:root {
    --primary: #FF9A44;
    --secondary: #FC6076;
    --text-main: #ffffff;
    --text-muted: rgba(255, 255, 255, 0.7);
}

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

body {
    font-family: 'Inter', sans-serif;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: var(--text-main);
    height: 100vh;
    height: 100dvh; /* accounts for mobile browser UI */
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.app-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    padding: 2.5rem 1.5rem;
    max-width: 500px;
    margin: 0 auto;
    width: 100%;
}

header {
    text-align: center;
    margin-bottom: 2rem;
    animation: fadeIn 1s ease-out;
}

.logo {
    font-size: 2.2rem;
    font-weight: 600;
    letter-spacing: -0.5px;
    text-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.tagline {
    font-size: 1.1rem;
    font-weight: 300;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

.player-section {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2.5rem;
}

.session-selector {
    display: flex;
    gap: 0.5rem;
    background: rgba(255, 255, 255, 0.15);
    padding: 0.25rem;
    border-radius: 2rem;
    margin-bottom: -1rem;
    animation: fadeIn 1.2s ease-out;
}

.session-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 0.5rem 1rem;
    border-radius: 1.5rem;
    font-size: 0.9rem;
    font-family: inherit;
    cursor: pointer;
    transition: all 0.2s;
}

.session-btn.active {
    background: rgba(255, 255, 255, 0.25);
    color: white;
    font-weight: 600;
}

.session-info {
    text-align: center;
    animation: fadeIn 1.2s ease-out;
}

.session-info h2 {
    font-size: 1.8rem;
    font-weight: 400;
    margin-bottom: 0.5rem;
    letter-spacing: 0.5px;
}

.session-info .duration {
    font-size: 1.2rem;
    color: var(--text-muted);
    font-weight: 300;
    font-variant-numeric: tabular-nums; /* prevents jitter during countdown */
}

.player-controls {
    position: relative;
    width: 220px;
    height: 220px;
    display: flex;
    align-items: center;
    justify-content: center;
    animation: scaleIn 0.8s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.progress-ring {
    position: absolute;
    top: 0;
    left: 0;
    transform: rotate(-90deg);
}

.progress-ring__circle {
    stroke-dasharray: 628.32; /* 2 * pi * r (100) */
    stroke-dashoffset: 628.32;
    transition: stroke-dashoffset 0.1s linear;
}

.play-btn {
    width: 130px;
    height: 130px;
    border-radius: 50%;
    border: none;
    background: rgba(255, 255, 255, 0.15);
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1), inset 0 0 0 1px rgba(255, 255, 255, 0.2);
    transition: transform 0.2s, background 0.2s;
    z-index: 10;
}

.play-btn:active {
    transform: scale(0.92);
    background: rgba(255, 255, 255, 0.25);
}

.play-btn svg {
    margin-left: 6px; /* Offset to center the triangle visually */
    transition: all 0.3s;
}

.play-btn.playing svg {
    margin-left: 0;
}

.status-text {
    font-weight: 300;
    font-size: 1.1rem;
    color: var(--text-muted);
    min-height: 1.5em;
    transition: opacity 0.3s;
    animation: fadeIn 1.5s ease-out;
}

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

@keyframes scaleIn {
    from { opacity: 0; transform: scale(0.8); }
    to { opacity: 1; transform: scale(1); }
}