/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #7868E6;
    --primary-light: #B8B5FF;
    --secondary: #EDEEF7;
    --accent: #E4FBFF;
    --danger: #FFB4B4;
    --text-dark: #2c2c2c;
    --text-light: #666;
    --white: #ffffff;
    --shadow: rgba(120, 104, 230, 0.1);
    --border-radius: 16px;
    --transition: all 0.3s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, var(--secondary) 0%, var(--accent) 100%);
    color: var(--text-dark);
    line-height: 1.6;
    min-height: 100vh;
    position: relative;
    padding-bottom: 63px;
}

/* Paper Texture Effect */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        radial-gradient(circle at 1px 1px, rgba(255,255,255,0.15) 1px, transparent 0);
    background-size: 20px 20px;
    pointer-events: none;
    z-index: -1;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    background: var(--white);
    box-shadow: 0 2px 20px var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    text-shadow: 0 2px 4px var(--shadow);
}



.nav {
    display: flex;
    gap: 10px;
}

.nav-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    padding: 8px 12px;
    background: transparent;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-light);
    font-size: 0.8rem;
}

.nav-btn:hover,
.nav-btn.active {
    background: var(--primary-light);
    color: var(--primary);
    transform: translateY(-2px);
}

.nav-icon {
    font-size: 1.2rem;
}

.nav-text {
    font-size: 0.7rem;
    font-weight: 500;
}

/* Main Content */
.main {
    padding: 20px 0 80px;
    min-height: calc(100vh - 140px);
}

.section {
    display: none;
    animation: fadeIn 0.3s ease;
}

.section.active {
    display: block;
}

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

/* Cards */
.welcome-card {
    background: var(--white);
    padding: 24px;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 20px var(--shadow);
    margin-bottom: 24px;
    text-align: center;
}

.welcome-card h2 {
    color: var(--primary);
    margin-bottom: 8px;
    font-size: 1.4rem;
}

.welcome-card p {
    color: var(--text-light);
    font-size: 1rem;
}

/* Hydration Tracker */
.hydration-tracker {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 24px;
}

.goal-display,
.intake-display {
    background: var(--white);
    padding: 24px;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 20px var(--shadow);
    text-align: center;
}

.goal-display h3,
.intake-display h3 {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.goal-amount,
.intake-amount {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 16px;
}

/* Progress Ring */
.progress-ring {
    position: relative;
    display: inline-block;
}

.progress-svg {
    transform: rotate(-90deg);
}

.progress-bg {
    fill: none;
    stroke: var(--secondary);
    stroke-width: 8;
}

.progress-fill {
    fill: none;
    stroke: var(--primary);
    stroke-width: 8;
    stroke-linecap: round;
    stroke-dasharray: 314;
    stroke-dashoffset: 314;
    transition: stroke-dashoffset 0.5s ease;
}

.progress-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--primary);
}

.remaining {
    color: var(--text-light);
    font-size: 0.9rem;
}

/* Glass Selector */
.glass-selector {
    background: var(--white);
    padding: 24px;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 20px var(--shadow);
    margin-bottom: 24px;
}

.glass-selector h3 {
    color: var(--text-dark);
    margin-bottom: 16px;
    text-align: center;
}

.glass-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
    gap: 12px;
    margin-bottom: 20px;
}

.glass-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    padding: 16px 8px;
    background: var(--secondary);
    border: 2px solid transparent;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.8rem;
}

.glass-btn:hover {
    background: var(--primary-light);
    border-color: var(--primary);
    transform: translateY(-2px);
}

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

.glass-icon {
    font-size: 2rem;
}

.glass-amount {
    font-weight: 700;
    color: var(--primary);
}

.glass-label {
    color: var(--text-light);
    font-size: 0.7rem;
}

/* Custom Amount */
.custom-amount {
    border-top: 1px solid var(--secondary);
    padding-top: 20px;
}

.custom-amount label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-dark);
    font-weight: 500;
}

.input-group {
    display: flex;
    gap: 8px;
}

.input-group input {
    flex: 1;
    padding: 12px;
    border: 2px solid var(--secondary);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.input-group input:focus {
    outline: none;
    border-color: var(--primary);
}

.input-group button {
    padding: 12px 20px;
    background: var(--primary);
    color: var(--white);
    border: none;
    border-radius: var(--border-radius);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.input-group button:hover {
    background: var(--primary-light);
    transform: translateY(-1px);
}

/* Today Log */
.today-log {
    background: var(--white);
    padding: 24px;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 20px var(--shadow);
}

.today-log h3 {
    color: var(--text-dark);
    margin-bottom: 16px;
    text-align: center;
}

.entries-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
    max-height: 200px;
    overflow-y: auto;
}

.entry-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px;
    background: var(--secondary);
    border-radius: 8px;
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from { opacity: 0; transform: translateX(-20px); }
    to { opacity: 1; transform: translateX(0); }
}

.entry-amount {
    font-weight: 600;
    color: var(--primary);
}

.entry-time {
    color: var(--text-light);
    font-size: 0.9rem;
}

.entry-delete {
    background: var(--danger);
    color: var(--white);
    border: none;
    border-radius: 50%;
    width: 24px;
    height: 24px;
    cursor: pointer;
    font-size: 0.8rem;
    transition: var(--transition);
}

.entry-delete:hover {
    transform: scale(1.1);
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.stat-card {
    background: var(--white);
    padding: 20px;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 20px var(--shadow);
    text-align: center;
}

.stat-card h3 {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 4px;
}

.stat-label {
    color: var(--text-light);
    font-size: 0.8rem;
}

/* Chart Container */
.chart-container {
    background: var(--white);
    padding: 24px;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 20px var(--shadow);
    margin-bottom: 24px;
}

