/* Design System */
:root {
    /* Colors - Soft gradients and pastels */
    --color-primary: #8B5CF6;
    --color-primary-light: #A78BFA;
    --color-primary-dark: #7C3AED;
    --color-secondary: #06B6D4;
    --color-secondary-light: #22D3EE;

    --color-bg: #FAFAFA;
    --color-bg-gradient: linear-gradient(135deg, #F3E8FF 0%, #E0E7FF 100%);
    --color-surface: #FFFFFF;
    --color-border: #E5E7EB;

    --color-text: #1F2937;
    --color-text-muted: #6B7280;
    --color-text-light: #9CA3AF;

    --color-success: #10B981;
    --color-error: #EF4444;

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;

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

    /* Border radius */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 12px 24px rgba(0, 0, 0, 0.1);
}

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

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

body {
    font-family: var(--font-family);
    color: var(--color-text);
    background: var(--color-bg-gradient);
    min-height: 100vh;
    line-height: 1.6;
}

/* Layout */
.view {
    display: none;
    min-height: 100vh;
    padding: var(--spacing-lg) var(--spacing-md);
    animation: fadeIn var(--transition-normal);
}

.view.active {
    display: flex;
}

.container {
    width: 100%;
    max-width: 600px;
    margin: 0 auto;
}

.timer-container {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
}

/* Typography */
h1, h2, h3 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--color-text);
}

h1 {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

h2 {
    font-size: 2rem;
    margin-bottom: var(--spacing-md);
}

h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.app-title {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    color: var(--color-text-muted);
    font-size: 1.125rem;
    margin-bottom: var(--spacing-xl);
}

.helper-text {
    font-size: 0.875rem;
    color: var(--color-text-light);
    margin-top: var(--spacing-xs);
}

/* Header */
header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

/* Buttons */
.btn {
    font-family: var(--font-family);
    font-size: 1rem;
    font-weight: 600;
    padding: 0.875rem 1.5rem;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-sm);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
}

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

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

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
}

.btn-secondary {
    background: var(--color-surface);
    color: var(--color-text);
    border: 2px solid var(--color-border);
}

.btn-secondary:hover:not(:disabled) {
    border-color: var(--color-primary-light);
    color: var(--color-primary);
}

.btn-large {
    font-size: 1.125rem;
    padding: 1.125rem 2rem;
    width: 100%;
    margin-top: var(--spacing-md);
}

.button-group {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-lg);
}

.button-group .btn {
    flex: 1;
}

/* Inputs */
input[type="number"],
input[type="text"],
textarea {
    font-family: var(--font-family);
    font-size: 1rem;
    padding: 0.875rem 1rem;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-sm);
    background: var(--color-surface);
    color: var(--color-text);
    transition: all var(--transition-fast);
    width: 100%;
}

input:focus,
textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(139, 92, 246, 0.1);
}

textarea {
    resize: vertical;
    line-height: 1.6;
}

/* Setup Sections */
.setup-section {
    margin-bottom: var(--spacing-xl);
}

.duration-inputs {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.input-group label {
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

.input-group input {
    width: 100%;
}

.input-group .unit {
    font-size: 0.875rem;
    color: var(--color-text-light);
    margin-top: calc(var(--spacing-xs) * -1);
    padding-left: var(--spacing-xs);
}

/* Participants */
.participants-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.participant-item {
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
}

.participant-item input {
    flex: 1;
}

.participant-item button {
    padding: 0.875rem 1rem;
    background: var(--color-surface);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    color: var(--color-text-muted);
    font-size: 1.25rem;
    line-height: 1;
    transition: all var(--transition-fast);
}

.participant-item button:hover {
    border-color: var(--color-error);
    color: var(--color-error);
}

.participant-item .github-indicator {
    font-size: 1.25rem;
    min-width: 1.5rem;
    text-align: center;
    transition: all var(--transition-fast);
}

/* Timer Display */
.current-time {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    font-size: 1rem;
    color: var(--color-text-light);
    font-weight: 500;
}

.timer-display {
    margin: var(--spacing-2xl) 0;
}

.timer-label {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-md);
}

.countdown {
    font-size: 8rem;
    font-weight: 700;
    line-height: 1;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-variant-numeric: tabular-nums;
}

.session-info {
    max-width: 500px;
}

.participants-display {
    font-size: 1.125rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-md);
}

.goal-display {
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--color-text);
    line-height: 1.6;
}

/* Session History */
.session-history {
    margin-top: var(--spacing-2xl);
}

.session-history h2 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
}

.empty-state {
    text-align: center;
    padding: var(--spacing-xl);
    color: var(--color-text-muted);
    font-size: 1rem;
}

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

.history-card {
    background: var(--color-surface);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
}

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

.history-date {
    font-size: 0.875rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-xs);
}

.history-participants {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-xs);
}

.history-participants a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.history-participants a:hover {
    color: var(--color-primary-dark);
    text-decoration: underline;
}

.history-goal {
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

.history-accomplishment {
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
    line-height: 1.6;
}

.history-footer {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: var(--spacing-xs);
}

.like-btn {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.25rem;
    padding: var(--spacing-xs);
    color: var(--color-text-light);
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.like-btn:hover {
    color: var(--color-error);
    transform: scale(1.1);
}

.like-btn.liked {
    color: var(--color-error);
}

.like-count {
    font-size: 0.875rem;
    font-weight: 600;
}

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

/* Responsive Design */
@media (max-width: 768px) {
    h1 {
        font-size: 2.5rem;
    }

    h2 {
        font-size: 1.75rem;
    }

    .countdown {
        font-size: 6rem;
    }

    .duration-inputs {
        grid-template-columns: 1fr;
    }
}

@media (min-width: 769px) {
    .view {
        padding: var(--spacing-2xl) var(--spacing-lg);
    }

    .button-group .btn-large {
        width: auto;
        min-width: 200px;
    }
}

/* Loading State */
.loading {
    display: inline-block;
    width: 1.5rem;
    height: 1.5rem;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
    vertical-align: middle;
}

.empty-state .loading {
    width: 2rem;
    height: 2rem;
    border-color: rgba(139, 92, 246, 0.3);
    border-top-color: var(--color-primary);
}

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

/* New Goal Section in Continue View */
#new-goal-section {
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 2px solid var(--color-border);
}