
    background-color: var(--bg-app);
    border: 2px solid var(--text-secondary);
    border-radius: 6px;
}

.custom-checkbox:hover input~.checkmark {
    background-color: #ccc;
}

.custom-checkbox input:checked~.checkmark {
    background-color: var(--accent);
    border-color: var(--accent);
}

.checkmark:after {
    content: "";
    position: absolute;
    display: none;
}

.custom-checkbox input:checked~.checkmark:after {
    display: block;
}

.custom-checkbox .checkmark:after {
    left: 10px;
    top: 4px;
    width: 6px;
    height: 14px;
    border: solid white;
    border-width: 0 3px 3px 0;
    -webkit-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    transform: rotate(45deg);
}

.set-row {
    transition: opacity 0.3s;
}