.chart-container h3 {
    color: var(--text-dark);
    margin-bottom: 16px;
    text-align: center;
}

#weeklyChart {
    width: 100%;
    height: auto;
}

/* Achievements */
.achievements {
    background: var(--white);
    padding: 24px;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 20px var(--shadow);
}

.achievements h3 {
    color: var(--text-dark);
    margin-bottom: 16px;
    text-align: center;
}

.achievements-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 12px;
}

.achievement-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px;
    background: var(--secondary);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.achievement-item.unlocked {
    background: var(--primary-light);
    color: var(--primary);
}

.achievement-icon {
    font-size: 1.5rem;
}

.achievement-text {
    flex: 1;
}

.achievement-title {
    font-weight: 600;
    margin-bottom: 2px;
}

.achievement-desc {
    font-size: 0.8rem;
    color: var(--text-light);
}

/* Settings */
.settings-group {
    background: var(--white);
    padding: 24px;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 20px var(--shadow);
    margin-bottom: 24px;
}

.settings-group h3 {
    color: var(--text-dark);
    margin-bottom: 16px;
    border-bottom: 2px solid var(--secondary);
    padding-bottom: 8px;
}

.setting-item {
    margin-bottom: 16px;
}

.setting-item label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-dark);
    font-weight: 500;
}

.setting-item input,
.setting-item select {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--secondary);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

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

.setting-item small {
    color: var(--text-light);
    font-size: 0.8rem;
    margin-top: 4px;
    display: block;
}

/* Toggle Switch */
.toggle-label {
    display: flex !important;
    align-items: center;
    gap: 12px;
    cursor: pointer;
}

.toggle-label input {
    display: none;
}

.toggle-slider {
    width: 50px;
    height: 26px;
    background: var(--secondary);
    border-radius: 13px;
    position: relative;
    transition: var(--transition);
}

.toggle-slider::before {
    content: '';
    position: absolute;
    width: 22px;
    height: 22px;
    background: var(--white);
    border-radius: 50%;
    top: 2px;
    left: 2px;
    transition: var(--transition);
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.toggle-label input:checked + .toggle-slider {
    background: var(--primary);
}

.toggle-label input:checked + .toggle-slider::before {
    transform: translateX(24px);
}

/* Buttons */
.setting-buttons {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.btn-secondary,
.btn-danger {
    padding: 12px 24px;
    border: none;
    border-radius: var(--border-radius);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
}

.btn-secondary {
    background: var(--secondary);
    color: var(--text-dark);
}

.btn-secondary:hover {
    background: var(--primary-light);
    color: var(--primary);
}

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

.btn-danger:hover {
    background: #ff9999;
    transform: translateY(-1px);
}

/* FAQ */
.faq-list {
    margin-bottom: 24px;
}

.faq-item {
    background: var(--white);
    border-radius: var(--border-radius);
    box-shadow: 0 4px 20px var(--shadow);
    margin-bottom: 12px;
    overflow: hidden;
}

.faq-question {
    width: 100%;
    padding: 20px;
    background: transparent;
    border: none;
    text-align: left;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-dark);
    transition: var(--transition);
}

.faq-question:hover {
    background: var(--secondary);
}

.faq-icon {
    font-size: 1.2rem;
    color: var(--primary);
    transition: var(--transition);
}

.faq-question[aria-expanded="true"] .faq-icon {
    transform: rotate(45deg);
}

.faq-answer {
    padding: 0 20px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
}

.faq-answer.open {
    padding: 0 20px 20px;
    max-height: 200px;
}

.faq-answer p {
    color: var(--text-light);
    line-height: 1.6;
}

/* Disclaimer */
.disclaimer {
    background: var(--danger);
    color: var(--white);
    padding: 24px;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 20px var(--shadow);
}

.disclaimer h3 {
    margin-bottom: 12px;
}

.disclaimer p {
    line-height: 1.6;
}

/* Footer */
.footer {
    background: var(--white);
    padding: 20px 0;
    text-align: center;
    box-shadow: 0 -2px 20px var(--shadow);
    margin-top: auto;
}

.footer p {
    color: var(--text-light);
    font-size: 0.9rem;
}

.footer a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 600;
}

.footer a:hover {
    text-decoration: underline;
}

/* Toast Notifications */
.toast {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--primary);
    color: var(--white);
    padding: 16px 24px;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 20px var(--shadow);
    z-index: 1000;
    opacity: 0;
    transition: var(--transition);
    max-width: 90%;
    text-align: center;
    font-weight: 500;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }
    
    .hydration-tracker {
        grid-template-columns: 1fr;
    }
    
    .glass-options {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .nav {
        gap: 5px;
    }
    
    .nav-btn {
        padding: 6px 8px;
    }
    
    .nav-text {
        font-size: 0.6rem;
    }
    
    .setting-buttons {
        flex-direction: column;
    }
    
    .btn-secondary,
    .btn-danger {
        width: 100%;
    }
}

@media (max-width: 480px) {
    .glass-options {
        grid-template-columns: 1fr;
    }
    
    .input-group {
        flex-direction: column;
    }
    
    .achievements-list {
        grid-template-columns: 1fr;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* High contrast mode */
@media (prefers-contrast: high) {
    :root {
        --primary: #5a4fcf;
        --text-dark: #000000;
        --text-light: #333333;
    }
}

/* Focus styles for accessibility */
button:focus,
input:focus,
select:focus {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Loading states */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid var(--primary);
    border-radius: 50%;
    border-top-color: transparent;
    animation: spin 1s linear infinite;
}

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